DEPARTMENT OF HEALTH AND HUMAN SERVICES 

CENTERS FOR DISEASE CONTROL AND PREVENTION

Advisory Committee on 

Immunization Practices (ACIP)

Summary Report

April 14, 2021

Atlanta, Georgia 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Table of Contents Page

Agenda 3

Acronyms 4-6

Welcome and Introductions 7

Coronavirus Disease 2019 (COVID-19) Vaccines

⬧ Introduction

⬧ Overview of Safety with Janssen's COVID-19 Vaccine (Ad26.COV2.S)

⬧ Update on Thromboembolic Events, COVID-19 Vaccines Safety Surveillance

⬧ VaST Assessment

⬧ Work Group Interpretation

⬧ Public Comments

⬧ Vote: Janssen COVID-19 Vaccine: Updated Recommendations for Use

8-44

Certification 45

Membership Roster 46-54
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Acronyms

AAFP American Academy of Family Physicians 

AAP American Academy of Pediatrics

ACHA American College Health Association 

ACIP Advisory Committee on Immunization Practices

ACOG American College of Obstetricians and Gynecologists

ACP American College of Physicians 

Ad.26 Adenovirus 26 

AE Adverse Event

AECI Adverse Events of Clinical Interest 

AESI Adverse Events of Special Interest 

AGS American Geriatric Society 

AHIP America’s Health Insurance Plans

AIM Association of Immunization Managers 

AMA American Medical Association

AOA American Osteopathic Association 

APhA American Pharmacists Association 

APTR Association for Prevention Teaching and Research

ASTHO Association of State and Territorial Health Officers 

AZ AstraZeneca

BSH British Society for Haematology 

CCDS Company Core Data Sheet 

CDC Centers for Disease Control and Prevention

CIOMS Council for International Organizations of Medical Sciences 

CISA Clinical Immunization Safety Assessment 

CMS Center for Medicare and Medicaid Services

COD Cause of Death

COI Conflict of Interest 

COVID-19 Coronavirus Disease 2019 

CSTE Council of State and Territorial Epidemiologists 

CT Computed Tomography 

CVA Cerebrovascular Accident 

CVST Cerebral Venous Sinus Thrombosis 

DoD Department of Defense

DSMB Data Safety Monitoring Board 

DVA Department of Veterans Affairs

DVT Deep Vein Thrombosis 

ED Emergency Department 

EHP Expert Haematology Panel 

EHR Electronic Health Record 

ELISA Enzyme-Linked Immunosorbent 

EMA European Medicines Agency 

EUA Emergency Use Authorization 

FDA Food and Drug Administration

FOIA Freedom of Information Act 

HAN Health Alert Network 

HCP Health Care Personnel / Provider / Professional 

HCW Health Care Workers 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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HHS (Department of) Health and Human Services

HIPAA Health Insurance Portability and Accountability Act 

HIT Heparin-Induced Thrombocytopenia 

HRSA Health Resources and Services Administration 

ICU Intensive Care Unit 

IDSA Infectious Disease Society of America 

IHS Indian Health Service 

IM Intramuscular

ISO Immunization Safety Office

ISTM International Society for Travel Medicine 

ITP Immune Thrombocytopenia 

ITT Immune Thrombotic Thrombocytopenia 

IVC Inferior Vena Cava 

IVIG Intravenous Immune Globulin 

IV-TPA Intravenous TPA 

J&J Johnson & Johnson 

MedDRA Medical Dictionary for Regulatory Activities 

MMWR Morbidity and Mortality Weekly Report

MRI Magnetic Resonance Imaging 

mRNA Messenger Ribonucleic Acid 

NAAT Nucleic Acid Amplification Test 

NACCHO National Association of County and City Health Officials 

NACI National Advisory Committee on Immunization Canada

NAPNAP National Association of Pediatric Nurse Practitioners 

NCEZID National Center for Emerging and Zoonotic Infectious Diseases 

NCHHSTP National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention 

NCIRD National Center for Immunization and Respiratory Diseases 

NEJM New England Journal of Medicine 

NFID National Foundation for Infectious Diseases 

NIH National Institutes of Health

NMA National Medical Association 

NSAID Nonsteroidal Anti-Inflammatory Agent 

OCP Oral Contraceptive Pills 

PE Pulmonary Embolism 

PF4 Platelet Factor 4 

PHAC Public Health Agency Canada 

PhRMA® Pharmaceutical Research and Manufacturers of America®

PI Principal Investigator

PIDS Pediatric Infectious Disease Society 

PRAC Pharmacovigilance Risk Assessment Committee 

PVT Portal Vein Thrombosis 

RCT Randomized Controlled Trial

RR Relative Risk

RSV Respiratory Syncytial Virus 

RT-PCR Reverse Transcriptase Polymerase Chain Reaction

SAE Serious Adverse Event 

SAHM Society for Adolescent Health and Medicine 

SARS Severe Acute Respiratory Syndrome 

SARS-CoV-2 Severe Acute Respiratory Syndrome Coronavirus-2 
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SHEA Society for Healthcare Epidemiology of America 

SLUSOM Saint Louis University School of Medicine 

SMEs Subject Matter Experts

SVT Splanchnic Vein Thrombosis 

tPA Tissue-Type Plasminogen Activator 

TTP Thrombotic Thrombocytopenic Purpura 

UK United Kingdom

US United States

UTI Upper Respiratory Tract Infection 

VA (US Department of) Veteran’s Affairs 

VAERS Vaccine Adverse Event Reporting System

VaST ACIP COVID-19 Vaccine Safety Technical Subgroup 

VITT Vaccine-Induced Immune Thrombotic Thrombocytopenia 

VSD Vaccine Safety Datalink

VSS Venous Sinus Stenosis 

WG Work Group

WHO World Health Organization
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José Romero, MD, FAAP

ACIP Chair

Amanda Cohn, MD

Executive Secretary, ACIP / CDC

Dr. Romero called to order the April 14, 2021 emergency meeting of the Advisory Committee on 

Immunization Practices (ACIP), the purpose of which was to discuss the pause of the Janssen 

Coronavirus Disease 2019 (COVID)-19 vaccine. He welcomed everyone and conducted a roll 

call, which established quorum. ACIP member, Dr. Sharon Frey, reported that she is a Principal 

Investigator (PI) for Saint Louis University School of Medicine (SLUSOM) on the Moderna and 

Janssen COVID-19 vaccine trials. No other no conflicts of interest (COIs) were declared for this 

meeting. A list of Members, Ex Officio Members, and Liaison Representatives is included in the 

appendixes at the end of the full minutes for the April 14, 2021 ACIP meeting.

Dr. Cohn welcomed everyone and explained that this meeting was arranged within the last 48 

hours to ascertain whether ACIP has enough information to make interim age or risk factorbased recommendations for the use of the Janssen vaccine, and what recommendation ACIP 

feels would be appropriate at this time give currently available information for the use of the 

Janssen vaccine given the safety signal identified. She acknowledged that while there likely 

would be numerous important scientific questions, comments and questions from ACIP 

members, Ex Officio members, and Liaison representatives should focus on the question and 

discussion at hand. She assured everyone that a lot of work is occurring in this space and what 

is known to date would be presented during this meeting, the goal of which was to determine 

whether ACIP has enough information to come to a recommendation and vote or if additional 

information is needed.

A Federal Register Docket was opened for oral and written public comments that would remain 

open through Friday, April 16, 2021. Individuals from the public were randomly selected to 

present their comments orally during this meeting. Those who were not selected and any other 

individuals wishing to make written public comments may submit them through 

https://www.regulations.gov using Docket Number CDC-2021-0042. Further information on the 

written public comment process can be found on the ACIP website.

ACIP members agree to forgo participation in certain activities related to vaccines during their 

tenure on the committee. For certain other interests that potentially enhance a member’s 

expertise, CDC has issued limited COI waivers. Members who conduct COVID-19 vaccine 

clinical trials or serve on data safety monitoring boards (DSMBs) may present to the committee 

on matters related to those vaccines and participate in discussion, but have been asked to 

withhold participation in discussion after the policy question has been deliberated and to abstain 

from any committee votes related to COVID-19 vaccine.

Opening Session: April 14, 2021 
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Introduction

Beth Bell, MD, MPH 

ACIP, COVID-19 Vaccine WG Chair

Clinical Professor, Department of Global Health

School of Public Health, University of Washington 

Dr. Bell introduced the session, indicating that there were some contextual issues the COVID-19 

Vaccine Work Group (WG) thought were important for ACIP to be aware of in order to 

assimilate the information to be presented. She then briefly reviewed adenovirus vector COVID19 vaccines, described rare clotting events seen after adenoviral vector vaccines following 

receipt of AstraZeneca (AZ) vaccine in Europe and Janssen vaccine in the US, and ACIP’s 

response.

There are 2 adenovirus vector vaccines, the Janssen/J&J vaccine and the AZ vaccine. The 

Janssen vaccine is a single-dose vaccine that uses human adenovirus 26 (Ad26) as its vector. 

An Emergency Use Authorization (EUA) was issued in the United States (US) in February 2021 

for the Janssen vaccine and the ACIP subsequently made recommendations. The European 

Medicines Agency (EMA) has authorized the Janssen vaccine for Europe, but no doses have 

been delivered to or administered in Europe. The AZ product is a 2-dose vaccine. The vector is 

a chimp adenovirus. It is awaiting EUA application in the US and is approved in the United 

Kingdome (UK) and Europe and has been in wide use in those areas and other parts of the 

world.

Concerns were raised for rare clotting events seen after COVID-19 adenovirus vector vaccines. 

The clinical syndromes after both vaccines appear similar. However, the extent to which the 

cases seen after each of these adenovirus vector vaccines represent exactly the same 

syndrome is not entirely clear at this time. The EMA’s safety committee, the Pharmacovigilance 

Risk Assessment Committee (PRAC), released a report on April 9, 2021 that concluded that 

there is a strong association and probable causal link between the AZ vaccine and rare clotting 

events.

There were press releases from the EU1 and the UK2. From the EU, there have been 62 cases 

of cerebral venous sinus thrombosis (CVST) and 24 cases of splanchnic vein thrombosis (SVT) 

with thrombocytopenia. Of these, 18 were fatal. Most occurred in females less than 60 years of 

age within 2 weeks of AZ vaccine receipt. Due to the different ways the vaccine is used in each 

country, the EU was not able to exclude age and gender as risk factors. From the UK, 79 cases 

of thrombosis and thrombocytopenia were reported. Among these, 19 were fatal. There were 44 

cases of CVST with 14 fatalities and 35 cases of other clots with 5 fatalities. Of the cases, 51 

were female and 28 were male. This is in the context of a denominator of 20.2 million doses of 

vaccine given in the UK. The press release estimated a risk of approximately 4 per million 

population, with a comment that there was a “slightly higher incidence” in younger age groups.

1 https://www.ema.europa.eu/en/news/astrazenecas-covid-19-vaccine-ema-finds-possible-link-very-rare-cases-unusual-blood-clotslow-blood

2 https://www.gov.uk/government/publications/use-of-the-astrazeneca-covid-19-vaccine-jcvi-statement/jcvi-statement-on-use-of-theastrazeneca-covid-19-vaccine-7-april-2021

Coronavirus Disease 2019 (COVID-19) Vaccines: April 14, 2021 
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Recently, there were reports3,4in the New England Journal of Medicine (NEJM) of low platelets 

(thrombocytopenia) and blood clots (thrombosis) after AZ vaccine in Europe. These cases came 

from Germany, Austria, and Norway. Many of these cases had platelet activating antibodies 

directed against platelet factor 4 (PF4), which is a clue to the possible mechanisms. The authors 

proposed a syndrome entitled “vaccine-induced immune thrombotic thrombocytopenia” (VITT).

Dr. Bell briefly reviewed CVST, given that this is one of the more predominant syndromes or 

conditions that has been identified. This involves thrombosis within large vessels that are 

draining blood from the brain as depicted in this figure5:

Silvis SM et al, Nature Reviews Neurology 13, 555-565(2017)

CVST occurs primary among people 20 to 50 years of age and mostly among females. Risks 

include pregnancy and other identified risks for coagulation such as oral contraceptives. 

Symptoms typically include headache, nausea, vomiting, other neurologic symptoms. The 

presentation can be acute or more chronic. This is an overall description of CVST and not 

specific to CVST with thrombocytopenia, which has been seen in the current situation.

The EMA’s PRAC does not make vaccine policy for the EU. Instead, each country weighs the 

risks and benefits of AZ vaccine individually. In terms of these findings in Europe, many 

countries have made new policy and have adopted age-based recommendations. On April 7, 

2021 in the UK, a recommendation was made to use the AZ vaccine in adults ≥30 years of age 

On April 8, 2021 in Australia a recommendation was made to use AZ vaccine in adults ≥50 

years of age. Other European countries have recommended use of the AZ vaccine in adults ≥55 

to ≥70 years of age, depending upon the country.

3 https://www.nejm.org/doi/full/10.1056/NEJMoa2104882?query=featured_home

4 https://www.nejm.org/doi/full/10.1056/NEJMoa2104840?query=featured_home

5http://www.med.umich.edu%2F1libr%2FStroke%2FSinusVeinThrombosis.pdf&usg=AOvVaw3qjvm4UOF

cHN-eR4O3Kyf8
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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As mentioned earlier, the Janssen vaccine received an EUA from FDA in February 2021 and 

ACIP made recommendations thereafter. On April 13, 2021, CDC and FDA issues a joint 

statement on the Janssen COVID-19 vaccine and made several points. As of April 12, 2021, 

more than 6.8 million doses of the Janssen vaccine have been administered in the US. CDC 

and FDA are reviewing data involving 6 cases of CVST in combination with low platelets 

reported among recipients of the Janssen vaccine in the US. The statement said that, “CDC will 

convene a meeting of the Advisory Committee on Immunization Practices on Wednesday to 

further review these cases and assess their potential significance.” The statement also indicated 

that, “Until that process is complete, we are recommending a pause in the use of this vaccine 

out of an abundance of caution.”

Another important point that was made in the press release was that one of the important 

reasons for the pause was to allow time to provide information to clinicians and the public about 

specific and unique aspects of diagnosis, treatment, and clinical signs and symptoms to 

monitor. The first step in that process was the issuance of a Health Alert Network (HAN)6

release on April 13, 2021 that provided recommendations for clinicians on diagnosis and 

treatment, for public health in terms of case reporting through the Vaccine Adverse Event 

Reporting System (VAERS), and for the public on clinical signs and symptoms to monitor and 

when to seek medical attention. A few of the details in that report include the following:

❑ Recommendations for Clinicians: diagnosis and treatment

– Evaluate patients with a screening PF4 enzyme-linked immunosorbent (ELISA) 

assay as would be performed for autoimmune heparin-induced thrombocytopenia 

(HIT). Consultation with a hematologist is strongly recommended.

– Do not treat with heparin, unless HIT testing is negative.

❑ Recommendations for Public Health: case reporting through VAERS

– Encourage healthcare providers and the public to report all serious and lifethreatening adverse events and deaths following receipt of COVID-19 vaccines to 

VAERS.

❑ Recommendations for the Public: clinical signs and symptoms to monitor

– Contact healthcare provider, or seek medical care if you develop severe headache, 

abdominal pain, leg pain, or shortness of breath within three weeks after vaccination 

with the J&J COVID-19 vaccine.

