cdc.gov/coronavirus

COVID-19 vaccine safety update: Primary 

series in young children and booster doses 

in older children and adults

Advisory Committee on Immunization Practices 

(ACIP)

September 1, 2022

Tom Shimabukuro, MD, MPH, MBA

CDC COVID-19 Immunization Safety Unit
Topics

▪ Background on CDC vaccine safety monitoring systems

▪ Safety of primary series mRNA COVID-19 vaccination in 

children ages 6 months–5 years 

▪ Safety of mRNA COVID-19 booster vaccinations in people ages 

5 years and older

▪ Summary

2
+

Vaccine Adverse Event 

Reporting System

http://vaers.hhs.gov

VAERS is the nation’s early warning system for vaccine safety

3
VAERS

Key strengths

▪ Rapidly detects potential 

safety problems 

▪ Can detect rare adverse 

events

Key limitations

▪ Passive surveillance system

▪ Inconsistent quality and 

completeness of information

▪ Reporting biases

▪ Generally, cannot determine 

cause and effect

VAERS accepts reports from everyone (healthcare professionals, patients, 

parents, caregivers, manufacturers, etc.) regardless of the plausibility of 

the vaccine causing the event or the clinical seriousness of the event

4
5

Smartphone-based active safety monitoring

https://vsafe.cdc.gov

Enroll yourself or 

your dependent 

after any dose!
Active safety monitoring for COVID-19 vaccines

V-safe is a voluntary CDC smart phone-based monitoring program 

for COVID-19 vaccine safety in the United States

▪ Uses text messaging and web surveys to check in with vaccine recipients 

after vaccination

▪ Solicits participants’ reports on how they feel after COVID-19 vaccination

• Local injection site reactions (e.g., pain, redness, swelling)

• Systemic reactions (e.g., fatigue, headache, joint pain)

• Health impacts (unable to perform normal daily activities, missed 

school or work, or received care)

▪ Parents can register and complete surveys on behalf of their child

6
Vaccine Safety Datalink (VSD)

7

▪ Established in 1990

▪ Collaborative project between CDC and 9 integrated healthcare organizations 
VSD Rapid Cycle Analysis (RCA)

Aims

▪ To monitor the safety of COVID-19 vaccines weekly using pre-specified 

outcomes of interest among VSD members

▪ To describe the uptake of COVID-19 vaccines over time among eligible VSD 

members overall and in strata by age, site, and race/ethnicity

8
mRNA COVID-19 vaccine safety of primary series 

vaccination in children ages 6 months–5 years

9
U.S. reports to VAERS among children after primary series Pfizer-BioNTech (ages 6 

months–4 years) or Moderna (ages 6 months–5 years) vaccination*(as of August 21, 2022) 

10

* Among children ages 6 months–4 years after Pfizer-BioNTech, and among children ages 6 months–5 years after Moderna, vaccinated during June 18–August 21, 

2022; reports received and processed as of August 23, 2022 

† Dose 1 and dose 2 administered among children described in previous footnote during June 16–August 18, 2022.

‡ 2 reports after Pfizer-BioNTech and 9 reports after Moderna did not have sex reported

§ Based on the Code of Federal Regulations if one of the following is reported: death, life-threatening illness, hospitalization or prolongation of hospitalization, 

permanent disability, congenital anomaly or birth defect

Manufacturer

Doses

admin†

Total

reports

Median 

age

Male‡

n (%)

Female‡

n (%)

Nonserious

n (%)

Serious§

n (%)

Myocarditis 

reports (n)

PfizerBioNTech 890,378 496 3 years 249 (50) 245 (49) 486 (98) 10 (2) 0

Moderna 664,484 521 2 years 272 (52) 240 (46) 512 (98) 9 (2) 0

Total 1,554,862 1,017 3 years 521 (51) 485 (48) 998 (98) 19 (2) 0
Most frequent MedDRA Preferred Terms*

in reports to VAERS following primary series 

Pfizer-BioNTech vaccination in children ages 6 months–4 years†(as of August 21, 2022)

