For more information: www.cdc.gov/COVID19

Thrombocytopenic thrombosis after 

Janssen vaccine:

Work Group Interpretation

ACIP COVID-19 Vaccines

Sara Oliver MD, MSPH

ACIP Meeting

April 14, 2021
2

Discussion by the Work Group

 Benefit/risk balance for use of the Janssen COVID-19 vaccine

 Review of cerebral venous sinus thrombosis (CVST) cases

 Risk of COVID-19 disease, by sex and age

 COVID-19 vaccines administered, by age

 Janssen vaccine doses administered to date

 Projected supply of COVID-19 vaccines in the US

 Policy options for updated recommendations for use for Janssen COVID-19 vaccine
3

CVST cases reviewed by the Work Group

 6 cases of CVST reported to VAERS

–

–

–

–

–

All 6 among women 18-48 years of age

Interval from vaccine receipt to symptom onset ranged from 6-13 days

 1 case of CVST reported in the Phase 3 clinical trial

25 year old male, no previous medical history, no medications

Day 9 after vaccination: fever, headache

Day 19 after vaccination: seizure, CT with cerebral hemorrhage

Day 21 after vaccination: CVST diagnosed, anti-PF4 positive

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

CVST: Cerebral Venous Sinus Thrombosis 
COVID-19 Cases and Deaths by Sex

https://covid.cdc.gov/covid-data-tracker/#demographics

COVID-19 Cases by Sex, 

January 22, 2020 – April 12, 2021

0 10 20 30 40 50 60 70 80 90 100

Female

Male

Percent

Percent of US population

Percent of cases

COVID-19 Deaths by Sex, 

January 22, 2020 – April 12, 2021

0 10 20 30 40 50 60 70 80 90 100

Female

Male

Percent

Percent of US population

Percent of deaths

*Data from 24,349,551 cases, sex was available for 24,071,425 *Data from 433,171 deaths, sex was available for 432,059

4
COVID-19 Cases by Age Group

https://covid.cdc.gov/covid-data-tracker/#demographics

Data from 24,349,551 cases. Age group was available for 24,176,192

COVID-19 Cases by Age Group, January 22, 2020 – April 12, 2021

0 10 20 30 40 50 60 70 80 90 100

0-4 Years

5-17 Years

18-29 Years

30-39 Years

40-49 Years

50-64 Years

65-74 Years

75-84 Years

85+ Years

Percent

Percent of US population

Percent of cases

5
COVID-19 Associated Hospitalizations by Age Group

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

COVID-19-Associated Hospitalization, by Age Group

Preliminary weekly rates as of April 3, 2021

0

1000

2000

3000

4000

5000

6000

7000

Case Counts

MMWR Week

65+ YR 50-64 YR 18-49 YR 5-17 YR 0-4 YR

6
COVID-19 Deaths by Age Group

https://covid.cdc.gov/covid-data-tracker/#demographics

Data from 433,171 deaths. Sex was available for 433,132

COVID-19 Deaths by Age Group, January 22, 2020 – April 12, 2021

0 10 20 30 40 50 60 70 80 90 100

0-4 Years

5-17 Years

18-29 Years

30-39 Years

40-49 Years

50-64 Years

65-74 Years

75-84 Years

85+ Years

Percent

Percent of US population

Percent of deaths

7
COVID-19 Vaccination Coverage by Age – United States

Data as of April 13, 2021; age available for 92% of doses administered.

https://covid.cdc.gov/covid-data-tracker/#vaccination-demographic 10

≥75 years 78.2%

65-74 years 79.2%

50-64 years 53.2%

40-49 years 40.1%

30-39 years 33.9%

18-29 years 24.4%

Percent Receiving ≥1 dose
Number (in millions) of adults fully, partially, and not 

vaccinated, by age group

Data on vaccine doses as of April 12, 2021; age available for 92% of doses administered.

https://covid.cdc.gov/covid-data-tracker/#vaccination-demographic

https://wonder.cdc.gov Number of persons (in millions)

6 7 8

17 18 13 6 6 7

14

5

3

42

31 26

32

8

6

0

10

20

30

40

50

60

70

18-29 30-39 40-49 50-64 65-74 75+

Fully vaccinated Partially vaccinated Not vaccinated

9
 7,233,726 Janssen doses administered to date

– 1,495,400 Janssen doses administered to females 18-50 years of age*

10

Janssen Doses Administered to Date

Source: 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. 
Janssen Doses Administered to Date by Sex, Age Group, and 

Combined Race and Ethnicity – United States

Sex available for 99% of vaccination records; Age available for 99.9% of vaccination records; Combined race and ethnicity available for 61% of vaccination records

Source: CDC Immunization Data Lake; Includes data reported to CDC as of 4/13/2021 at 6:00 am

Characteristic Doses Administered Percentage

Sex

Male 3,539,227 49.5%

Female 3,400,989 50.5%

Age Group

Under 18 9,299 0.1%

18-49 3,400,989 47.0%

50-64 2,508,374 34.7%

65+ 1,314,359 18.2%

Combined Race and Ethnicity

Hispanic 696,395 15.7%

NH, AI/AN 25,874 0.6%

NH, Asian 206,743 4.7%

NH, Black 429,091 9.7%

NH, Multi/Other 245,033 5.5%

NH, White 2,828,538 63.8%

Total

NH = Non-Hispanic

AI/AN = American Indian / Alaska Native 

11
12

Janssen Doses Administered to Date

Source: 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. 