The ACIP response thus far has included a meeting on April 12, 2021 of the Vaccine Safety 

Technical Group (VaST); an ACIP COVID-19 Vaccines WG meeting on April 13, 2021; and this 

emergency ACIP meeting on April 14, 2021 with the purpose of considering the implications of 

reported cases of thrombosis and thrombocytopenia after the Janssen/J&J vaccine on 

vaccination policy. Dr. Bell indicated that the day’s agenda would include presentations on the 

following topics, which would be followed by a public comment session:

❑ Overview of Safety with Janssen’s COVID-19 Vaccine, Ad26.COV2.S

❑ CVST with Thrombocytopenia after COVID-19 Vaccines from VAERS for the Period March 

2-April 12, 2021

❑ ACIP COVID-19 VaST Assessment

❑ COVID-19 Vaccine WG Interpretation

❑ Public Comment

❑ Potential Vote: Updated Interim Recommendations for use of Janssen COVID-19 Vaccine

6 HAN Archive - 00442 | Health Alert Network (HAN) (cdc.gov)
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Safety Overview of Janssen’s Ad26COV2.S COVID-19 Vaccine & Epidemiology Analysis

Aran Maree, MD

Chief Medical Officer, Pharmaceuticals

Head, Global Safety Organization

Janssen Pharmaceuticals Companies of Johnson & Johnson

Kourtney Davis, PhD, MSPH

Epidemiologist

Senior Director and Head, Therapy Area Matrix

Global Epidemiology at Janssen R&D, LLC

Dr. Maree shared relevant Janssen clinical and post-authorization data on the subject of 

thrombosis, particularly in terms of CVST with thrombocytopenia, and described the background 

epidemiological dataset in the context of Janssen’s overall evaluation. He emphasized that the 

safety and well-being of the people who use Janssen’s products is their number one priority. 

While causality has not been fully established between these very rare events and Janssen’s 

vaccine, they recognize that these events could represent an important potential risk with the 

Janssen vaccine. They are in the process of updating their Company Core Data Sheet (CCDS) 

and working with health authorities to update labeling appropriately. Johnson & Johnson (J&J) 

will continue to monitor this potential risk and is committed to efforts to ensure vaccinee and 

healthcare professional (HCP) awareness of the important signs and symptoms of this event, as 

well as appropriate diagnosis and management.

To review the vaccine data, Janssen has 2 Phase III pivotal clinical trials in its program. Study 

3001 is a 1-dose Phase III trial and Study 3009 is a 2-dose ongoing study that remains blinded. 

For Study 3001, 43,783 participants have been vaccinated. In the 28 days after vaccination, 

there have been 4 deep vein thromboses (DVTs) in the active arm and 2 cases in the placebo 

arm. There are 2 cases of pulmonary embolism (PE) in the active arm and 1 case in the placebo 

arm. There has been 1 CVST and 1 venous thrombosis of a limb in the active arm and none in 

the placebo arm. The total number of cases accrued are 11 DVTs in the active arm and 3 in the 

placebo arm, 9 PEs in the active arm and 4 in the placebo arm, 1 CVST in the active arm and 1 

in the placebo arm, 1 venous thrombosis in a limb in the active arm and none in the placebo 

arm, and 1 venous embolism in the active arm and none in the placebo arm. In Study 3009, the 

ongoing Phase III 2-dose trial, 28,277 participants have been vaccinated. This study remains 

blinded and the data are presented as blinded. In this study, there has been 1 PE event up to 28 

days after vaccination. There are now 2 DVTs at all time points and 4 PEs beyond 28 days.

There also is an ongoing large, open-label study in South African HCPs that has enrolled 

272,438 participants to date out of a total anticipated 500,000 participants. As of April 9, 2021, 

no CVST cases have been reported. There has been 1 case of PE, but there has been no 

information on platelet or COVID status with this case. There has been 1 cerebrovascular 

accident (CVA) in a 38-year-old female 8 days after vaccination. Additional information is being 

actively sought on this case through the Principal Investigator (PI). There has been 1 case of 

retinal vein thrombosis in a 68-year-old diabetic whose platelet count was reported as normal.

Dr. Maree reviewed all known cases of CVST and all known cases of thrombosis with 

thrombocytopenia with Janssen COVID-19 vaccine to date. Per the CDC, the number of 

vaccinations to date with the Janssen COVID-19 vaccine in the US is 7.2 million as of April 14, 

2021. Janssen is aware of 6 post-authorization cases of CVST, 4 of 6 with low platelets and 2 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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unknown, within these vaccinated individuals. The following table describes all known cases of 

thrombosis with thrombocytopenia with the Janssen COVID-19 vaccine:

The first 2 rows are the cases already described within the Phase III clinical trial program. The 

following rows are the post-authorization cases. In Study 3001 in the first row, the case was of a 

25-year-old male who received vaccine. The report was of a CVST with hemorrhage. It was 

noted that the subject had stenosis of his transverse sinus, a suspected upper respiratory tract 

infection (UTI), and a platelet count of 64,000. It has recently been retrospectively determined 

that his anti-PF4 antibodies were negative at baseline, but were positive at approximately Day 

28 post-vaccination. His COVID status was negative and time to onset was 8 days after 

vaccination. He was treated with heparin, tissue-type plasminogen activator (tPA), received 

platelets, had 2 balloon angioplasties and thrombectomies due to the discovery of a venous 

sinus stenosis (VSS). He has recovered and has been discharged from the hospital. The 

second participant from the placebo arm of Study 3001 is a 24-year-old female who has 

recovered from a CVST. She had a normal anti-PF4 antibody test post-vaccination and postincident. Her COVID status was negative. The time to onset was more than 50 days after 

vaccination.

Post-authorization phase come to Janssen primarily from 2 sources. The first 3 cases described 

and the final case came through VAERS, the joint CDC and FDA reporting system. Janssen 

gains access to these reports when they are refreshed every Friday, so there is a slight lag in 

reporting to Janssen. Understandably for privacy reasons, there is significant reduction of some 

of the data fields and it is not possible for Janssen to follow-up for further information or 

evaluation beyond what is presented to them in the preliminary report. They can attempt to do 

so through Freedom of Information Act (FOIA) applications, and FDA has been very supportive 

in helping Janssen to expedite these requests. The other cases come to Janssen directly 

through their call center, website, or via email. This allows Janssen to acquire further 

information and result in a richer dataset.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
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The first case that came through VAERS post-authorization was a 45-year-old female who 

presented with CVST with hemorrhage. No risk factors were described in the report, the report 

notes the term “thrombocytopenia,” COVID status was unknown, time to onset after vaccination 

was reported at 11 days, treatment was not described, and this patient died. The second case 

that came through VAERS was a 48-year-old female who presented with CVST, risk factors 

were unknown, platelet count was unknown, COVID status was not described, and time to onset 

was 10 to 14 days after vaccination. She was treated with heparin and at this time, she is 

described and reported as not recovered. The third case that came through VAERS was a 59-

year-old female who presented with extensive DVT on her left side, had known coronary artery 

disease, had a platelet count of 15,000, COVID status was unknown, and time to onset after 

vaccination was 7 days. A vena cava filter was inserted into her inferior vena cava (IVC) and 

she also underwent a thrombectomy. The day after the procedure to place the IVC, she was 

reported to have significant thromboses and DVTs on her right side, and it was questioned as to 

whether this was secondary to the intervention or partially facilitated by the intervention through 

her right side to place the IVC. She is reported as not recovered at this time.

The next case was reported as a Janssen serious adverse event (SAE) that came from Nevada. 

This is an 18-year-old female who presented with CVST with hemorrhage, risk factors are 

unknown, platelet count was 16,000, COVID status was unknown, and time to onset after 

vaccination was 14 days. She initially was treated with heparin and then switched to what was 

reported at “treatment according to the British Guidelines,” which Dr. Maree said he took to refer 

to the Guidance produced by the Expert Haematology Panel (EHP) from the British Society for 

Haematology (BSH). She underwent a thrombectomy and her status is listed as not recovered 

at this time.

The next case was reported directly to Janssen through pre-publication by the New England 

Journal of Medicine (NEJM) by an Editor Notification. This case from Nebraska is a 48-year-old 

female who was reported as presenting with thrombotic thrombocytopenic purpura (TTP), SVT, 

and CVST. She initially was given heparin and then additional hepatic and SVT was reported. 

Her risk factors were unknown, her platelet count was 13,000, she was reported to have a high 

D-Dimer and a positive anit-PF4 antibody test, her COVID status was reported as negative, and 

time to onset was 14 days after vaccination. She first was treated with heparin but was switched 

to argatroban after the anit-PF4 antibody test and also was given intravenous immune globulin 

(IVIG). At this time, her status is reported as not recovered.

The next case is from New Jersey/Pennsylvania and also was reported directly to Janssen. This 

case is a 26-year-old female who presented with CVST, PE, and portal vein thrombosis (PVT). 

Risk factors described include obesity, platelet count was 120,000, she had a high D-Dimer, she 

had a positive anti-PF4 assay, her COVID status was negative, and time to onset after 

vaccination was 7 days. She was treated with heparin and then with IVIG and has been 

discharged from the hospital.

The final case was notified to Janssen through VAERS and has very limited details on the 

company side. This case is of a 28-year-old female and details are pending under an FOIA 

application via FDA to CDC. 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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To go into more detail on 3 of the cases, the NEJM pre-publication case from the University of 

Nebraska was reported to Janssen on April 8, 2021. This 48-year-old woman was described as 

having an unremarkable past medical history who presented to the emergency department (ED) 

after 3 days of malaise and abdominal pain. The initial evaluation describes mild anemia and 

severe thrombocytopenia with a platelet count of 13,000. A blood smear confirmed marked 

reduction in platelet count with occasional schistocytes. She had hypofibrinogenemia, a 

prolonged aPTT, markedly elevated D-Dimer, and was noted to have extensive SVT on 

computed tomography (CT). She was transferred to the reporting institution, with further 

evaluation and progression noted of the thrombosis on heparin. She had a negative 

reverse transcriptase polymerase chain reaction (RT-PCR) test for SARS-CoV2 RNA. A head 

CT for new-onset headaches reported in her secondary hospital showed CVST. 

Thrombosis progressed with hemorrhagic stroke despite treatment with heparin. She underwent 

repeat CT angiography, which showed new thrombus involving right hepatic and splenic veins. 

Further inquiry revealed that the patient received the Ad26.COV2.S vaccine 14 days before 

symptom onset. The report describes evidence and management of a possible immune 

thrombotic thrombocytopenia (ITT). She had positive anti-PF4/heparin antibodies by ELISA. Her 

latex-enhanced immunoassay was negative. Her heparin was switched in the second hospital to 

argatroban and she was given IVIG 1 gm/kg of body weight for 2 days. Her platelet count was 

reported to have increased from 30,000 to 145,000 over 5 days. She remains critically ill as of 

the last report.

Further details were received on the next case reported directly to Janssen on a follow-up 

phone call with the physician on April 12, 2021. This is a 26-year-old woman who is described 

as an overweight but active gym instructor who has no history of clotting disorder and is on no 

medication. She initially presented to the ED with a severe headache approximately 1 week 

following vaccination. She was discharged home from ED with paracetamol and Benadryl®. 

However, her headache persisted and she was subsequently admitted to the hospital another 

week later with abdominal pain and rapid heart rate. COVID-19 infection ruled out, although the 

exact test is unknown. A laboratory evaluation revealed thrombocytopenia with a platelet count 

of 120,000, elevated D-Dimer, and normal fibrinogen. The diagnostic scan showed CVST, PVT, 

and PE. She initially was treated with heparin and is described as having been switched to IVIG 

after the clinical team became aware of a positive anti-PF4 antibody test result. Her platelet 

count reportedly started to increase before the IVIG was commenced. This patient has been 

discharged home on oral anticoagulant after a period of 1 to 1.5 weeks in the hospital.

The case from Study 3001 in the clinical trial program is of a 25-year-old healthy, active male 

who was vaccinated on September 21, 2020. He began feeling progressively unwell 8 days 

post-vaccination described as fatigue, faintness, nausea, and a headache for which he took 

nonsteroidal anti-inflammatory agents (NSAIDs). At 11 days post-vaccination, he had continued 

fatigue, weakness, and nausea and developed abdominal pain and a headache. A COVID-19 

swab taken by the PI on that date was negative. He was then hospitalized 19 days postvaccination on October 9. 2020 after visual disturbance and collapsing. The laboratory 

evaluation reported a platelet count of 64,000; PT of 17.7, INR of 1.46; fibrinogen 154, white 

blood count of 12.4; hemoglobin of 12.7, and hematocrit of 36.1. He underwent CT, magnetic 

resonance imaging (MRI), and venogram and his diagnosis was CVST and secondary cerebral 

haemorrhage. He underwent repeated cerebral vascular sinus thrombectomy and balloon 

venoplasty due to re-occlusion and treatment for stenosed cerebral sinus. He also was treated 

with low-molecular weight heparin and intravenous TPA (IV-TPA). Extensive haematology and 

infectious disease laboratory evaluations showed inconclusive results. The patient was 

discharged on treatment with apixaban. Last week, stored serum tested positive for anti-PF4 

antibodies for the post-vaccination phase and a negative baseline laboratory anti-PF4 test. This 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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gentleman recovered after repeat thrombectomy and balloon angioplasty procedures. He was 

described as having severe epiglottitis while in the hospital and his discharge medications 

include apixaban.

Dr. Davis described the epidemiological analysis that Janssen has conducted to assist in this 

investigation. Janssen conducted a published literature search that resulted in retrieval of 

articles from the US, EU, Middle East, Asia Pacific. An interim meta-analysis analysis also was 

conducted across 4 large US healthcare claims databases and 1 US electronic health record 

(EHR) database. That study design was intended to generate background incidence rates of 

CVST. The study period 2017 to 2019 was used to generate the incidence of the outcome 

“cranial venous sinus thrombosis.” The methods used for that analysis are similar to those used 

in a multi-national network cohort study of 15 adverse events of special interest (AESI). The 

results of that large network study have been shared with FDA and EMA and are published on a 

pre-print server. A manuscript of those AESI background is also under review7. This table shows 

CVST background incidence rates from the published literature in the bottom rows along with 

those from the database analyses conducted by Janssen and by the ACCESS group in Europe:

7 Xintong et al., Characterizing the incidence of adverse events of special interest for COVID-19 vaccines 

across 8 countries: a multinational network cohort study. Manuscript under review: 

https://www.medrxiv.org/content/10.1101/2021.03.25.21254315v1

 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Beginning with the published literature, the overall adult background incidence rates are shown 

per 100,000 person years. Those range from 0.2 to 0.5 per or 2 to 5 per million. In the older 

studies, rates are higher at upwards of about 15 per million in the most recent studies that come 

from the bottom 2 references on the table. The results of Janssen’s claims database are shown 

in the first row, but are not yet published as they were just generated. Those are displayed by 

age and sex, which Janssen thought was important as there potentially is a higher risk among 

younger women. The highest rates are observed in women 18 to 34 years of age at 2.6 per 

100,000 or 26 per million, with an overall rate among women 18 to 85 years of age of 17 per 

million or in men of 12 per million. This provides an understanding of the range of the estimates 

from more contemporary claims databases. Limitations of the claims databases are that there is 

no validation of the outcome of CVST, and Janssen did the best they could with the diagnoses 

that come from hospitalized events. A stratified analyses is underway of CVST incidence by 

thrombocytopenia.