11

Rank MedDRA PT (not mutually exclusive) n (%)

1 Incorrect Dose Administered 87 (18)

2 Pyrexia/fever 84 (17)

3

Product Administered to Patient of 

Inappropriate Age 55 (11)

4 No Adverse Event 54 (11)

5 Rash 52 (11)

6 Product Preparation Issue 50 (10)

7 Vomiting 39 (8)

8 Wrong Product Administered 34 (7)

9 Fatigue 30 (6)

10 SARS-CoV-2 Test Negative 24 (5)

N=496, all reports N=496, clinical outcomes only shown‡

Rank MedDRA PT (not mutually exclusive) n (%)

1 Pyrexia/fever 84 (17)

2 Rash 52 (11)

3 Vomiting 39 (8)

4 Fatigue 30 (6)

5 Urticaria 23 (5)

6 COVID-19 19 (4)

7 Diarrhoea 19 (4)

8 SARS-CoV-2 Test Positive 18 (4)

9 Cough 17 (3)

10 Decreased Appetite 17 (3)

* Medical Dictionary for Regulatory Activities Preferred Terms (https://www.meddra.org/how-to-use/basics/hierarchy) 

† Among children ages 6 months–4 years vaccinated during June 18–August 21, 2022; reports received and processed as of August 23, 2022

‡ Determined by subject matter expert review
Most frequent MedDRA Preferred Terms*

in reports to VAERS following primary 

series Moderna vaccination in children ages 6 months–5 years†(as of August 21, 2022)

12

* Medical Dictionary for Regulatory Activities Preferred Terms (https://www.meddra.org/how-to-use/basics/hierarchy) 

† Among children ages 6 months–5 years vaccinated during June 18–August 21, 2022; reports received and processed as of August 23, 2022 

‡ Determined by subject matter expert review

Rank MedDRA PT (not mutually exclusive) n (%)

1 Pyrexia/Fever 115 (22)

2 Rash 45 (9)

3 Vomiting 45 (9)

4 Urticaria 43 (8)

5 No Adverse Event 42 (8)

6 Expired Product Administered 36 (7)

7 Cough 35 (7)

8 Incorrect Dose Administered 35 (7)

9 SARS-CoV-2 Test Negative 35 (7)

10 Irritability 33 (6)

N=521, all reports N=521, clinical outcomes only shown‡

Rank MedDRA PT (not mutually exclusive) n (%)

1 Pyrexia/Fever 115 (22)

2 Rash 45 (9)

3 Vomiting 45 (9)

4 Urticaria 43 (8)

5 Cough 35 (7)

6 Irritability 33 (6)

7 Fatigue 31 (6)

8 Decreased Appetite 30 (6)

9 Rash Erythematous 28 (5)

10 Diarrhoea 27 (5)
V-safe enrollment among children ages 6 months–≤4 years (PfizerBioNTech) and 6 months–≤5 years (Moderna) 

Data as of August 21, 2022

* Dose 1 and dose 2 administered among children described in previous footnote during June 16–August 18, 2022.

Vaccine and age group

Primary series doses

administered 

nationally*

V-safe 

enrollment

Moderna in children ≤5 years 664,484 14,725 children

Pfizer-BioNTech in children ≤4 years 890,378 8,541 children

13
Reactions and health impacts reported for children aged 6 months–≤2 

years at least once in days 0–7 following COVID-19 vaccination, by dose

Data as of August 21, 2022. Includes 4,749 children (aged 6 months–2 years) who received Pfizer-BioNTech and 8,338 who received Moderna.

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic reaction Any health impact

Percentage

Dose 1 Dose 2

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic

reaction

Any health impact

Percentage

Dose 1 Dose 2

Pfizer-BioNTech

N = 4,749

Moderna

N = 8,338

14
Reactions and health impacts reported for children aged 3–5 years at 

least once in days 0–7 following COVID-19 vaccination, by dose

Data as of August 21, 2022. Includes 3,792 children (aged 3–4 years) who received Pfizer-BioNTech and 6,387 who received Moderna (aged 3–5 years) .