Thrombocytopenic thrombotic events develop ~6-13 days after vaccine receipt

Prior to March 30: March 30 to April 13

3,466,166 Janssen doses administered

48% of doses

3,767,560 Janssen doses administered

52% of doses

Thrombocytopenic 

thrombotic events postvaccine likely already 

occurred

Thrombocytopenic thrombotic 

events post-vaccine may still 

occur

7,233,726 doses administered in the United States
mRNA vaccines

 Expect ~14 million first doses of Pfizer and Moderna vaccines each week 

Janssen vaccines

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

 Approximately 13 million doses of Janssen vaccines available

–

–

Estimated 3.6M doses available to order

Estimated 9.2M doses currently available at administration sites

 While doses for the Janssen vaccine may be less than mRNA vaccines, Janssen vaccine has 

been used in populations that may be difficult to reach with mRNA vaccines that require 

freezer temperatures or two doses 

13

COVID-19 vaccine Supply Considerations

https://www.whitehouse.gov/briefing-room/statements-releases/2021/04/13/statement-from-jeff-zients-white-house-covid-19-response-coordinator-on-johnson-johnsonvaccine/
 Thrombocytopenic thrombotic events after the AstraZeneca vaccine have occurred 

 In the US, 6 cases of CVST reported after receipt of the Janssen COVID-19 vaccine.

 No cases of CVST with thrombocytopenia reported after receipt of either Pfizer 

and Moderna COVID-19 vaccines

 CVST cases have occurred primarily in younger adults, females

 CVST can be clinically devastating or fatal

 In the US, alternative COVID-19 vaccines (mRNA vaccines) are available

– Based on current projections, supply of both mRNA vaccines fairly stable for near future

14

What is known so far

CVST: Cerebral Venous Sinus Thrombosis 
 True background incidence of CVST with thrombocytopenia

 Specific risk factors for thrombocytopenic thrombotic events 

 Incidence of other thrombotic (non-CVST) cases with thrombocytopenia after 

Janssen vaccine 

 Ability to compare or generalize thrombotic cases after the AstraZeneca 

vaccine to Janssen vaccine

 True incidence of thrombocytopenic thrombotic events/CVST after a 

Janssen/J&J COVID-19 vaccine

– More cases may be identified in the coming days/weeks

15

What we do NOT know 

CVST: Cerebral Venous Sinus Thrombosis 
Policy options: 

Janssen/J&J COVID-19 vaccine
 While overall reported cases are rare, once limited to doses administered to age 

and sex of CVST cases seen, 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 1-2 weeks

 Emphasis that robust safety surveillance is critical

– Signal detection and evaluation of cases occurred as planned 

17

Policy options: Janssen/J&J COVID-19 vaccines

WG Discussion points
18

Policy Options for Janssen Policy Recommendations

Do not recommend use 

of Janssen vaccine

Recommend use of 

Janssen/J&J COVID-19 

vaccine in all adults 

≥18 years of age 
–

–

Adults 50 years of age and older only

Males only

19

Policy Options for Janssen Policy Recommendations

Age or gender

specific populations? 

Do not recommend use 

of Janssen vaccine

Recommend use of 

Janssen/J&J COVID-19 

vaccine in all adults 

≥18 years of age 

Recommend use of 

Janssen/J&J COVID-19 

vaccine in some

populations 
 Sex/gender-based recommendations:

–

–

–

–

Difficult to implement

 Age-based recommendations: 

Concern that we may not have sufficient data at this time to inform specific age cut-off

Acknowledge that many countries in Europe have used age-based approach for the 

AstraZeneca vaccine recommendations 

Allow for additional options (mRNA or Ad-vector) in an older, at-risk population

20

Policy options: Janssen/J&J COVID-19 vaccines

WG Discussion points
 Extending pause while awaiting additional information: 

–

–

Potentially allow for more informed, specific recommendations for the use of the 

Janssen vaccine

• Evaluate risk by age, inform possible age-based recommendation

• Assess if thrombocytopenic thrombosis risk beyond CVST cases 

Could have broad consequences: 

• Individuals may want to receive Janssen vaccine

• Pause could have global implications (pausing clinical trials, availability of Janssen 

vaccine in other countries with more limited supply)

21

Policy options: Janssen/J&J COVID-19 vaccines

WG Discussion points
The Janssen COVID-19 vaccine is recommended for persons 

18 years of age and older in the U.S. population under the FDA’s 

Emergency Use Authorization

22

Previous Janssen vote: 

Questions for ACIP to discuss:

 Does ACIP have enough information to make interim age or riskfactor 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?
For more information, contact CDC

1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.

Thank you