Dr. Maree pointed out that while ethnicity is not reported in all of the post-authorization reports, 

it is known that the single case of CVST in the active arm in Study 3001 was in a 25-year-old 

white male. They also have meta-data on two of the post-market reports indicating that they 

were 2 white females. However, ethnicity is not described in most case reports. Janssen is 

conducting an intensive ongoing review of internal and publicly available data including, but not 

limited to, the following:

❑ Evolving literature on the relationship between COVID and thrombocytopenic and 

thrombotic events

❑ Case reports of association between thromboembolic events, including CVST with ITP and 

TTP

❑ US VAERS data on thrombocytopenic and thrombotic events and other AESIs for all 

available vaccines

❑ European EUDRAVIGILANCE AE dataset

In conclusion, Dr. Maree reiterated that based on the current data, Janssen believes the overall 

benefit-risk profile for its COVID-19 vaccine is positive across the population for which it is 

authorized and strongly supports awareness of the signs and symptoms of this very rare event 

and the recommendations to ensure the correct diagnosis, treatment, and reporting by HCPs.

Discussion Points

Dr. Romero asked what the significance is of the latex-enhanced negative assay on the first 

case presented for anti-PF4 antibodies.

Dr. Maree said that it has been represented to him that for the PF4, it is important to use the 

ELISA test as some of the other assays may not be as sensitive. In the case where both were 

reported to them, they represented both.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Dr. Bernstein observed that a number of the patients were described as having recovered. He 

wondered whether the patient who was described as discharged from the hospital was 

considered recovered, how recovered is defined in terms of whether it means patients are back 

to normal or are still be treated, and if patients who are considered to be recovered continue to 

be monitored.

Dr. Maree indicated that the reports to VAERS, which are known as Council for International 

Organizations of Medical Sciences (CIOMS) reports, have a number of fields. This includes a 

field for status, with a limited number of options available, so some of what is represented is 

somewhat clunky form terminology due to the limited options available.

Referring to Slide 15 with the background rates, Dr. Bernstein asked whether these are the 

cases without thrombocytopenia.

Dr. Davis clarified that this is any CVST and that it is not stratified in this analysis by 

thrombocytopenia status.

Dr. Sanchez asked whether any of the women had a recent pregnancy, were postpartum, had a 

history of preeclampsia, and/or had medication listed such as oral contraception.

Dr. Maree said that they did scan all reports and sent questions back to those for whom they 

had identifiable reporters. They do not have reports of recent pregnancy, being postpartum, or 

having suffered preeclampsia. He did not believe that any of the participants other than the 24-

year-old woman in the placebo on who had a CVST at beyond 50 days was on oral 

contraceptive pills (OCP), but to the best of his recollection this was not described for any of the 

cases post-vaccination.

Dr. Cohn indicated that the next presentation by Dr. Shimabukuro would go through the VAERS 

reports with some specificity and will share any additional information they have about those 

cases.

Dr. Poehling recalled that the one case from New Jersey/Pennsylvania that was reported 

directly to Janssen had CVST with PE, and she wondered whether Janssen is aware of any 

cases of PE without CVST and if they are looking for these, how many cases have been 

reported, and the timeframe.

Dr. Maree said that while they have had cases of PE, none were reported in the context beyond 

what has been described with concomitant thrombocytopenia. Referring to Table 18, Dr. Maree 

indicated that they have interrogated the VAERS database looking for thrombocytopenic, 

thromboembolic, and hemorrhagic events that have been observed after vaccination. As of April 

9, 2021, there have been 55 reports of thromboembolism, 4 reports of thromboembolism with 

thrombocytopenia, 2 cases of CVST, and other AEs with an exposure of 4.9 million doses 

administered. In the Phase III program shown on Slide 19, in the summary of total venous 

thrombosis events up to 28 days, there are 2 PEs in the active arm and 2 in the placebo arm. 

This again reiterates in a more comprehensive slide venous thrombosis events from the 43,000-

person study.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Dr. Ault recalled mention of the Ebola and respiratory syncytial virus (RSV) vaccines that used 

the same vector and for which there were no cases in those trials. He asked whether there were 

any thrombotic events of thrombocytopenia events, especially an imbalance in the Ebola trial 

that included a fair number of pregnant and postpartum women.

Dr. Marnee confirmed that there were not CVST events and called upon Dr. Douoguih from 

Janssen’s Clinical Team to respond as well.

Dr. Douoguih emphasized that they have not seen any CVST events in any of their programs, 

with the Ebola and RSV programs being the biggest ones. There have been some cases of DVT 

and PE, but none to their knowledge are associated with thrombocytopenia and there were 

clear risk factors. There was 1 case of immune thrombocytopenia (ITP) in the RSV program, so 

they will determine whether there are any stored samples that can be tested. The denominator 

for this case about 200,000 people or more who received at least 1 dose.

Dr. Long requested that Dr. Davis provide additional information about how the epidemiologic 

studies were done related to the HCPs under surveillance. She understood that they had to be 

in the system for a year but was not clear whether they were followed for a year and if these are 

basically numbers of cases expected in 100,000 people over 1 year. The clustering of these 

cases around the vaccine is very provocative and compelling, so she also wondered whether 

any additional analyses were done to estimate the number. If they used some random event 

such as the anniversary of the person’s birthday and asked in 1 month after some random event 

what then would be the number of cases per 100,000 people in 1 month’s time. She is tempted 

to want to divide by 12 for the background incidence in a month’s time unless there is some 

other reason for these other sporadic cases to be clustered, which would change very much 

what the dynamic was within the expected range if they occurred within 1 month or even 2 

months of vaccination.

Dr. Davis indicated that this is a classic incidence cohort design in which the person had to be 

observed in the database for a year prior to prove that they did not have a CVST in their history. 

It is looking for new diagnoses of CVST in a 1-year follow-up period. Regarding picking a 

random date and looking out 1 month, they did look up to a year. She said she did not have a 

specific way to answer the question about generating a person month estimate. When they 

convert this to an expected number when the formal observed to expected analysis is done, 

they generate it for a 28-day risk period and then divide by 12 in order to create the expected 

number. That also would be using the age- and sex-specific rates. They apply it to the actual 

exposure distribution for the vaccinated individuals when they go through this exercise. 

Simplistically speaking, they want to use these rates to convert them to an expected 28-day 

observed and divide by 12.

Dr. Cohn emphasized that some of this would be further addressed in Dr. Shimabukuro’s 

upcoming presentation.

Ms. McNally said that as the consumer representative she was trying to understand the 

reporting process on safety events. She requested that Dr. Maree explain how Janssen makes 

FDA and CDA aware of reports directly to Janssen and the extent to which Janssen shares the 

details of those cases with FDA and CDC.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Dr. Maree replied that when subjects are vaccinated in a Janssen clinical trial, there is an 

expedited SAE reporting via the clinical trial process to the health authorities. In the postauthorization phase when the vaccine is being given to the public, there are a number of ways 

in which patients experiences or AEs can be reported. When patients receive a vaccine, they 

are given a factsheet and information is presented to them on reporting to the FDA and CDC via 

VAERS. There is the v-safeSM program that sends regular text messages to vaccine recipients 

who sign up for their experience in the post-authorization first few weeks, which then is sent to 

VAERS. If any reports of AEs come directly to Janssen, there is an expedited reporting process 

whereby Janssen processes those cases and sends them immediately to the FDA, EUA, and 

other global health authorities. There is a continuing, sustained, rapid reporting of events 

between the companies and the health authorities in the various jurisdictions.

Update on Thromboembolic Events After Janssen COVID-19 Vaccine

Tom Shimabukuro, MD, MPH, MBA

CDC COVID-19 Vaccine Task Force 

Vaccine Safety Team

National Center for Emerging and Zoonotic Infectious Diseases

Centers for Disease Control and Prevention

Dr. Shimabukuro provided a brief background and further detailed the reports of CVST with 

thrombocytopenia (low platelets) following Janssen COVID-19 vaccine. He explained that 

platelets, which also are called thrombocytes, are colorless blood cells that help blood clot. A 

normal platelet count is 150,000–450,000 per microliter. In the medical world that is usually 

short-handed to 150-450. Platelets are important in that they stop bleeding by clumping and 

forming plugs in blood vessel injuries. Thrombocytopenia is a condition in which one has a low 

blood platelet count of <150,000 per microliter of blood. Dangerous internal bleeding can occur 

when someone’s platelet count falls below 10,000 platelets per microliter. Though rare, severe 

thrombocytopenia can cause bleeding into the brain, which can be fatal8. This issue has been in 

the public view primarily because of the cases of rare and unusual blood clots with low platelets 

following the AZ COVID-19 vaccine. May of these were CVSTs9.

In terms of the Janssen COVID-19 vaccine timeline of key events, Janssen received its EUA on 

February 27, 2021. ACIP issued an interim recommendation on the following day and 

vaccination started on March 2, 2021. The first report of CVST with thrombocytopenia was 

received by VAERS on March 19, 2021. These are serious reports because individuals wind up 

in the hospital and meet the definition for SAE. That initiates record collection and investigation 

by CDC and FDA. These reports were received from the period March 19, 2021 through April 8, 

2021. An expedited records request was conducted. Physicians at FDA, CDC, and in the 

Clinical Immunization Safety Assessment (CISA) program conducted detailed reviews of these 

cases and their accompanying medical records. This investigation is still ongoing, but CDC and 

FDA recommended a pause in the Janssen vaccine on April 12, 2021. A HAN was issued on 

April 13, 2021 and the investigation continues. This is a screenshot of the CDC HAN. The 

second paragraph reflects some of the key points10:

8 https://www.mayoclinic.org/diseases-conditions/thrombocytopenia/symptoms-causes/syc-20378293

9 https://www.ema.europa.eu/en/news/astrazenecas-covid-19-vaccine-ema-finds-possible-link-very-rarecases-unusual-blood-clots-low-blood

10 https://emergency.cdc.gov/han/2021/han00442.asp
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Dr. Shimabukuro shared again the Silvis SM et al Figure 1 of the cerebral venous sinus 

anatomy that Dr. Bell showed in the introduction, emphasizing that the brain is one of the most 

vascular organs in the body. As such, it requires substantial venous drainage. Fairly large veins 

drain the blood from the brain. There is quite a lot of redundancy here, so if there is an issue in 

one area, other parts of the venous drainage can compensate. When these CVSTs become 

symptomatic, these are significant blood clots that are causing the problems.

The epidemiology and background rates for CVST11,12,13 in general are less well-understood 

because this is such a rare condition. CVST in general occurs at about 0.22–1.57 per 100,000 

in the population. It is implicated in about 0.5-1% of all strokes. It is primarily a disease of 

younger individuals, with a median age of 37 years. Only 8% of patients are >65 years of age. 

The Female to male ratio is 3:1. Risk factors14 include genetic or acquired prothrombotic 

condition, oral contraceptive use, pregnancy and the post-partum period, malignancy, infection, 

and mechanical precipitants such as lumbar puncture. The most common presentations include 

isolated intracranial hypertension syndrome (headache with or without vomiting, papilledema, 

and visual problems), focal syndrome (focal deficits, seizures, or both), and encephalopathy 

(multifocal signs, mental status changes, stupor, or coma). More rare presentations include 

cavernous sinus syndrome, subarachnoid hemorrhage, and cranial nerve palsies.

The data for the case reports on which Dr. Shimabukuro presented came from VAERS, which is 

the nation’s early warning system for vaccine safety. It is a spontaneous or passive reporting 

system. It depends upon astute HCP to recognize and report potential AEs promptly to VAERS. 

It is designed to detect rare and SAEs that might indicate a safety problem. It is subject to the 

limitations of passive surveillance in general, but it performed exactly as intended in this case. It 

has such a wide scope, pretty much anyone in the population who is eligible to receive a 

vaccine is a potential subject. VAERS is quite robust and rapidly detected these rare, unusual 

11 Cerebral vein and dural sinus thrombosis in Portugal: 1980-1998. Ferro JM, Correia M, Pontes C, Baptista MV, Pita F, Cerebral 

Venous Thrombosis Portuguese Collaborative Study Group (Venoport) Cerebrovasc Dis. 2001;11(3):177.

12 The incidence of cerebral venous thrombosis: a cross-sectional study. Coutinho JM, Zuurbier SM, Aramideh M, Stam J. Stroke. 

2012 Dec;43(12):3375-7.

13 The incidence of cerebral venous thrombosis: a cross-sectional study. Coutinho JM, Zuurbier SM, Aramideh M, Stam J. Stroke. 

2012 Dec;43(12):3375-7.. 

3 Cerebral Venous Sinus Thrombosis Incidence Is Higher Than Previously Thought: A Retrospective Population-Based Study. 

Devasagayam S, Wyatt B, Leyden J, Kleinig T. Stroke. 2016 Sep;47(9):2180-2.

14 Diagnosis and management of cerebral venous thrombosis: a statement for healthcare professionals from the American Heart 

Association/American Stroke Association. Saposnik G, et al. 2011;42(4):1158.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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thrombotic events in the presence of thrombocytopenia. This is a good example of how robust 

the US vaccine safety monitoring system is and how in this case, during a large-scale national 

mass vaccination program, the system worked and functioned exactly as planned. This is an 

example of a success story for vaccine safety.

To give a high-level overview of what is being seen for all COVID-19 vaccines, Dr. Shimabukuro 

shared reports of CVST to VAERS after COVID-19 vaccines as of April 12, 2021. For the 

Janssen COVID-19 vaccine, there are 6 reports of CVST with thrombocytopenia (platelet counts 

<150,000/mm3) following 6.86 million doses administered. That comes out to a reporting rate of 

0.87 cases per million doses administered, or just under 1 case per million doses administered. 

By contrast for the Pfizer-BioNTech COVID-19 vaccine, there have been 0 reports following 

97.9 million doses administered. For the Moderna COVID-19 vaccine, there are 3 reports 

following 84.7 million doses administered. All 3 of these reports had normal platelet counts and 

the onsets occurred at 2, 6, and 12 days after vaccination. For the purpose of this specific 

condition, these 3 reports are not considered to be cases because they had normal platelet 

counts. This is considered to be a reporting rate imbalance between the Janssen vaccine and 

the messenger ribonucleic acid (mRNA) vaccines.

While manufacturers are required to report to VAERS, anyone can report (e.g., HCP, parents, 

patients, caregivers, et cetera). If reports come in that are classified as “serious” according to 

the regulatory definition (e.g., death, hospitalization, permanent disability, life-threatening 

illness, prolongation of hospitalization, congenital anomaly or defect), that information is 

captured in the VAERS form. For the Janssen vaccines, folks at CDC and FDA are performing 

what is essentially a pre-screening of these serious reports by pulling them out to look at them 

before they go through the normal processing. When they began to recognize some of these 

unusual reports of CVST with thrombocytopenia, which they were looking for because of the 

information coming out of Europe, they were able to identify potential cases rapidly and conduct 

an expedited follow-up to obtain medical records and connect with the healthcare facilities. That 

often was done by people in the Immunization Safety Office (ISO) directly in reaching out to 

expedite collection of records. Through April 12, 2021, 6 cases have been identified. The 

median age is 33 years, with a range of 18 to 48 years of age. The median time to symptom 

onset is 8 days, with a range of 6 to 13 days. This median time to onset differs from what was in 

the HAN. The analyses are continually being refined as additional data are gathered. In the 

HAN it was 9 days, with a median range of 6 to 13. All cases occurred in white females, with 1 

having a potential risk factor of current estrogen/progesterone use. None of the women were 

pregnant or post-partum. Pre-existing conditions included Obesity (n=3), Hypothyroidism (n=1), 

Hypertension (n=1), and Asthma (n=1). There were no known coagulation disorders.