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic reaction Any health impact

Percentage

Dose 1 Dose 2

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic

reaction

Any health impact

Percentage

Dose 1 Dose 2

Pfizer-BioNTech

N = 3,792

Moderna

N = 6,387

15
VSD COVID-19 vaccine RCA prespecified surveillance outcomes

16

Prespecified outcomes Settings

Acute disseminated encephalomyelitis Emergency dept, Inpatient

Acute myocardial infarction – First ever in EHR in ICD-10 era Emergency dept, Inpatient

Acute respiratory distress syndrome Emergency dept, Inpatient

Anaphylaxis – First in 7 days in EHR in ICD-10 era Emergency dept, Inpatient

Appendicitis Emergency dept, Inpatient

Bell’s palsy – First ever in EHR in ICD-10 era Emergency dept, Inpatient, Outpatient

Cerebral venous sinus thrombosis Emergency dept, Inpatient

Disseminated intravascular coagulation Emergency dept, Inpatient

Encephalitis / myelitis / encephalomyelitis Emergency dept, Inpatient

Guillain-Barré syndrome Emergency dept, Inpatient

Immune thrombocytopenia Emergency dept, Inpatient, Outpatient

Kawasaki disease Emergency dept, Inpatient

Multisystem inflammatory syndrome in children/adults (MIS-C/MIS-A) Emergency dept, Inpatient

Myocarditis / pericarditis – First in 60 days in EHR in ICD-10 era Emergency dept, Inpatient

Narcolepsy / cataplexy Emergency dept, Inpatient, Outpatient

Pulmonary embolism – First ever in EHR in ICD-10 era Emergency dept, Inpatient

Seizures (including 0-7 days for youngest ages) Emergency dept, Inpatient

Stroke, hemorrhagic Emergency dept, Inpatient

Stroke, ischemic Emergency dept, Inpatient

Thrombosis with thrombocytopenia syndrome – First ever in EHR in ICD-10 era Emergency dept, Inpatient

Thrombotic thrombocytopenic purpura Emergency dept, Inpatient

Transverse myelitis Emergency dept, Inpatient

Venous thromboembolism – First ever in EHR in ICD-10 era Emergency dept, Inpatient, Outpatient

EHR = Electronic 

health record
VSD RCA results in children ages 6 months–4 years (Pfizer-BioNTech) and 6 

months–5 years (Moderna) for primary series mRNA COVID-19 vaccination

▪ Doses administered:

▪ No statistical signals to date*for any pre-specified surveillance outcomes for 

either mRNA COVID-19 vaccine 

* Data through Aug 13, 2022

Doses PfizerBioNTech Moderna Total

Dose 1 31,784 34,466 66,250

Dose 2 18,729 17,940 36,669

Total 50,513 52,406 102,919

17
Summary: mRNA COVID-19 vaccine safety of primary series vaccination 

in children ages 6 months–5 years

▪ Initial safety findings of both mRNA COVID-19 vaccines (Pfizer-BioNTech and 

Moderna) are consistent with those observed in the clinical trials

▪ Systemic and local reactions are commonly reported adverse events

▪ Vaccination errors are also being reported to VAERS

▪ No unexpected safety findings to date

▪ No evidence of an increased risk for myocarditis following mRNA COVID-19 

vaccination in children ages 6 months–5 years

18
COVID-19 vaccine safety of booster doses in 

people ages 5 years and older

19
U.S. reports to VAERS following 1st and 2nd mRNA COVID-19 

booster vaccinations*(as of August 21, 2022) 

20

* Among persons receiving Pfizer-BioNTech dose 3: children ages 5–11 years vaccinated during May 17–August 21, 2022; children and adolescents ages 12–15 years vaccinated 

during January 3–August 21, 2022, and ages 16–17 years vaccinated during December 9, 2021–August 21, 2022; adults ages ≥18 years vaccinated during September 22, 2021–

August 21, 2022. Among persons receiving Moderna dose 3: adults ages ≥18 years vaccinated during October 20, 2021–August 21, 2022. Among persons ages ≥50 years: dose 4 

Pfizer-BioNTech or Moderna vaccine received during March 29–August 21, 2022.

† Doses of Pfizer-BioNTech dose 3 administered among children ages 5–11 years during June 16–August 18, 2022; children and adolescents ages 12–15 years during January 6–

August 18, 2022; adolescents ages 16–17 years during December 9, 2021–August 18, 2022; adults ages ≥18 years during September 22, 2021–August 18, 2022. Doses of Moderna 

dose 3 administered among adults ages ≥18 years during October 28, 2021–August 18, 2022. Among adults ages ≥50 years, 2nd booster dose of Pfizer-BioNTech or Moderna 

vaccine administered during March 28–August 18, 2022. 

‡ Sex was not reported in approximately 2% of reports.

Booster

dose

Doses

admin†

Total

reports

Median 

age

Male‡

n (%)

Female‡

n (%)

Non-serious

n (%)

Serious

n (%)

1

st booster

(5–11 years)

1,153,611 727 9 years 369 (51) 348 (48) 723 (99) 4 (1)

1

st booster

(≥12 years)

102,063,616 64,265 53 years 21,841 (34) 41,234 (64) 57,048 (89) 7,217 (11)

2

nd booster

(≥50 years)

20,145,400 12,619 68 years 4,556 (36) 7,973 (63) 11,895 (94) 724 (6)
Most frequent MedDRA Preferred Terms*

in reports to VAERS following 1st booster dose 

mRNA COVID-19 vaccinations, ages 5–11 years†(as of August 21, 2022)

21

Rank MedDRA PT (not mutually exclusive) n (%)

1 Product Preparation Issue 197 (27)

2 Incorrect Dose Administered 164 (23)

3 No Adverse Event 139 (19)

4 Product Preparation Error 69 (9)

5

Product Administered To Patient Of 

Inappropriate Age 67 (9)

6 Expired Product Administered 53 (7)

7 Pyrexia/Fever 51 (7)

8 Pain In Extremity 40 (6)

9 Fatigue 37 (5)

10 Vomiting 27 (4)

N=727, all reports N=727, clinical outcomes only shown‡

Rank MedDRA PT (not mutually exclusive) n (%)

1 Pyrexia/Fever 51 (7)

2 Pain In Extremity 40 (6)

3 Fatigue 37 (5)

4 Vomiting 27 (4)

5 Dizziness 24 (3)

6 Headache 23 (3)

7 Injection Site Pain 23 (3)

8 Pain 21 (3)

9 Chills 18 (2)

10 Lymphadenopathy 18 (2)

* Medical Dictionary for Regulatory Activities Preferred Terms (https://www.meddra.org/how-to-use/basics/hierarchy) 

† Among children ages 5–11 years receiving Pfizer-BioNTech dose 3 during May 17–August 21, 2022; reports received and processed as of August 23, 2022

‡ Determined by subject matter expert review
Most frequent MedDRA Preferred Terms*

in reports to VAERS following 1st booster dose 

mRNA COVID-19 vaccinations, ages ≥12 years†(as of August 21, 2022)

22

N=57,048, non-serious reports (clinical outcomes) 

Rank Adverse event (not mutually exclusive) n (%)

1 Headache 7,006 (12)

2 Pyrexia/Fever 6,804 (12)

3 Pain 6,702 (12)

4 Fatigue 6,542 (11)

5 Chills 5,310 (9)

6 COVID-19 4,957 (9)

7 Pain In Extremity 4,272 (7)

8 Nausea 3,548 (6)

9 Dizziness 3,353 (6)

10 Urticaria 3,240 (6)

* Medical Dictionary for Regulatory Activities Preferred Terms (https://www.meddra.org/how-to-use/basics/hierarchy) 

† Among persons receiving Pfizer-BioNTech dose 3: children and adolescents ages 12–15 years vaccinated during January 3–August 21, 2022, and ages 16–17 years vaccinated during 

December 9, 2021–August 21, 2022; adults ages ≥18 years vaccinated during September 22, 2021–August 21, 2022. Among persons receiving Moderna dose 3: adults ages ≥18 years 

vaccinated during October 20, 2021–August 21, 2022. 