As noted earlier, thrombosis usually does not occur in the presence of low platelets. These case 

presentations are atypical. Platelets facilitate the clotting of blood. In these cases, clots are 

forming in large vessels in the presence of low platelets. This is a paradox as it usually does not 

happen. The Janssen case presentations are consistent with the case presentations observed 

after receipt of the AZ COVID-19 vaccine. This table lists the initial and late signs and symptoms 

among CVST patients who received Janssen vaccine, with the list in no particular order:
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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The important thing to note here is the initial features are largely non-specific symptoms, which 

may seem mild and not that clinically significant when a patient starts to become symptomatic.

In 5 of these 6 cases, headache is the initial presenting feature. Therefore, it is important in the 

current setting that HCP maintain a high index of suspicion for possible CVST and confirm 

vaccination history among other things.

This table provides the locations of CVST, intracerebral hemorrhage, and other thromboses in 

the 6 cases:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

23

The important thing to point out is that while these were all 6 cases of CVST, the thromboses 

were not limited to the cerebral venous drainage system. In 3 of these cases, there were 

substantial clots in other large vessels in other parts of the body, such as portal vein and right 

pulmonary artery. Another individual had bilateral lower extremity VTE and right internal jugular 

vein, while another had portal vein. This is consistent with what was observed in the cases that 

occurred after the AZ COVID-19 vaccine in Europe. It also has caused CDC to cast a wider net 

in the future to look for thromboses in the presence of thrombocytopenia. Certainly, most of the 

cases so far have been CVST. That does not mean that CVST is the only thing to look for. It is 

important to look for substantial blood clots in individuals with thrombocytopenia regardless of 

whether they are in the central nervous system (CNS).

While there is some evidence that having COVID-19 may place one at risk for thrombotic 

events, there is nothing remarkable in the SARS-CoV-2 tests for the 6 CVST patients identified 

following receipt of Janssen’s COVID-19 vaccine. All 6 CVST patients had negative SARS-CoV2 tests; SARS-CoV-2 serology was not documented for patients 1, 3, and 4; patient 2 had 

negative nucleocapsid Ab; and patients 5 and 6 had unspecified COVID Ab negative. The 

hematology test results among the CVST patients showed that all were thrombocytopenic. 

Patients 1, 3, 5, and 6 were severely thrombocytopenic with platelets less than 50,000 per mm3. 

Patient 2 was at 69,000 and Patient 4 at 127,000. The PF4 HIT antibody test results were 

positive for all patients except Patient 1 for whom this test was not done.

In terms of treatment and outcomes among the 6 CVST patients, 4 received heparin. Nonheparin anticoagulants were given in 5 patients, 3 patients got platelets, and 3 patients received 

intravenous immunoglobulin. There was 1 death and based on the most recent information 

available, 3 remain hospitalized with 2 of these in intensive care, and 2 have been discharged 

home.

Regarding some early analyses of observed versus expected CVST cases following Janssen 

COVID-19 vaccine, estimated annual incidence of CVST is approximately 0.5–2 cases per 

100,000 population15. In collaboration with CDC, FDA is working on a more refined analysis in 

which they are looking at individuals who were vaccinated, the dates or approximation of the 

dates of those vaccinations, and calculating individual person time. This should allow them to 

perform a more sophisticated analysis to get more accurate data on observed versus 

suspected. In the interim, they wanted to conduct this analysis. Through a review of the 

literature, the annual incidence of CVST was estimated to be 0.5–2 cases per 100,000 

population. This analysis assumed a risk period of 5.6% of a calendar year. The analytic period 

is from March 2, 2021 through April 12, 2021, which is 41 days. It was assumed that people 

contributed person time for roughly half of that time. It was not known at this stage when people 

were vaccinated or came into the cohort. Therefore, the assumption was made to put it at the 

midpoint and divide the 41 days by 2 to get the person time, which then was divided by 365 

days to annualize that. The doses administered among women 20 to 50 years of age where the 

cases were seen was just over 1.4 million doses. Estimates of reporting ratios were based on 

and estimated annual incidence of 0.5 to 2.0 per 100,000, splitting that out in increments of 0.5. 

Expected cases were then calculated in women 25 to 50 years of age for a reporting ratio of low 

of 3.8 to a high of 15.2. While this is a relatively crude analysis, it demonstrates what is being 

observed versus expected. It is important to note that the CVST cases are based on CVST 

rates in general. CVST in the presence of thrombocytopenia is an even more unusual form of 

15 https://www.hopkinsmedicine.org/health/conditions-and-diseases/cerebral-venous-sinus-thrombosis; 

http://www.med.umich.edu/1libr/Stroke/SinusVeinThrombosis.pdf; 

https://www.nejm.org/doi/10.1056/NEJMra042354?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub; 

https://www.ahajournals.org/doi/pdf/10.1161/STROKEAHA.116.013617; https://www.nature.com/articles/nrneurol.2017.104
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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CVST and there are not enough data to feel very comfortable estimating an incidence for this 

very specific condition in this very specific age and sex group.

To summarize the findings, CVST is rare, but clinically serious, and can result in substantial 

morbidity and mortality. It is not usually associated with thrombocytopenia, so this is unusual. 

The observed cases following Janssen COVID-19 vaccines appear to exceed expected cases 

based on background rates of CVST among women aged 20–50 years by at least 3-fold or 

greater. All 6 reports were in women 18–48 years of age and all had thrombocytopenia. No 

obvious patterns of risk factors have been detected. CVST with thrombocytopenia has not been 

observed after the 2 authorized mRNA vaccines. Just over 182 million mRNA COVID-19 doses 

have been administered with no reported cases of this condition to date. Clinical features of 

Janssen cases are similar to those observed following the AZ COVID-19 vaccine in Europe. 

Both Janssen and AZ vaccines contain replication-incompetent adenoviral vectors—human 

(Ad26.COV2.S) for Janssen and chimpanzee (ChAdOx1) for AZ. The following 

recommendations are included in the HAN for clinicians, public health, and the public:

For Clinicians

1. Pause the use of the J&J COVID-19 vaccine until the ACIP is able to further review 

these CVST cases in the context of thrombocytopenia and assess their potential 

significance.

2. Maintain a high index of suspicion for symptoms that might represent serious thrombotic 

events or thrombocytopenia in patients who have recently received the J&J COVID-19 

vaccine, including severe headache, backache, new neurologic symptoms, severe 

abdominal pain, shortness of breath, leg swelling, petechiae (tiny red spots on the skin), 

or new or easy bruising. Obtain platelet counts and screen for evidence of immune 

thrombotic thrombocytopenia.

3. In patients with a thrombotic event and thrombocytopenia after the J&J COVID-19 

vaccine, evaluate initially with a screening PF4 enzyme-linked immunosorbent (ELISA) 

assay as would be performed for autoimmune HIT. Consultation with a hematologist is 

strongly recommended.

4. Do not treat patients with thrombotic events and thrombocytopenia following receipt of 

J&J COVID-19 vaccine with heparin, unless HIT testing is negative.

5. If HIT testing is positive or unable to be performed in patient with thrombotic events and 

thrombocytopenia following receipt of J&J COVID-19 vaccine, non-heparin 

anticoagulants and high-dose intravenous immune globulin should be strongly 

considered.

6. Report adverse events to VAERS, including serious and life-threatening adverse events

and deaths in patients following receipt of COVID-19 vaccines as required under the 

Emergency Use Authorizations for COVID-19 vaccines.

For Public Health

1. Pause the use of the J&J COVID-19 vaccine in public health clinics until the ACIP is able 

to further review these CVST cases in the context of thrombocytopenia and assess their 

potential significance.

2. Encourage healthcare providers and the public to report all serious and life-threatening 

adverse events and deaths following receipt of COVID-19 vaccines to VAERS as 

required under the EUAs for COVID-19 vaccines.

3. Disseminate this alert to healthcare providers in your jurisdictions.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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For the Public

1. If you have received the J&J COVID-19 vaccine and develop severe headache, 

abdominal pain, leg pain, or shortness of breath within three weeks after vaccination, 

contact your healthcare provider, or seek medical care.

2. Report adverse events following receipt of any COVID-19 vaccine to VAERS.

3. If you are scheduled to receive the J&J vaccine, please contact your healthcare provider, 

vaccination location, or clinic to learn about additional vaccine availability.

Dr. Shimabukuro emphasized the importance of reporting AEs to VAERS, especially these 

clinical serious and unexpected AEs occurring after vaccine. The information for doing so 

follows:

❑ Go to vaers.hhs.gov

❑ Submit a report online

❑ For help:

- Call 1-800-822-7967

- Email info@VAERS.org

- video instructions https://youtu.be/sbCWhcQADFE

He stressed that CDC values the work of HCP on the frontline as partners in vaccine safety and 

views them as the “eyes and ears” to help CDC/FDA detect and rapidly assess potential safety 

problems and make evidence-based public health decisions. It is extremely important for HCP 

who report AEs if contacted and asked by VAERS or CDC to send records to VAERS as soon 

as possible. The Health Insurance Portability and Accountability Act (HIPAA) permits reporting 

of protected health information to public health authorities including CDC and FDA. This is a 

public health function and there should be no concerns about reporting medical records in order 

to allow for an in-depth review of these cases and better understand what is going on with 

vaccine safety.

In terms of next steps, enhanced monitoring will continue in VAERS and other vaccine safety 

systems, such as the Vaccine Safety Datalink (VSD). The VSD contains approximately 113,000 

Janssen doses administered, with 0 cases of CVST in the risk intervals. Potential cases will be 

investigated through detailed clinical reviews and chart reviews, and CDC is in the process of 

assisting FDA to refine the analyses to better quantify risk.

VaST Assessment

Grace M. Lee, MD MPH

VaST Co-Chair

Associate Chief Medical Officer for Practice Innovation

Lucile Packard Children’s Hospital

Professor of Pediatrics, Stanford University School of Medicine

Dr. Lee reminded everyone that the objectives of the COVID-19 VaST Subgroup are to: 1) 

review, evaluate, and interpret post-authorization/approval COVID-19 vaccine safety data; 2) 

serve as the central hub for technical subject matter expertise from federal agencies conducting 

post-authorization/approval safety monitoring; 3) advise on analyses, interpretation, and data 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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presentation; and 4) provide updates to the ACIP COVID-19 Vaccines WG and the ACIP on 

COVID-19 vaccine safety.

VaST has met 30 times in total, including 14 meetings pre-authorization between June 2020-

December 2020 to prepare for vaccine safety surveillance in the US and 16 times between 

December 21, 2020 and the present to review vaccine safety data across multiple surveillance 

systems. As a reminder, ACIP recommended use of the Pfizer/BioNTech mRNA vaccine on 

December 12, 2020; the Moderna mRNA vaccine on December 19, 2020; and the Janssen 

vaccine, the first adenovector vaccine in the US, on February 28, 2021 with the first doses being 

shipped to jurisdictions on March 29, 2021.

To recount the events of the last 48 hours, VaST met to review the data on CVST on April 12, 

2021 from VAERS through April 10, 2021. There were 3 cases following Moderna vaccine at 

that time without thrombocytopenia among 82.6 million doses administered, 0 cases following 

Pfizer-BioNTech vaccine out of 94.7 million doses administered, and 6 cases following the 

Janssen vaccine with thrombocytopenia out of 5.9 million doses administered.

VaST noted that the characteristics of the cases following the Janssen vaccine were similar to 

those following the AZ COVID-19 adenovirus vector vaccine reported from Europe, including 

evidence of thrombosis with thrombocytopenia, elevated D-dimer, and antibodies to PF4 where 

those data were available. These cases also were similar in terms of age group, female 

predominance, and timing of onset within 2 weeks of vaccine receipt. All of the Janssen cases 

occurred in White, non-Hispanic individuals. VaST does not yet have any specific information 

about race/ethnicity in the AZ cases. Other items to note are that the data that VaST reviewed 

focused on the cases, which is numerator only data in order to estimate risks and factors 

associated with CVST with thrombocytopenia. It also is important to understand the 

denominator data, which is forthcoming. This is a quickly evolving situation. It has been only 48 

hours and new details continue to be learned, even during this meeting. Dr. Lee expressed 

gratitude for everyone’s continued vigilance and work in rapidly investigating this potential safety 

signal.

After the April 12, 2021 meeting, the VaST Subgroup discussed these findings in their usual 

independent fashion and expressed several observations based on the review of the data. 

CVST is a rare but SAE following vaccination. The risk factors are not yet well-understood 

based on these case reports. VaST members expressed their concern about delayed 

recognition of this new entity. CVST with thrombocytopenia is fairly unusual. VaST felt strongly 

that early recognition is critical for timely and approach management, including the use of IVIG 

and anticoagulation with non-heparin-based therapies. Vaccine safety is paramount for 

everyone. Global safety monitoring efforts and VAERS enabled the CDC and FDA to rapidly 

detect AEs, which is greatly appreciated in this situation. VaST felt that information about this 

potential life-threatening AE should be provided to clinicians promptly in order to enhance early 

recognition and appropriate treatment of persons who develop thrombosis with 

thrombocytopenia following vaccination. VaST also discussed that further evaluation of the 

benefit-risk balance of using J&J/Janssen vaccine in specific subgroups would be warranted. 

Other vaccines are currently available for use in the US for the prevention of COVID-19. VaST 

recognized that timely and transparent communication with HCP and the public is crucial to 

maintain confidence in the vaccination program. Within 24 hours of that VaST discussion, their 

colleagues at CDC and FDA communicated these findings to providers and the public.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

27

Going forward, VaST plans to focus on enhanced case identification via public health, clinicians, 

and patients, including recent vaccine recipients. Patients will continue to be encouraged to 

enroll in v-safeSM and providers and patients will be encouraged to report to VAERS. VaST will 

continue with its typical investigation process that includes 3 phases. The first phase is signal 

identification, which already has occurred. The second phase is signal refinement, which 

includes a series of steps to evaluate the magnitude and clinical significance of a suspected 

association. The third phase is signal evaluation, which often consists of formal epidemiologic 

analyses to more definitively establish or review causality. The signal refinement phase for 

CVST with thrombocytopenia will include a review of findings in other vaccine safety 

surveillance systems and an assessment of the risk of developing CVST in various subgroups in 

order to inform risk mitigation strategies and support decision-making. VaST will continue to 

review all safety data from the US COVID-19 vaccination program and any data that also are 

made available to them for review outside of the US. VaST also will continue to update the ACIP 

COVID-19 Vaccines WG, ACIP Secretariat, and the full ACIP on a regular basis.

Discussion Points (Lee & Shimabukuro)

Dr. Ault pointed out that ACIP usually does not interact with ED physicians, hematologists, inpatient hospitalists, and several other groups. He asked what was being done to get the word 

out to these types of groups.

Dr. Lee responded that they look to their CDC and partner organization colleagues around the 

table, many of whom communicate with provider communities, as well as their public health 

colleagues who have also issued state HANs to insure that this information expeditiously gets to 

all individuals. She expressed her hope that this open meeting also would help to stimulate the 

necessary attention to ensure that there is timely diagnosis and management of these cases.

Dr. Cohn added that CDC has a Clinician Outreach and Communication Activity (COCA) call 

planned for the next day to do some additional outreach to clinical providers. They also will 

continue to send alerts in CDC’s many emergency response ways to ED providers, primary care 

doctors, and other HCP about what to look for and how to immediately manage any potential 

cases.

Ms. Bahta asked whether the death was associated with and could be attributed to heparin 

treatment, and how widely available the PF4 ELISA test.

Dr. Broder (CISA, ISO) said that they are trying to learn about the unfortunate patient who died. 