N=7,217, serious reports (clinical outcomes)

Rank Adverse event (not mutually exclusive) n (%)

1 COVID-19 2,479 (34)

2 SARS-CoV-2 Test Positive 2,017 (28)

3 Dyspnoea 1,223 (17)

4 Death 794 (11)

5 Asthenia 730 (10)

6 Pyrexia/Fever 651 (9)

7 Fatigue 646 (9)

8 Vaccine Breakthrough Infection 618 (9)

9 Condition Aggravated 615 (9)

10 Chest Pain 578 (8)
Most frequent MedDRA Preferred Terms*

in reports to VAERS following 2nd booster dose 

mRNA COVID-19 vaccinations, ages ≥50 years†(as of August 21, 2022)

23

N=11,895, non-serious reports (clinical outcomes)

Rank Adverse event (not mutually exclusive) n (%)

1 COVID-19 3,951 (33)

2 SARS-CoV-2 Test Positive 2,757 (23)

3 Fatigue 2,057 (17)

4 Cough 1,724 (14)

5 Headache 1,645 (14)

6 Pyrexia/Fever 1,622 (14)

7 Pain 1,247 (10)

8 Oropharyngeal Pain 1,235 (10)

9 Rhinorrhoea 838 (7)

10 Malaise 811 (7)

* Medical Dictionary for Regulatory Activities Preferred Terms (https://www.meddra.org/how-to-use/basics/hierarchy) 

† Among persons receiving Pfizer-BioNTech or Moderna dose 4 during March 29–August 21, 2022

N=724, serious reports (clinical outcomes)

Rank Adverse event (not mutually exclusive) n (%)

1 COVID-19 218 (30)

2 SARS-CoV-2 Test Positive 165 (23)

3 Dyspnoea 91 (13)

4 Asthenia 76 (11)

5 Fatigue 76 (11)

6 Death 66 (9)

7 Vaccine Breakthrough Infection 65 (9)

8 Headache 64 (9)

9 Cough 60 (8)

10 Pyrexia/Fever 60 (8)
VAERS reporting rates of verified myocarditis per 1 million mRNA COVID-19 1st and 

2

nd booster vaccinations (Pfizer-BioNTech or Moderna), days 0–7 post-vaccination*,†

* As of August 18, 2022. Reports verified to meet case definition by provider interview or medical record review.

† An estimated 1–10 cases of myocarditis per 100,000 person years occurs among people in the United States, regardless of vaccination status; adjusted for days 0–7 

risk interval, this estimated background is 0.2 to 2.2 per 1 million person-day 0–7 risk interval (peach shaded cells indicate that reporting rate exceeded estimated 

background incidence for the period) 24

1

st booster (≥5 years) 2nd booster (≥50 years)

Age group Male Female Male Female

5–11 years 0.0 0.0 - -

12–15 years 12.9 0.7 - -

16–17 years 21.6 0.0 - -

18–24 years 13.1 0.6 - -

25–29 years 4.4 2.2 - -

30–39 years 1.9 0.9 - -

40–49 years 0.2 0.6 - -

50–64 years 0.4 0.1 0.0 0.3

65+ years 0.7 0.2 0.0 0.0
VAERS reporting rates of verified myocarditis per 1 million mRNA COVID-19 vaccinations 

(Pfizer-BioNTech and Moderna combined), days 0–7 post-vaccination*,†

* As of August 18, 2022. Reports verified to meet case definition by provider interview or medical record review.