They are not in situation where they are looking specifically at the cause of death (COD), which 

they defer to the jurisdictions. In reviewing the cases in general, it does appear that a number of 

cases were initially treated with heparin. That is one of the reasons why the HAN message and 

communication has gone out to ensure that people are aware of this condition and that heparin 

is not to be used unless the HIT testing is negative. Regarding the second question, HIT testing 

is an available test in hospitals, though she was not aware of the nature of the availability in all 

of the regions.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

28

Dr. Bernstein recalled from Dr. Shimabukuro’s presentation that 4 of the 6 CVST patients 

received heparin, but PF4 HIT test results were positive for 5 of the 6 patients.

Dr. Shimabukuro said he thought that this phenomenon occurred prior to the patients being 

treated with heparin. He called upon Dr. Broder to speak more about the mechanism or 

pathophysiology of this condition.

Dr. Broder said it was her understanding that the use of heparin would not trigger a test positive 

immediately. The idea is that this may be a similar mechanism to what Dr. Bell described earlier 

in which the test is positive due to the effects of the vaccine, and that giving heparin may 

exacerbate the situation and make it worse.

Given the effort to study children and de-escalate by age, Dr. Bernstein wondered whether there 

are background rates for CVST in children.

Dr. Shimabukuro said he thinks there are background rates for children, though they were not 

included in his presentation. He would have to get back to the committee on what the rates are 

by age and by sex.

Dr. Bernstein asked whether the 106 AZ cases so far and 6 Janssen cases are attributable to 

the overall number of doses administered, or if there is a difference between chimp and human 

adenovirus.

Dr. Lee the mechanism of action and making sure there is clarity on the denominators in terms 

of who is receiving vaccines are important. The allocation strategies in the US and in other 

countries may mean that the denominators might differ for the individuals who are exposed to 

these vaccines. This is an area for which additional information will be helpful. She emphasized 

that if someone has an anti-PF4 antibody, heparin would not be an appropriate treatment for 

use and other anticoagulation therapies would be indicated if they have the presence of this 

particular antibody. It is not necessarily the exposure to heparin during the admission that is 

creating the positivity. It is an indicator or marker of a potential immune response that is 

facilitating the thrombocytopenia and associated thrombosis. The main point to get across is 

that the diagnostic test is helpful to know whether it is safe to use heparin.

Dr. Long did not think they wanted people to think that the thrombocytopenia is causing the 

clots. It is a risk for bleeding associated with the clots. The part of it that is CVST is seemingly 

special to her with this vaccine. Many people have lots of clots who have platelet antibodies and 

not CVST. With the number of doses administered so far of the Janssen product, it seems 

unlikely that enough time has passed to have reporting of the AEs from the majority or almost all 

of those doses. It is likely that more will be learned in the next 2 to 4 weeks, as well as people 

recognizing that they have cases who did not associate it with the vaccine. The inference of 

white women might also infer that people of color are not at risk, so she wondered whether 

anything is known about the distribution of the vaccine to white women versus non-white 

women.

Dr. Oliver indicated that she would be discussing both of those points during her presentation.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

29

ACIP COVID-19 WG Interpretation

Sara Oliver, MD

LCDR, U.S. Public Health Service

Co-lead, Advisory Committee for Immunization Practices COVID-19 Vaccines WG

COVID-19 Response

Centers for Disease Control and Prevention

Dr. Oliver indicated that in this presentation, she was going to walk through the overall riskbenefit balance for the use of the Janssen COVID-19 vaccine that has been discussed by the 

WG. This includes a review of the CVST cases, the risk of COVID-19 disease by sex and age, 

COVID-19 vaccines administered by age, Janssen vaccine doses administered to date, and 

projected supply of COVID-19 vaccines in the US. The WG also discussed policy options for 

updated recommendations for use of the Janssen COVID-19 vaccine.

The WG reviewed 6 cases of CVST reported to VAERS16, all of which were among women 18-

48 years of age. The interval from vaccine receipt to symptom onset ranged from 6-13 days. 

These cases were described in detail earlier. The WG also discussed the case of CVST 

reported in the Janssen Phase 3 clinical trial in a 25 -year-old male. The Janssen presentation 

described these case details as well. The symptoms developed 9 days after vaccination and on 

Day 21 after vaccination, the patient was diagnosed with CVST was ultimately found to be antiPF4 positive.

In terms of overall COVID-19 epidemiology, the exact risk factors for CVST are unknown. 

Therefore, it is difficult to highlight the epidemiology among the specific population at risk for 

CVST with thrombocytopenia. Therefore, Dr. Oliver discussed the epidemiology by several 

possible factors that could be associated with these cases. Overall for COVID-19 cases by sex 

from January 22, 2020 through April 12, 2021, females represent a slightly higher proportion of 

overall cases and a slightly smaller portion of COVID-19 deaths. The younger age group of 18 

to 29 years represents a higher proportion of COVID-19 cases relative to the percent of the US 

population17. Regarding COVID-19 associated hospitalizations throughout the pandemic, the 

oldest population has represented a larger proportion of hospitalizations throughout the year 

compared to the younger population18. As everyone is aware at this point, the oldest population 

represents a substantial proportion of deaths from COVID-19 relative to the younger 

population19.

Moving to COVID-19 coverage by age, nearly 80% of the oldest population of those 65 years of 

age and older have received at least 1 dose, 40% to 50% of adults 40 to 65 years of age have 

received at least 1 dose, and 25% to 30% of those 18 to 39 years of age have received at least 

1 dose. This highlights the proportion of the population who have yet to be vaccinated with any 

of the COVID-19 vaccinations and to be most impacted by future recommendations20. This 

graphic shows the numbers in millions of doses of adults who are fully, partially, and not 

vaccinated by age group:

16 HAN Archive - 00442 | Health Alert Network (HAN) (cdc.gov) 

17 https://covid.cdc.gov/covid-data-tracker/#demographics (Data from 24,349,551 cases. Age group was available for 24,176,192)

18 https://gis.cdc.gov/grasp/COVIDNet/COVID19_3.html

19 https://covid.cdc.gov/covid-data-tracker/#demographics (Data from 433,171 deaths. Sex was available for 433,132)

20 https://covid.cdc.gov/covid-data-tracker/#vaccination-demographic (Data as of April 13, 2021; age available for 92% of doses 

administered)
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

30

Over 7.2 million doses of the Janssen vaccine have been administered to date. Of those, 

approximately 1.5 million Janssen doses have been administered to females 18-50 years of age 

to date21. To answer one of the questions posed earlier, this table breaks down Janssen vaccine 

doses administered by various populations, from male to female there has been a relatively 

even split by age. Given the time that this vaccine rolled out, only 18% of doses were 

administered to those 65 years of age and older. The majority of doses have been given to 

adults 18 to 50 or 50 to 64 years of age. Race and ethnicity are listed here as well. There is a 

proportion for whom race and ethnicity are not available, but of the doses for which this is 

known, about 60% of doses were administered to White, non-Hispanic individuals.

There was another way that the WG thought through the doses administered. From currently 

available data, the thrombocytopenic thrombotic events developed 6 to 13 days after vaccine 

receipt. It is known that approximately 7.2 doses have been administered to date. Thinking 

through doses since the beginning of the Janssen program in early March through March 30, 

2021, about 3.4 million doses (48%) were administered. With a risk window of up to 2 weeks 

after doses were administered, it is likely that if these vaccine recipients were to develop 

thrombocytopenic thrombotic events post-vaccine, they likely would have already occurred. In 

21 CDC Immunization Data Lake; Includes data reported to CDC as of 4/13/2021 at 6:00 am
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

31

terms of doses administered within the last 2 weeks between March 30 to April 13, 2021, about 

3.7 million doses (52%) had been administered. Therefore, thrombocytopenic thrombotic events 

post-vaccine may still occur after these doses as these individuals still remain within the risk 

window22.

Moving to overall COVID-19 vaccine supply considerations, approximately 14 million first doses 

are expected of Pfizer and Moderna vaccines each week without any substantial interruptions 

anticipated. To date, Janssen COVID-19 vaccine comprises <5% of the vaccines administered. 

However, Janssen vaccine administration began in March 2021 compared to December 2020 

for the mRNA vaccines. Approximately 13 million doses of Janssen vaccines are currently 

available, about 3.6 million doses are available to order, and an estimated 9.2 million doses are 

currently available at administration sites. There may be an additional 11 million doses by the 

end of April 2021. While doses for the Janssen vaccine may be less than for the mRNA 

vaccines overall, the Janssen vaccine occasionally has been used in populations that may be 

difficult to reach with mRNA vaccines that require freezer temperatures or 2 doses.

To summarize what is known so far, thrombocytopenic thrombotic events have occurred after 

receipt of the AZ vaccine. In the US, 6 cases of CVST have been reported after authorization 

and receipt of the Janssen COVID-19 vaccine. No cases of CVST with thrombocytopenia have 

been reported after receipt of either Pfizer and Moderna COVID-19 vaccines. The CVST cases 

have occurred primarily in younger adults and females. CVST can be clinically devastating or 

fatal. In the US, alternative mRNA COVID-19 vaccines are available. Based on current 

projections, supplies of both mRNA vaccines are expected to be relatively stable in the near 

future. Therefore, the decision is not necessarily receipt of the Janssen vaccine versus 

remaining at risk of COVID-19. Instead, the decision may be receipt of a Janssen vaccine 

versus receipt of another mRNA vaccine.

Regarding what is not known, the true background incidence of CVST with thrombocytopenia is 

not known. The specific risk factors for these thrombocytopenic thrombotic events are unknown. 

Also not known is the incidence of other thrombotic, non-CVST cases with thrombocytopenia 

after receipt of the Janssen vaccine. The ability to compare or generalize thrombotic cases after 

the AZ vaccine to Janssen vaccine is unknown. The true incidence of thrombocytopenic 

thrombotic events/CVST after a Janssen COVID-19 vaccine is unknown, and more cases may 

be identified in the coming days to weeks.

Moving to the policy options for use of the Janssen vaccine, the WG had several discussion 

points overall. First, while the reported CVST cases are rare, once limited to doses administered 

to the age and sex of CVST cases seen, the observed cases exceed expected cases. Given the 

timing of doses administered (52% of doses administered in the previous 2 weeks), additional 

cases may be identified over the next 1 to 2 weeks. Finally, the WG emphasized that robust 

safety surveillance is critical. The fact that they are having these discussions so quickly after the 

cases demonstrates that signal detection and evaluation of cases occurred as planned, moving 

to public discussion of these safety issues and policy implications as soon as possible.

There is a spectrum of policy options available for the Janssen vaccine. ACIP could decide that 

the risks outweigh the benefits and vote not to recommend use of the Janssen vaccine due to 

these safety concerns. ACIP also could decide that the benefits outweigh the risks overall and 

recommend use of the vaccine in all adults 18 years of age and older. The WG also discussed 

22 CDC Immunization Data Lake; Includes data reported to CDC as of 4/13/2021 at 6:00 am (Data stratified by age and sex does 

not include Texas) 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

32

something in the middle of this spectrum as well, which would be to recommend use of the 

Janssen vaccine in some populations with age- or gender-specific recommendations such as 

adults 50 years of age and older only or males only.

The WG was concerned that sex/gender-based recommendations would be difficult to 

implement and were not very supportive of this policy option. For age-based recommendations, 

there was concern that there may not be sufficient data at this time to inform a specific age cutoff. However, the WG acknowledged that many countries in Europe have used an age-based 

approach for the AZ vaccine recommendations. Overall, this would allow for the additional 

options of a choice of an mRNA or Ad-vector vaccine in an older population who is at risk for 

COVID-19.

The WG also discussed the possibility of extending the pause while awaiting additional 

information. This potentially could allow for a more informed, specific recommendations for the 

use of the Janssen vaccine. The risk by age could be evaluated to inform a possible age-based 

recommendation. An extended pause also would allow for further assessment to determine 

whether the thrombocytopenic thrombosis risk extends beyond CVST cases. However, 

extension of the pause could have broad consequences. Individuals may want to receive the 

Janssen vaccine. In addition, a pause could have global implications such as pausing clinical 

trials or limiting the availability of Janssen vaccine in other countries with more limited vaccine 

supply.

The WG had a full discussion around these policy options the previous day and favored 

extending the pause for a limited period of time while awaiting additional information. To move 

to specific recommendations, the previous vote to recommend the Janssen vaccine was as 

follows:

The Janssen COVID-19 vaccine is recommended for persons 18 years of age and older 

in the US population under the FDA’s Emergency Use Authorization.

The WG posed the following questions for ACIP to discuss during this meeting:

❑ Does ACIP have enough information to make interim age- or risk factor-based 

recommendations for use of the Janssen vaccine?

❑ What recommendation does ACIP feel is appropriate today given current available 

information for use of the Janssen vaccine?

The WG acknowledged that any recommendations made would be interim and could be 

updated as needed, and that the pause issued by FDA and CDC was only until ACIP had the 

opportunity for discussion during this emergency ACIP meeting. Dr. Oliver thanked the many 

people who helped assemble information for the WG’s meeting the previous day and for this 

emergency ACIP meeting in just a matter of hours. She called upon Dr. Fink from FDA to 

present FDA’s thoughts on this matter prior to opening the discussion to ACIP members.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

33

FDA Perspective 

Doran Fink, MD, PhD

Deputy Director, Clinical, Division of Vaccines and Related Products Applications

Office of Vaccines Research and Review

Center for Biologics Evaluation and Research

Food and Drug Administration

Dr. Fink said that on behalf of FDA, he wanted to thank the ACIP and the COVID-19 Vaccines 

WG for the presentations and for what he was sure would be a thoughtful discussion of this 

safety signal and considerations for that moving forward. As they work to understand the nature 

of this signal, including potential mechanisms and risk factors, FDA will continue to collaborate 

closely with CDC to collect and evaluate information as it becomes available. FDA also will 

continue to collaborate closely with its regulatory and public health counterparts outside of the 

US to leverage their experience with a similar safety signal observed with the AZ vaccine. The 

pause recommended the morning of April 13, 2021 out of an abundance of caution has raised 

national awareness of the safety concern, and has provided time and opportunity to carefully 

and collectively evaluate the information at hand and to formulate questions that remain to be 

addressed.

In FDA’s ongoing assessment of these rare but serous thromboembolic events with 

thrombocytopenia, the current thinking is that this risk could be managed by inclusion of warning 

statements in the EUA Fact Sheets along with coordinated communications from FDA, CDC, 

and others to inform HCP and vaccine recipients of the potential risk and symptoms that should 

warrant medical evaluation, as well as advice to ensure proper diagnosis and management of 

the condition and reporting of any additional cases. With such information available, FDA 

appreciates that individuals, in consultation with their HCP or vaccination providers, may arrive 

at a conclusion of favorable benefit/risk after taking into account demographic factors, risk of 

exposure to SARS-CoV-2, severe outcomes from COVID-19, and access to other authorized 

COVID-19 vaccines. Consequently, this risk management approach could be considered to 

allow for further assessment of the safety signal concurrent with resuming use of the Janssen 

COVID-19 vaccine in individuals or populations for whom the benefits of the vaccine continue to 

outweigh the risks. 

Discussion Points

Dr. Duchin (NACCHO) asked Dr. Shimabukuro if it is possible to have a ballpark estimate of the 

timeframe in which more could be learned about the potential safety signal from non-CVST 

thromboses associated with low platelets to get a better picture of what a potential syndrome 

might be that is associated with this vaccine. Secondly, he wondered if there would be any role 

for v-safeSM in providing any information about this potential issue.

Dr. Shimabukuro said that a timeframe may be difficult to determine because this is such a rare 

condition in general. CDC is reviewing every potential case that comes in. One of the things 

they are looking for in the report and medical records is low platelets. They are able to identify 

cases with and without thrombocytopenia. There also are other AESIs that they plan to assess 

differently, such as PE and VTE. He thinks that now that they are aware of this unusual 

condition of thrombotic events in the presence of thrombocytopenia, they will re-evaluate how 

surveillance will be done to try to get a better idea of what is occurring with these reports. The 

main benefit from v-safeSM may be to get these reports into VAERS. The individuals for these 

specific case reports are quite ill and in the hospital, so they probably are not able to submit a 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

34

report for themselves. The initial presenting symptoms like headache and fatigue are quite 

common and may be less useful. For a rare serious condition like this, VAERS has been 

demonstrated as the system that is going to be able to rapidly detect and evaluate these initial 

reports. He emphasized that their partnership with HCP seeing patients, recognizing potential 

events, reporting, and working with CDC and FDA to access medical records will allow for 

further evaluation of these rare and serious AEs. He stressed that as others had said, this is a 

good example of the system working, how robust the system is, and how the US vaccine safety 

system is able to rapidly detect rare serious events and assess them.

Dr. Drees (SHEA) endorsed what Dr. Lee said earlier that the distribution system for the HAN 

alert is pretty robust and they certainly has communicated that information out to the EDs, 

hematologists, et cetera. Even before the HAN was released, they already were getting 

questions from physicians, patients, EDs, et cetera. They appreciate how quickly the HAN was 

released and the level of clinical detail that was in the HAN. In terms of the availability of the 

heparin-induced antibody testing, her first task when the HAN was received was to figure out 

what this test is and whether they have it in her own institution. While they are a large clinical 

laboratory that is fairly sophisticated, they do not have this test onsite. They send it out, with a 

minimum of a 48-hour turnaround time. She would anticipate that the majority of hospitals in the 

country would have to send out.

Dr. Romero asked whether reference laboratories are able to scale up testing for this if there is 

a surge in requests for it.

Dr. Drees (SHEA) said she did not have the answer for that and did not know how many 

different reference laboratories are typically used by community hospitals, and it is a fairly 

specialized test. She imagines that demand is going to increase quickly.

Dr. Kimberlin (AAP Redbook) noted that there was a key summary on Dr. Shimabukuro’s Slide 

24 that the observed rate was 3-fold or great than the expected rate and requested further 

information about that. 

Referring to Slide 22, Dr. Shimabukuro pointed out that observed in this instance is 6 for 

everything because 6 cases have been observed in the analytic period. The calculations 

involved were then done to estimate the number of expected cases among women 20 to 50 

years of age in the same analytic period. For example, that is basically 6 ÷ 1.58 = 3.8 reporting 

ratio. They did this for different estimated annual instances because there is a range. There are 

at least 3 and possibly up to 15.

Recognizing that CDC and FDA are refining this analysis, Dr. Nirav Shah (ASTHO; State of 

Maine CDC) questioned the choice of denominator for the observed versus expected cases to 

doses among women 20 to 50 years of age. Realizing that epidemiologists often disagree on 

denominator choice, he suggested that it was implausible that the denominator could have been 

all recipients of the vaccine regardless of their age given that there was 1 male with CVST in the 

clinical trials. To the extent the mechanism of action with AZ in Europe is plausibly similar, there 

have been men there who also were affected. Including that and doubling the denominator 

would greatly affect the ratios, so he wondered how they should think about that.

Dr. Shimabukuro said he did not disagree, but they had observed that all cases were in women 

ages 18 to 48 years. Because it appeared to be concentrated in that age group, the decision 

was made that the best analysis would be to look at that denominator. Certainly, they can 

expand on this for future analyses.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

35

Dr. Sanchez commented that there is a positive message that there are 2 vaccines currently 

available in the US that have not been associated with these thrombotic episodes and 

accompanying disorders. He asked whether the cases are being investigated further in terms of 

the adenovirus vector and if there is something unique about this not being seen with the mRNA 

vaccines because of not having the adenovirus vector. For instance, he wondered whether the 

adenovirus vector is being found within the thrombi and/or if there is something different within 

these clots that is different from other cases. He urged further investigation, more autopsy 

specimens, and looking at the thrombi to see if anything can be found that may have been 

triggered by the adenovirus or something else in the vaccine.

Dr. Goldman (ACP) commented that as a practicing internist, he is reassured that the VAERS 

system works and reiterated how important it is for his colleagues on the frontline to be utilizing 

it. He thanked CDC for the HAN as these clinical guidelines help clinicians on the frontline treat 

the patients. Regarding the policy question, as a practicing internist, he favors a pause for the 

immediate future to determine whether more case are reported. The true incidence of this 

condition may be revealed now that so many doses have been administered. Now that he and 

his colleagues are aware of this issue, he suspects that more cases will be reported as it is 

recognized. He also suggested that they consider the risk/benefit of the vaccine compared to 

the risk of getting COVID-19 itself and the potential of deaths from the disease. They may lend 

themselves more toward individuals decisions on which vaccine an individual may choose to 

get, although this could be complicated logistically. In the long-term, he is hopeful that they can 

see if this is an issue with the vaccine adenovirus platform or an issue with this vaccine 

specifically. Regardless, he stressed to the public that they need to remain confident in the 

process and science regarding vaccines in general, and that vaccination against COVID-19 and

many other diseases should continue and not let this sour their decision on getting vaccinated in 

general.

Dr. Romero observed that the data on race and ethnicity is notably weak. As of 3 to 4 weeks 

ago, only 50% of those individuals receiving the vaccine provided information regarding race 

and ethnicity. He cautioned against making any extrapolations based on the data available at 

this time. He pointed out to the voting members of ACIP that they did not have to arrive at a 

recommendation and vote during this meeting. If more information and time are needed to think 

about this, ACIP can reconvene later in the week or during the weekend if necessary. This 

should be a considered vote based on the data ACIP needs. To the general public watching this 

meeting and listening to these presentations, Dr. Romero stressed that it had been stated 

multiple times throughout the meeting that safety has been a paramount issue in ACIP’s 

deliberations for this vaccine recommendation and in following the vaccine. When the 

deliberations on this vaccine began in April 2020, that was foremost on the list of things that 

must be kept in mind and ACIP is doing that at this time. The FDA, CDC, and the 

pharmaceutical companies have stated that safety is the ultimate goal with the vaccine. The fact 

that these very rare clotting incidents have been identified points to the robust safety systems 

that are in place and demonstrates that the US vaccine safety systems are some of the 

strongest in the world. It is important for the public to understand that moving forward with new 

vaccines, there continue to be ongoing safety checks. Regarding the issue of vaccines in 

general and the public, everyone knows there is vaccine hesitancy or reluctance regarding the 

use of these vaccines for the prevention of disease. ACIP needs to come to a decision 

regarding recommendations in a timely manner and ask that if they extend the pause, that the 

pause be sufficient to address the question. This is an issue of safety and risk/benefit analysis. 

All of the questions may not be answered at this time, but a decision must be made in an 

appropriate timeframe. This reminded him of the talk that Dr. Frieden gave when ACIP was 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

36

discussing pneumococcal vaccine. They have the data before them and need to act on those 

data as appropriate and add to those data going forward to modify or strengthen it.

Dr. Frey asked what the WG discussed regarding clotting, DVTs, PEs, et cetera in general with 

or without thrombocytopenia; whether that was taken into consideration; if there is increased 

incidence in clotting without thrombocytopenia; and how that factors into the overall picture. Dr. 

Bell responded that the WG did not focus on that.

Dr. Long stressed that the thrombocytopenia that is so telling here may be only the very severe 

that impacts the cerebral sinuses. The others are much harder to figure out because the 

underlying occurrence is so much higher. It seemed to her that they should be ready to make an 

interim decision to continue the pause for at least a month until they see what else transpires, 

such as whether it occurs in men. In the most recent weeks, increasingly younger individuals 

have been immunized. They might be able to make risk-related, more definitive potential use of 

the vaccine in about a month. It is possible that many more instances will occur in the coming 

month that will help with a more definitive recommendation. She very much favored a continued 

pause and would be opposed to continued use at this time.

Dr. Bernstein requested clarification about Dr. Fink’s statements representing the FDA in terms 

of whether they are suggesting a risk management approach, which incudes warning 

statements. He also wondered what is meant by “warning statements” and how that actually 

would be operationalized in the real world.

Dr. Fink (FDA) indicated that the warning statements he mentioned would be warnings in the 

EUA Fact Sheets for HCP and recipients that are given to vaccine recipients before the vaccine 

is administered. The risk management approach would be in the warning statement in 

combination with other communications from FDA and others.

Dr. Bernstein pointed out that the EUA Fact Sheet is multiple pages as it is and many of the 

people receiving vaccines are not having an opportunity to talk with their own provider about it, 

so there might be a disconnect in some way.

Ms. Bahta said that in reviewing the data, understanding how rare this event is, and based on 

what she had heard in the conversations over the last 24 hours, there are 2 sides to this. One is

that there is over-reacting and the other is that vaccination should be stopped. There has been 

consideration of a provider risk-based discussion about continuing to use the Janssen vaccine 

for those who would feel comfortable. She thought she was coming down on the side of Drs. 

Long and Frey that it would be helpful to have some additional information and that by having 

more robust information, ACIP could be much more confident in how they talk about the safety 

of this vaccine. Right now the confidence for COVID-19 vaccines is right at a precipice. There 

are people who cannot wait to get it and there are others who are waiting and seeing. This will 

contribute to the confidence that people have, so she would be in favor of getting more 

information. 

Dr. Ault asked whether the WG discussed how much longer they would need to acquire this 

information. There is another emergency ACIP meeting scheduled for May 5, 2021. That is 3 

weeks rather than a month from now.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

37

Dr. Bell indicated that there was not a final conclusion about how long would be necessary. 

There was a general sense that there needs to be enough time to provide the kind of data the 

WG felt was necessary, but also that it is extremely important to do this as expeditiously as 

possible because of all of the potential unintended consequences of a prolonged pause.

Dr. Talbot emphasized that fortunately, there are very good, well-proven alternative vaccines in 

the US for which safety signals have not been seen. This puts them in a position to be much 

more cautious and thoughtful and use the old model of “first do no harm.” They should have the 

time to review data on other thrombotic events such as stroke, DVT, and PE. This also is a 

setting in which the usual treatment may be harmful, so they cannot say this is treatable and let 

it go. In addition, insufficient information is known about age at this point. Her suspicion is that 

events like strokes may be under-reported or not flagged and usually occur more often in older 

adults. Therefore, she is hesitant to say that this does not occur in anyone over 50 years of age. 

They should strongly encourage people to continue using the mRNA vaccines that have proven 

to be safe and effective until more is known. If ACIP can say that the Janssen vaccine is 

incredibly safe and they are not worried about risk, they will come back and say that. If not, then 

they have done no harm and have been able to continue vaccinating at this time.

Dr. Sanchez agreed and favored/recommended a continued pause as he was not comfortable 

continuing vaccination with the Janssen product.

Dr. Bell said that to be very frank, she did not want to vote on this issue during this meeting. 

While she also did not want to vote not to recommend the vaccine. They have been looking at 

this issue for less than 2 days and she did not feel that there was sufficient information to make 

an evidence-based decision. While they will not have all of the information, there are some 

things that can be gathered relatively quickly that all have to do with the benefit/risk balance. 

They do need to better understand the risk, which is going to be very low and rare. However, 

they do not know exactly how low, how to characterize it, what the denominator should be, what 

the numerator is, how many cases there are with thrombocytopenia that is not CVST, et cetera. 

In addition, the risk needs to be understood in some kind of context with other things that might 

cause thrombosis for example. It is important for the public to understand what “rare” means 

with respect to other risks that people might take every day. There needs to be a formal 

risk/benefit analysis that allows ACIP to very clearly point out to the American people why ACIP 

thinks that the risk/benefit favors whatever the recommendation is that is made. She wants to 

feel comfortable with her family members and herself to receive this vaccine. Nothing is risk-free 

and as people have said, they are ahead of themselves because this issue was so quickly 

identified and because of what has been going on in Europe. Because she did not want to send 

the message that they were recommending not to take the Janssen vaccine, she thought they 

should not vote and should gather the necessary information to make an evidence-based 

decision.

Dr. Cohn pointed out that while there is a scheduled ACIP meeting for May 5, 2021, if 

information can be assembled before that period, it is not necessary to wait until then to have a 

follow-up discussion.

Dr. Romero emphasized that one option would be to continue the pause until the next meeting

on May 5, 2021 or ACIP could meet sooner if more information becomes available that allows 

them to make a more concrete vote prior to that time. The meeting in 3 weeks would fall within 

the period of a pause and would allow them to gather more data and see if more cases come 

forward.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

38

Ms. McNally agreed that it seemed reasonable to try to collect more data. From the cases that 

were reported directly to Janssen, ultimately those cases were reported to VAERS. She 

wondered if Dr. Shimabukuro could comment on what might be a reasonable period of time to 

gather more data and reevaluate this.

Dr. Shimabukuro indicated that the median onset was 8 days, with a range of 6 to 13 days. 

Individuals have been vaccinated who they would want to follow out for what they think is 

perhaps a reasonable risk window and allow time to actually capture and evaluate any cases 

that might be identified in that risk window of about 1 to 2 weeks. There may be cases that have 

not but might come to CDC’s attention now that this information is known, which is known as a 

reporting bias or stimulated reporting. In the coming weeks, he thinks they will continue to 

gather better and more information as they get access to the medical records. They will refine 

the observed versus expected analysis and will have more and better information to assess the 

signal and possibly characterize the risk.

Dr. Frey asked what the delay is on average for the physician to report information to VAERS 

after an event.

Dr. Shimabukuro indicated that the decision to report occurs at the HCP level. There are 

reporting requirements in EUA, and this would constitute an SAE because the 6 known 

individuals are hospitalized. This would fall under the EUA reporting requirements. CDC’s 

recommendation is to report an AE as soon as possible after the onset of symptoms or after a 

person or HCP becomes aware of the symptoms. They want these reported to VAERS as 

quickly as possible. The other part pertains to how quicky these reports are processed and 

followed-up. Because CDC was following these types of reports closely because of what was 

happening in Europe, CDC is reviewing these events in collaboration with FDA in fairly close to 

real time. The categorization of serious or non-serious is made known to them quickly, so they 

can review the serious reports and identify CVST or other thrombotic events, and expedite 

records collection such that they direct the contractor to expedite collection on a specific report 

or simply do it themselves. They have ways of compressing that timeline and the current focus 

is to make sure that they identify, follow-up, and assess these reports as quickly as possible. On 

CDC’s end, the process is fairly quick and based on the reports that are coming in, providers 

are reporting them in a timely manner as well.