† An estimated 1–10 cases of myocarditis per 100,000 person years occurs among people in the United States, regardless of vaccination status; adjusted for days 0–7 

risk interval, this estimated background is 0.2 to 2.2 per 1 million person-day 0–7 risk interval (peach shaded cells indicate that reporting rate exceeded estimated 

background incidence for the period) 25

Dose 2

(primary series)

1

st booster

dose

Age group Male Female Male Female

5–11 years 2.5 0.7 0.0 0.0

12–15 years 47.1 4.2 12.9 0.7

16–17 years 78.7 7.4 21.6 0.0

18–24 years 39.3 3.9 13.1 0.6

25–29 years 15.3 3.5 4.4 2.2

30–39 years 7.8 1.0 1.9 0.9

40–49 years 3.3 1.6 0.2 0.6

50–64 years 0.7 0.5 0.4 0.1

65+ years 0.3 0.5 0.7 0.2

From 

previous 

slide
Reactions and health impact events reported by v-safe participants aged 5-11 years

at least once in days 0-7 after homologous Pfizer-BioNTech vaccination, by dose

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic reaction Any health impact Unable to perform

daily activities

Unable to work or

attend school

Needed medical care

Percentage

Dose 1 Dose 2 Booster

Includes 3,622 participants who completed at least one survey in the first week after each dose, data collected during May 17–Aug 21, 2022 26
Reactions and health impact events reported by v-safe participants aged 12-17 years

at least once in days 0-7 after homologous Pfizer-BioNTech vaccination, by dose

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic reaction Any health impact Unable to perform

daily activities

Unable to work or

attend school

Needed medical care

Percentage

Dose 1 Dose 2 Booster

Includes 4,369 participants who completed at least one survey in the first week after each dose, data collected during Dec 9, 2021–Aug 21, 2022 27
Reactions and health impact events reported by v-safe participants aged ≥18 years 

at least once in days 0-7 after homologous vaccination, by dose

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic reaction Any health impact

Percentage

Dose 1 Dose 2 Booster

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic

reaction

Any health impact

Percentage

Dose 1 Dose 2 Booster

Pfizer-BioNTech

N = 341,951

Moderna

N = 316,097

Includes participants who completed at least one survey in the first week after each dose, data collected during Sept 22, 2021–Aug 21, 2022 28
Reactions and health impact events reported by v-safe participants aged ≥50 years 

at least once in days 0-7 after homologous vaccination, by dose

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic reaction Any health impact

Percentage

Dose 1 Dose 2 Booster Second Booster

0

10

20

30

40

50

60

70

80

90

100

Any injection site

reaction

Any systemic

reaction

Any health impact

Percentage

Dose 1 Dose 2 Booster Second Booster

Pfizer-BioNTech

N = 128,197

Moderna

N = 131,730

Includes participants who completed at least one survey in the first week after each dose, data collected during Mar 29–Aug 21, 2022 29
VSD COVID-19 vaccine RCA prespecified surveillance outcomes

30

Prespecified outcomes Settings

Acute disseminated encephalomyelitis Emergency dept, Inpatient

Acute myocardial infarction – First ever in EHR in ICD-10 era Emergency dept, Inpatient

Acute respiratory distress syndrome Emergency dept, Inpatient

Anaphylaxis – First in 7 days in EHR in ICD-10 era Emergency dept, Inpatient

Appendicitis Emergency dept, Inpatient

Bell’s palsy – First ever in EHR in ICD-10 era Emergency dept, Inpatient, Outpatient

Cerebral venous sinus thrombosis Emergency dept, Inpatient

Disseminated intravascular coagulation Emergency dept, Inpatient

Encephalitis / myelitis / encephalomyelitis Emergency dept, Inpatient

Guillain-Barré syndrome Emergency dept, Inpatient

Immune thrombocytopenia Emergency dept, Inpatient, Outpatient

Kawasaki disease Emergency dept, Inpatient

Multisystem inflammatory syndrome in children/adults (MIS-C/MIS-A) Emergency dept, Inpatient

Myocarditis / pericarditis – First in 60 days in EHR in ICD-10 era Emergency dept, Inpatient