Dr. Lee said that having had only about 48 hours to think about this, she wanted to make a few 

statements and put out a few requests. Everyone acknowledges that risk is an inherent part of 

life. They would not be vaccinating anyone if there were not a COVID-19 panic right now. There 

is a population level benefit/risk balance and an individual risk/benefit balance that need to be 

considered at this point. She thinks the role of ACIP in this instance is to focus on mitigating that 

risk and to better understand the benefits. She also has seen patients admitted with clotting 

disorders and thrombocytopenia—some type of immune-mediated thrombocytopenia 

associated with COVID-19 disease. From the ACIP perspective, she thinks there are 3 things 

they can do to mitigate risk. One is to identify populations at the highest risk for this potential 

complication and adapt the recommendations to minimize exposures for them. The second is to 

educate patients about the benefits and risks of different vaccines, and to ensure that patients 

seek care in a timely manner. The third is ensuring that healthcare systems are able to 

diagnose and manage these cases in an incredibly timely way. If these cases can be managed 

early and well similar to anaphylaxis, it may be possible to employ strategies that change the 

outcomes that are seen with these patients. That said, this is challenging because ACIP 

decisions have to be based on the global stage. This is clear to her given their past experience 

with rotavirus vaccines. The benefit risk/balance may be very different in other countries where 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

39

vaccines are either not available or are not feasible for widespread implementation. She 

recognized that ACIP’s responsibilities are to individuals in the US, but she also feels the weight 

of the burden of the global responsibility that they also have and the impact that that their 

decision-making potentially could worsen inequities. Regardless of the decision they make on 

this particular safety signal, it is important to ensure that they are collaborating with partners 

outside the US to address those inequities in whatever ways they can. In terms of thinking about 

what information is needed before she thinks a vote can be taken, she did not think they had 

enough information at this point and need to go through the signal refinement phase in order to 

capture age and gender stratified rates of CVST and the associated outcomes among both 

vaccinees and those with COVID-19 disease so they have a better understanding of risk factors 

associated with CVST and those who have poor outcomes associated with CVST. They need to 

review the data across multiple vaccine safety surveillance systems. She wholeheartedly 

agreed that a formal benefit/risk assessment is needed to make well-informed decisions. They 

need to move through the safety signal refinement phase as quickly as possible in order to be 

able to support evidence-based decision-making. They also need strong collaboration across 

federal agencies and with global partners in order to make the best possible decision in as 

timely a manner as possible. She continues to feel that they are in a race against time and the 

variants, but that they need to do so in the safest possible way.

Dr. Kotton very much agreed with Dr. Lee and added that putting this vaccine on pause for 

those who are frontline healthcare workers (HCW) has been devastating. She agreed in general 

that there is not enough data to make a decision at this time, but the State of Massachusetts 

was planning to use this vaccine for people who are homebound and otherwise not able to get a 

vaccine, vulnerable inpatient populations who often have multiple comorbidities and are often at 

high risk of disease but have not been able to get vaccinated, otherwise under-served 

populations, and populations who are not able to get mRNA vaccines. She definitely wants them 

to be cautious and careful with their decision-making, but also emphasized that loss of this oneand-done vaccine that did not require the cold-chain that the mRNA vaccines do is significant.

Dr. Cohn summarized what she had heard thus far and offered some potential options moving 

forward. They certainly heard that there is a need for more refinement of the risk and of the 

risk/benefit analyses. She reminded everyone that the goal for this meeting was for CDC to be 

as transparent as possible and communicate information as rapidly as it was available to ACIP 

members, liaisons organizations, and the public knowing that they will be doing some of this 

work around the clock over the next several days. They are working on these analyses. The 

question at this time pertained to whether ACIP is comfortable continuing the pause and not 

making any decisions at this time, or if the committee preferred to make a recommendation 

around shifting the pause for a short basis just in a certain population versus the entire 

population that is currently paused. The interim shift can be for just a week or two as they try to 

refine. Typically when ACIP makes interim recommendations they are thinking for longer 

periods of time, but there are various options including just waiting for more information. The 

critical question regards whether the pause should continue for the whole population versus 

refining that.

Speaking in his capacity as President of ASTHO and Director of the State of Maine CDC, Dr. 

Shah (ASTHO) expressed concern about the direction he feared the committee may be going. 

They are in a situation where not making a decision is tantamount to making a decision. Any 

extension of the pause will invariably result in the fact that the most vulnerable individuals in the 

US who are prime candidates for the Janssen vaccine will remain vulnerable, the most at risk 

will remain at risk, and those who would benefit immediately from vaccination will remain 

unvaccinated for an unknown period of time that would occur during a period when the US 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

40

logged 5000 deaths and 489,000 new cases across the country in the past 7 days. The initial 

reason for the pause among others was to ensure that HCP and recipients were apprised of the 

possible risks as well as to be on the lookout for them so appropriate treatment could be given. 

It is always possible to get more data and, indeed, in the history of pharmaceuticals, the 

understanding of risk is always being refined. There are also tools available to better evaluate 

and mitigate that risk while continuing provision of the Janssen vaccine. He urged that any 

pause be counterbalanced by consideration of the equity consideration that would befall from 

any lengthening of the pause.

Dr. Fryhofer (AMA) said that speaking as an individual practicing physician, the whole process 

during this meeting increased her confidence in vaccine safety. She greatly appreciated the 

honesty, transparency, and quick action that the FDA and CDC have taken. She listened to the 

comments from their esteemed group of ACIP members and expressed her personal hope that 

they would support a pause sufficient to determine whether this is a “needle in a haystack” or 

the “tip of an iceberg.” Other vaccines are available and there is a supply of them. She is 

sensitive to the equity of vaccine distribution and knows that many patients have not been able 

to get vaccinated, but they want to make sure the vaccines are safe. A short pause will give 

them a chance to collect this information and give physicians and patients time to understand 

the issues. She emphasized that she respects the process and is proud to be a part of it.

Dr. Talbot said she appreciates the comments about giving vaccine to those who are 

homebound and difficult to find. However, she also is worried that those who cannot get to 

medical care and those who are difficult to find also may be at risk for severe clotting if they do 

develop this and do not get to care in sufficient time. It is a double-edged sword, which is why 

the risk/benefit analysis will help figure this out.

Dr. Duchin (IDSA) emphasized for the public that what they are talking about is a very rare 

albeit serious event that is associated with a vaccine that was detected through the vaccine 

safety systems. If the ACIP elects to pause further, it should not be interpreted as a signal that 

there is an increased concern about vaccine safety at this point beyond which was evident 

initially. Instead, this is a desire to better characterize the risk in order to make the best possible 

guidance going forward.

Dr. Long said that they did not really answer Dr. Cohn’s question about whether any less/more 

at risk groups could be parsed out rather than a universal pause. She thought ACIP would be 

uncomfortable with that due to the lack of specific and large data that would help them decide 

what person is more or less at risk. While the risk is very small, it is very serious. There could be 

severe consequences for people’s lives, so she thought they could live with the unintended 

consequences of extending the pause because of the amount of vaccine that is available. It 

would be sending the wrong message to the people who would be getting this. She favored 

continuing the pause until better data are available.

Dr. Lee stressed that they all care very much about safety and individual and population 

risk/balance. She did not think an indefinite pause would be good and as Dr. Shah pointed out is 

functionally a decision. The main question regards whether they can assess where they are in a 

week or two. Even in the last 24 hours, a tremendous amount of data have come out.

Dr. Cohn completely agreed that they did not want for it to feel like an indefinite pause. From a 

process perspective, if ACIP did not have a motion or desire to vote on a recommendation 

during this meeting, that would result in going back to work as quickly as possible and 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

41

scheduling an additional emergency meeting in a week to 10 days at which time as much 

information as possible would be presented.

Dr. Bell stressed that she did not want to send the message that there is some huge concern of 

a different order of magnitude than any other vaccine safety signals they evaluate, or that there 

is something fundamentally wrong with this vaccine. Whatever the process is that would allow 

them to have enough information as expeditiously and quickly as possible, which is never all of 

the information, but hopefully will be some of the items mentioned as important and necessary, 

she would support. This is a very rare event, nothing in life is free, but she wants to be able to 

understand and defend the decision that she has made based on a reasonable amount of data.

Dr. Ault agreed that there should not be an indefinite pause and was reassured hearing that this 

could be a relatively short amount of time.

Dr. Bernstein agreed that this should not be an indefinite pause. He expressed interest in 

knowing how many Janssen vaccinees they could expect to have data from and in what time 

looking forward over the next 1 to 3 weeks.

Dr. Oliver indicated that 3.8 million doses were administered in the last 2 weeks, but did not 

have a further breakdown on each week. They expect some stimulated reporting as Dr. 

Shimabukuro noted now that the information has been communicated and they are highlighting 

cases and asking for reports. They would expect a much faster turnaround between 

presentation and diagnosis and then diagnosis to reporting to VAERS now that the HAN and 

other educational messages have been disseminated.

Dr. Shah (ASTHO) expressed concern on this line of discussion. While he understood the 

rationale behind the pause but thought that they also should have a theory of lifting the pause. If 

the concept of operations right now is simply to accrue more data without a theory of what those 

data may mean and how they might be evaluated, it is just as possible that the committee may 

continue the pause in the 3 weeks to wait for even more data. If they are going to continue the 

pause, they should at least couple that with a theory of what lifting the pause may look like and 

under what criteria they would do so.

Dr. Lee said that to her, it was not about having perfect data because they will never have this 

and there always will be uncertainty. Instead, it was about getting better risk estimates and 

understanding how to minimize exposure to those who may be at highest risk for this particular 

AE. It is possible there may not be any further information, in which case ACIP will still have to 

make a decision or recommendation at that time. Her hope is that in the next week or two, this 

can be captured in a more robust way. The benefit/risk balance to her remains unclear without 

having a risk estimate of this particular potential AE by age, gender, and other risk factors that 

may contribute. She agreed that ACIP needs to make a recommendation soon.

Dr. Romero summarized that ACIP was not ready to vote at this time. Dr. Cohn added that she 

was hearing from the ACIP members and liaisons is that there is a strong desire to reconvene 

as quickly as possible after a risk/benefit analysis and risk refinement have been done, which 

CDC committed to doing as rapidly as possible. At this time, ACIP does not wish to vote or put 

any motions on the table to vote for a change in the current recommendation. Instead, the 

pause would continue on the current recommendation. That is, ACIP would be providing no 

recommendation to the CDC Director until they meet again in a week to 10 days. There was no 

ACIP opposition to this. CDC will try to identify the next meeting date by Friday, April 16, 2021.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

42

Public Comments

José Romero, MD, FAAP

ACIP Chair

Dr. Romero opened the floor for public comment during the April 14, 2021 ACIP emergency 

meeting at 4:20 PM ET. He welcomed and thanked the public speakers for addressing ACIP 

and emphasized that ACIP takes public comments very seriously. Given the limited timeframe 

available, speakers were requested to limit their remarks to the 3 minutes allotted. All speakers 

submitted a request in advance of the meeting, with the final selection of public commenters 

made randomly via a lottery. The comments made during the meeting are included here. 

Members of the public also were invited to submit written public comments to ACIP through the 

Federal eRulemaking Portal under Docket No. CDC-2021-0042. Visit http://www.regulations.gov

for access to the docket or to submit comments or read background documents and comments 

received.

Richard Junghans, MD, PhD

Associate Professor

Boston University School of Medicine

President, IT Bio, LLC 

My name is Dr. Richard Junghans. I am an Immunotherapist and Hematologist-Oncologist who 

trained with Thomas Waldmann at the National Cancer Institute (NCI). I am an Associate 

Professor at Boston University School of Medicine (BUSM) and President of IT Bio, LLC, an 

immunotherapy company in Cambridge. A start-up I should say. I have a technical comment 

about the anti-platelet antibody, so if I have time at the end, I’ll move to that. But I want to jump 

into what I consider the “elephant in the room.” That is, prior infectees, people who have been 

infected previously, I contend have a superior immunity than any conferred by these very good 

vaccines. If I’m right, then we’re subjecting patients to risk unnecessarily, however small these 

risks are which are being addressed today, and also wastes drugs that could have been used to 

save other people’s lives already who waited in line for those who didn’t need it. The policies I’d 

like to see changed would be to accord infectees the same status as vaccinees officially by 

CDC, which serves as an example around the world. This would be for so-called immunity 

passports, jobs, travel, et cetera. Exempt them from vaccination requirements at some jobs that 

have been put in place. Any prior test by polymerase chain reaction (PCR), antigen, or antibody 

would be accepted. Antibody waning doesn’t concern me because neutralizing antibodies are 

not judged by this assay as proven in the initial Chinese study that focused on total antibody 

waning, but was the wrong focus—neutralizing antibodies predicted to persist for years. 

Antibodies aren’t critical anyway. T-cells are the main bullwork of the immunity. This is seen in 

agammaglobulinemia where patients don’t get sick from bad viral infections. They get sick from 

bacterial infections. Proof that infection is better is quickly available. Look at the Pfizer vaccine 

study: 20,000 patients per arm; 160 in the control arm got infected; 8 in the vaccine arm got 

infected. To compare that 20,000 to 20 million patients who are documented to have recovered 

from COVID—that would predict 8000 second infections. It’s been hard for people to find even a 

dozen such cases. CDC estimates a 4.6:1 ratio of people infected to those who actually have 

tested positive. That would mean 138 million people have been infected out of 210 million. I 

would like to say that I’ll be posting this material.
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Del Bigtree

CEO, Informed Consent Action Network 

Host, The HighWire

My name is Del Bigtree. I am the CEO of the Informed Consent Action Network (ICAN). I’m the 

host of the internet talk show, The HighWire. I am formerly Producer of the CBS talk show, The 

Doctors, where I won an Emmy Award celebrating the best that science and medicine have to

offer. I have been attending the meetings of the Advisory Committee on Immunization Practices 

for over 3 years now. I have spoken many, many times during public comment. I have done 

several of these now over the computer. I have been saying and trying to make the same point 

for some time now. You at the CDC and the Advisory Committee need to start taking much 

more seriously the visibility of the work that you’re doing and the promotion and the PR around 

it. I have been warning you that you cannot continue to keep promoting products like vaccines 

made by Johnson & Johnson that have not been properly tested for long-term issues or even 

short-term issues in the clinical trials. We are talking about a company that has paid out billions 

of dollars for lying about safety. They lied about the oxycontin epidemic and yet you at the 

Advisory Committee and at the CDC now find yourselves in an incredible situation, and it’s 

something that I have been warning you about. Confidence in this vaccine program and now the 

CDC is in grave, grave danger. We now have a vaccine that is just like the AstraZeneca vaccine 

in Europe and I’m honestly questioning the CDC. Are you going to make the same mistake that 

the European Medicines Agency (EMA) in Europe made and try to cover this up and say, “Oh, 

it’s gonna be just fine” only to have to retract that a couple of weeks later. Now we have nations 

like Denmark withdrawing the AstraZeneca vaccine because their own science shows that this 

issue is happening in 1 in 40,000 people. What will be the plan? The CDC, if it wants to hold on 

to any credibility right now, you know, and risk not only a loss of confidence in our healthcare 

system and the CDC, but maybe the science as we know it. I urge you, please withdraw 

Johnson & Johnson completely. Europe is now overwhelmed. The United Kingdom’s (UK’s) 

hospitals are overwhelmed by people that are panicking even from mild symptoms. Our 

hospitals can’t afford this. This mistake is only going to get worse and worse. We have a few 

other vaccine options. Please, do the CDC a favor. Do the nation a favor and lead by erring on 

the side of caution for the citizens and not the pharmaceutical industry and pull Johnson & 

Johnson immediately or we could seriously see the disruption of confidence in all vaccine 

programs and science as we know it. This is what is now sitting in your hands. Thanks. I hope 

this time you will finally hear my plea.

Marla Dalton, PE, CAE

Executive Director & CEO

National Foundation for Infectious Diseases

Thank you and good afternoon. I am Marla Dalton, Executive Director & CEO of the National 

Foundation for Infectious Diseases (NFID). On behalf of NFID as a longstanding partner of 

CDC, we appreciate the valuable work of ACIP and the robust United States (US) vaccine 

safety surveillance systems in place. Monitoring the safety of vaccines is an ongoing process. 

The decision by the Food and Drug Administration (FDA) and CDC to review reports of a rare 

blood clotting condition among some recipients of COVID-19 vaccines demonstrates the strong 

US commitment to vaccine safety. To date, there have been 6 reported cases of blood clotting 

among the approximately 7 million doses of the Johnson & Johnson COVID-19 vaccine 

administered in the US, clearly demonstrating the sensitivity of the vaccine safety system in 

place. The fact that public health officials have paused administration of the vaccine to 

investigate these reports is reassuring to all of us who are committed to vaccine safety. We at 

NFID stand ready to help communicate the results of the data analysis and any implications for 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

44

public policy. The actions taken by CDC and FDA also illustrate some of the core principles of 

communicating about COVID-19, which are outlined in a new NFID report23, “COVID-19 

Communications: Promoting Prevention Measures and Vaccine Confidence.” The report, which 

was developed with input from more than 50 leading organizations and multidisciplinary experts 

is now available on the NFID website at nfid.org. As the science and knowledge around COVID19 continue to evolve, being open and transparent about what we know and what we do not yet 

know helps all to manage expectations and reduce anxiety and confusion about vaccines and 

other COVID-19 prevention measures. The work of ACIP in guiding US immunization policy and 

overseeing vaccine safety is vital to protecting public health. On behalf of NFID, thank you all for 

your dedicated service.

23 https://www.nfid.org/infectious-diseases/covid-19-communications/
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

45

Upon reviewing the foregoing version of the April 14, 2021 ACIP meeting minutes, Dr. Jose 

Romero, ACIP Chair, certified that to the best of his knowledge, they are accurate and 

complete. His original, signed certification is on file with the Management Analysis and Services 

Office (MASO) of CDC.

Certification
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

46

Department of Health and Human Services 

Centers for Disease Control and Prevention 

Advisory Committee on Immunization Practices 

December 23, 2020 – June 30, 2021 

CHAIR

ROMERO, José R, MD, FAAP 

Arkansas Secretary of Health 

Director, Arkansas Department of Health 

Professor of Pediatrics, Pediatric Infectious Diseases 

University of Arkansas for Medical Sciences 

Little Rock, Arkansas 

Term: 10/30/2018-06/30/2021 

EXECUTIVE SECRETARY

COHN, Amanda, MD 

Senior Advisor for Vaccines 

National Center for Immunization and Respiratory Diseases 

Centers for Disease Control and Prevention 

Atlanta, GA 

MEMBERS

AULT, Kevin A, MD, FACOG, FIDSA 

Professor and Division Director 

Department of Obstetrics and Gynecology University of 

Kansas Medical Center 

Kansas City, KS 

Term: 10/26/2018 – 6/30/2022 

BAHTA, Lynn, RN, MPH, CPH 

Immunization Program Clinical Consultant 

Infectious Disease, Epidemiology, Prevention & Control Division 

Minnesota Department of Health 

Saint Paul, Minnesota 

Term: 7/1/2019 – 6/30/2023

BELL, Beth P, MD, MPH 

Clinical Professor 

Department of Global Health, School of Public Health 

University of Washington 

Seattle, WA 

Term: 7/1/2019 – 6/30/2023 

ACIP Membership Roster
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

47

BERNSTEIN, Henry, DO, MHCM, FAAP 

Professor of Pediatrics 

Zucker School of Medicine at Hofstra/Northwell 

Cohen Children’s Medical Center 

New Hyde Park, NY 

Term: 11/27/2017-06/30/2021 

CHEN, Wilbur H, MD, MS, FACP, FIDSA 

Professor of Medicine 

Center for Vaccine Development and Global Health 

University of Maryland School of Medicine 

Baltimore, MD 

Term: 12/23/2020 – 6/30/2024 

DALEY, Matthew F, MD 

Senior Investigator 

Institute for Health Research, Kaiser Permanente Colorado 

Associate Professor of Pediatrics 

University of Colorado School of Medicine 

Aurora, CO 

Term: 1/4/2021 – 6/30/2024 

FREY, Sharon E, MD 

Professor and Associate Director of Clinical Research 

Clinical Director, Center for Vaccine Development 

Division of Infectious Diseases, Allergy and Immunology 

Saint Louis University Medical School 

Saint Louis, MO 

Term: 11/27/2017-06/30/2021 

KOTTON, Camille Nelson, MD, FIDSA, FAST 

Clinical Director, Transplant and Immunocompromised Host Infectious Diseases 

Infectious Diseases Division, Massachusetts General Hospital 

Associate Professor of Medicine, Harvard Medical School 

Boston, MA 

Term: 12/23/2020 – 6/30/2024 

LEE, Grace M, MD, MPH 

Associate Chief Medical Officer for Practice Innovation 

Lucile Packard Children’s Hospital 

Professor of Pediatrics, Stanford University School of Medicine 

Stanford, CA 

Term: 7/1/2016 – 6/30/2021 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

48

LONG, Sarah S, MD 

Professor of Pediatrics 

Drexel University College of Medicine 

Section of Infectious Diseases 

St. Christopher’s Hospital for Children 

Philadelphia, Pennsylvania 

Term: 12/24/2020 – 6/30/2024 

MCNALLY, Veronica V, JD 

President and CEO Franny 

Strong Foundation 

West Bloomfield, Michigan 

Term: 10/31/2018 – 6/30/2022 

POEHLING, Katherine A, MD, MPH 

Professor of Pediatrics and Epidemiology and Prevention 

Director, Pediatric Population Health 

Department of Pediatrics 

Wake Forest School of Medicine 

Winston-Salem, NC 

Term: 7/1/2019 – 6/30/2023 

SÁNCHEZ, Pablo J, MD 

Professor of Pediatrics 

The Ohio State University – Nationwide Children’s Hospital 

Divisions of Neonatal-Perinatal Medicine and Pediatric Infectious Diseases 

Director, Clinical & Translational Research (Neonatology) 

Center for Perinatal Research 

The Research Institute at Nationwide Children's Hospital Columbus, Ohio 

Term: 7/1/2019 – 6/30/2023 

TALBOT, Helen Keipp, MD 

Associate Professor of Medicine 

Vanderbilt University 

Nashville, TN 

Term: 10/29/2018 – 6/30/2022 

EX OFFICIO MEMBERS 

Centers for Medicare and Medicaid Services (CMS)

HANCE, Mary Beth 

Senior Policy Advisor 

Division of Quality, Evaluations and Health Outcomes 

Children and Adults Health Programs Group 

Center for Medicaid, CHIP and Survey & Certification Centers 

for Medicare and Medicaid Services Baltimore, MD 
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Food and Drug Administration (FDA) 

FINK, Doran, MD, PhD 

Deputy Director, Clinical, Division of Vaccines and Related Products Applications 

Office of Vaccines Research and Review 

Center for Biologics Evaluation and Research 

Food and Drug Administration 

Silver Spring, MD 

Health Resources and Services Administration (HRSA) 

RUBIN, Mary, MD 

Chief Medical Officer 

Division of Injury Compensation Programs 

Rockville, MD 

Indian Health Service (IHS) 

WEISER, Thomas, MD, MPH 

Medical Epidemiologist 

Portland Area Indian Health Service 

Portland, OR 

Office of Infectious Disease and HIV/AIDS Policy (OIDP)

KIM, David, MD, MA 

Director, Division of Vaccines, OIDP 

Office of the Assistant Secretary for Health 

Department of Health and Human Services 

Washington, DC 

National Institutes of Health (NIH) 

BEIGEL, John, MD 

Associate Director for Clinical Research 

Division of Microbiology and Infectious Diseases 

National Institute of Allergy and Infectious Diseases (NIAID) Bethesda, MD 

LIAISON REPRESENTATIVES 

American Academy of Family Physicians (AAFP)

ROCKWELL, Pamela G, DO 

Associate Professor, Department of Family Medicine, University of 

Michigan Medical School 

Medical Director, Dominos Farms Family Medicine 

Ann Arbor, MI 

American Academy of Pediatrics (AAP) 

MALDONADO, Yvonne, MD 

Senior Associate Dean for Faculty Development and Diversity 

Professor of Pediatrics and Health Research and Policy 

Chief, Division of Pediatric Infectious Diseases 

Stanford University School of Medicine Stanford, CA 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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American Academy of Pediatrics (AAP) 

Red Book Editor

KIMBERLIN, David, MD 

Professor of Pediatrics 

Division of Pediatric Infectious Diseases 

The University of Alabama at Birmingham School of Medicine Birmingham, AL 

American Academy of Physician Assistants (AAPA) 

LÉGER, Marie-Michèle, MPH, PA-C 

Senior Director, Clinical and Health Affairs 

American Academy of Physician Assistants Alexandria, VA 

American College Health Association (ACHA) 

CHAI, Thevy S., MD 

Director of Medical Services 

Campus Health Services 

University of North Carolina at Chapel Hill Chapel Hill, 

NC 

American College Health Association (ACHA) (alternate) 

MCMULLEN, Sharon, RN, MPH, FACHA 

Assistant Vice President of Student & Campus Life for Health and Wellbeing Cornell Health 

Ithaca, NY 

American College of Nurse Midwives (ACNM) 

HAYES, Carol E., CNM, MN, MPH 

Lead Clinician 

Clinical Quality Compliance and Management 

Planned Parenthood Southeast Atlanta, GA 

American College of Nurse Midwives (ACNM) (alternate) 

MEHARRY, Pamela M., PHD, CNM 

Midwifery Educator, Human Resources for Health 

In partnership with University of Rwanda and University of Illinois, Chicago 

American College of Obstetricians and Gynecologists (ACOG) 

ECKERT, Linda O, MD, FACOG 

Professor, Department of Obstetrics & Gynecology 

Adjunct Professor, Department of Global Health 

University of Washington 

Seattle, WA

American College of Physicians (ACP) 

GOLDMAN, Jason M, MD, FACP 

Affiliate Assistant Professor of Clinical Biomedical Science, Florida Atlantic University, Boca 

Raton, Florida 

Private Practice 

Coral Springs, FL 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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American Geriatrics Society (AGS) 

SCHMADER, Kenneth, MD 

Professor of Medicine-Geriatrics Geriatrics 

Division Chief 

Duke University and Durham VA Medical Centers 

Durham, NC 

America’s Health Insurance Plans (AHIP) 

GLUCKMAN, Robert A, MD, MACP 

Chief Medical Officer, Providence Health Plans 

Beaverton, OR 

American Immunization Registry Association (AIRA) 

COYLE, Rebecca, MSEd 

Executive Director, AIRA Washington, DC 

American Medical Association (AMA)

FRYHOFER, Sandra Adamson, MD 

Adjunct Associate Professor of Medicine Emory 

University School of Medicine 

Atlanta, GA 

American Nurses Association (ANA) 

RITTLE, Charles (Chad), DNP, MPH, RN Assistant 

Professor, Nursing Faculty 

Chatham University, School of Health Sciences 

Pittsburgh, PA 

American Osteopathic Association (AOA) 

GROGG, Stanley E, DO 

Associate Dean/Professor of Pediatrics 

Oklahoma State University-Center for Health Sciences 

Tulsa, OK 

American Pharmacists Association (APhA) 

FOSTER, Stephan L, PharmD CAPT 

(Ret) USPHS 

Professor, College of Pharmacy 

University of Tennessee Health Sciences Center 

Memphis, TN 

Association of Immunization Managers (AIM) 

HOWELL, Molly, MPH 

Immunization Program Manager 

North Dakota Department of Health

Bismarck, ND 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Association for Prevention Teaching and Research (APTR) 

McKINNEY, W Paul, MD 

Professor and Associate Dean 

University of Louisville School of Public Health and Information Sciences

Louisville, KY 

Association of State and Territorial Health Officials (ASTHO) 

SHAH, Nirav D, MD, JD 

Director

Maine Center for Disease Control and Prevention

Augusta, ME 

Biotechnology Industry Organization (BIO) 

ARTHUR, Phyllis A, MBA 

Senior Director, Vaccines, Immunotherapeutics and Diagnostics Policy 

Washington, DC 

Council of State and Territorial Epidemiologists (CSTE) 

HAHN, Christine, MD 

State Epidemiologist 

Office of Epidemiology, Food Protection and Immunization Idaho 

Department of Health and Welfare 

Boise, ID 

Council of State and Territorial Epidemiologists (CSTE) (alternate) 

LETT, Susan, MD, MPH 

Medical Director, Immunization Program 

Division of Epidemiology and Immunization 

Massachusetts Department of Public Health 

Boston, MA 

Canadian National Advisory Committee on Immunization (NACI) 

QUACH, Caroline, MD, MSc 

Pediatric Infectious Disease Specialist and Medical Microbiologist 

Medical Lead, Infection Prevention and Control Unit 

Medical Co-director – Laboratory Medicine, Optilab 

Montreal-CHUM 

Montreal, Québec, Canada 

Infectious Diseases Society of America (IDSA) 

BAKER, Carol J., MD 

Professor of Pediatrics 

Molecular Virology and Microbiology 

Baylor College of Medicine 

Houston, TX 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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International Society for Travel Medicine (ISTM) 

BARNETT, Elizabeth D, MD Professor of 

Pediatrics 

Boston University School of Medicine 

Boston, MA 

National Association of County and City Health Officials (NACCHO)

ZAHN, Matthew, MD 

Medical Director, Epidemiology 

Orange County Health Care Agency 

Santa Ana, CA 

National Association of County and City Health Officials (NACCHO) (alternate)

DUCHIN, Jeffrey, MD 

Health Officer and Chief, Communicable Disease

Epidemiology and Immunization Section 

Public Health - Seattle and King County 

Professor in Medicine 

Division of Allergy and Infectious Diseases 

University of Washington School of Medicine and School of Public Health

Seattle, WA 

National Association of Pediatric Nurse Practitioners (NAPNAP) 

STINCHFIELD, Patricia A, RN, MS, CPNP 

Director 

Infectious Disease/Immunology/Infection Control

Children's Hospitals and Clinics of Minnesota 

St. Paul, MN 

National Foundation for Infectious Diseases (NFID) 

SCHAFFNER, William, MD 

Chairman, Department of Preventive Medicine 

Vanderbilt University School of Medicine 

Nashville, TN 

National Foundation for Infectious Diseases (NFID) (alternate)

DALTON, Marla, PE, CAE 

Executive Director & CEO 

National Foundation for Infectious Diseases (NFID) 

Bethesda, MD 

National Medical Association (NMA) 

WHITLEY-WILLIAMS, Patricia, MD Professor and Chair 

University of Medicine and Dentistry of New Jersey Robert Wood 

Johnson Medical School 

New Brunswick, NJ 
Advisory Committee on Immunization Practices (ACIP) Summary Report April 14, 2021

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Pediatric Infectious Diseases Society (PIDS) 

O’LEARY, Sean, MD, MPH 

Associate Professor of Pediatrics 

Pediatric Infectious Diseases 

General Academic Pediatrics 

Children’s Hospital Colorado 

University of Colorado School of Medicine 

Pediatric Infectious Diseases Society (PIDS) (alternate)

SAWYER, Mark H, MD 

Professor of Clinical Pediatrics 

University of California, San Diego School of Medicine 

San Diego, CA 

Pharmaceutical Research and Manufacturers of America (PhRMA) 

ROBERTSON, Corey, MD, MPH 

Senior Director, US Medical, Sanofi Pasteur 

Swiftwater, PA 

Society for Adolescent Health and Medicine (SAHM) 

MIDDLEMAN, Amy B, MD, MSEd, MPH 

Professor of Pediatrics 

Chief, Section of Adolescent Medicine 

University of Oklahoma Health Sciences Center

Oklahoma City, OK 

Society for Healthcare Epidemiology of America (SHEA)

DREES, Marci, MD, MS 

Chief Infection Prevention Officer & Hospital Epidemiologist 

ChristianaCare 

Wilmington, DE 

Associate Professor of Medicine 

Sidney Kimmel Medical College at Thomas Jefferson University Philadelphia, PA