Narcolepsy / cataplexy Emergency dept, Inpatient, Outpatient

Pulmonary embolism – First ever in EHR in ICD-10 era Emergency dept, Inpatient

Seizures Emergency dept, Inpatient

Stroke, hemorrhagic Emergency dept, Inpatient

Stroke, ischemic Emergency dept, Inpatient

Thrombosis with thrombocytopenia syndrome – First ever in EHR in ICD-10 era Emergency dept, Inpatient

Thrombotic thrombocytopenic purpura Emergency dept, Inpatient

Transverse myelitis Emergency dept, Inpatient

Venous thromboembolism – First ever in EHR in ICD-10 era Emergency dept, Inpatient, Outpatient

EHR = Electronic 

health record
mRNA COVID-19 booster vaccine doses administered in VSD in people 

ages 5–11, 12–17, and ≥18 years, over time*

* Data through Aug 13, 2022 31
VSD RCA results in children ages 5–11 years for 1st mRNA 

COVID-19 booster vaccination*

▪ No statistical signals for any pre-specified surveillance outcomes

32 *Results through Aug 13, 2022
33

Primary series with 

Pfizer-Pfizer OR 

Moderna-Moderna Pfizer-Pfizer Moderna-Moderna

Signal after 1st booster Pfizer OR Moderna Pfizer Moderna

VSD RCA pre-specified outcomes Signal?

Acute disseminated encephalomyelitis No No -*

Acute myocardial infarction No No No

Appendicitis No No No

Bell's palsy No No No

Cerebral venous sinus thrombosis No No No

Disseminated intravascular coagulation No No No

Encephalitis / myelitis / encephalomyelitis No No No

Guillain-Barre syndrome No No No

Stroke, hemorrhagic No No No

Stroke, ischemic No No No

Immune thrombocytopenia No No No

Myocarditis / pericarditis Yes No No

Seizures No No No

Transverse myelitis No No No

Thrombotic thrombocytopenic purpura No No No

Thrombosis with thrombocytopenia syndrome No No No

Venous thromboembolism No No No

Pulmonary embolism No No No

VSD signals for pre-specified outcomes in 21-day risk interval after 1st booster in people 

ages 12 years and older

Results through 

Aug 13, 2022

* Analyses not yet 

possible
Verified myocarditis and pericarditis during the 0–7 risk interval post-vaccination versus the 

comparison interval 22–42 days post-vaccination with 1st booster dose*

Primary series Booster 

vaccine

Cases

in risk 

interval

Cases in 

22–42-day 

comparison 

interval

Adjusted rate ratio

(95% confidence

interval)

2-sided 

p-value

Events/million doses 

(95% confidence

interval)

12–15-year-olds

Males Pfizer – Pfizer Pfizer 4 1 18.50 (1.85 – 551.84) 0.011 61.7 (20.0 – 143.9)**

Females Pfizer – Pfizer Pfizer 0 0 NE (NE) NE 0.0

16–17-year-olds

Males Pfizer - Pfizer Pfizer 8 0 NE (2.03 - ∞) 0.009 189.0 (86.4 – 358.8)**

Females Pfizer - Pfizer Pfizer 2 3 1.10 (0.11 – 9.49) 0.925 36.6 (4.4 – 132.2)

18–39-year-olds

Males

Pfizer - Pfizer

OR

Moderna - Moderna

Pfizer

OR

Moderna

18 7 5.34 (2.11 – 14.74) <0.001 30.9 (18.3 – 48.9)

Males Pfizer - Pfizer Pfizer 10 3 8.15 (2.06 – 41.51) 0.002 31.3 (15.0 – 57.6)

Males Moderna - Moderna Moderna 5 3 3.57 (0.73 – 20.16) 0.116 25.4 (8.3 – 59.3)

Females

Pfizer - Pfizer

OR

Moderna - Moderna

Pfizer

OR

Moderna

4 3 2.68 (0.53 – 14.84) 0.227 4.9 (1.3 – 12.6)

Females Pfizer - Pfizer Pfizer 1 2 0.99 (0.03 – 13.07) 0.969 2.2 (0.1 – 12.3)

Females Moderna - Moderna Moderna 1 1 2.42 (0.06 – 101.49) 0.599 10.7 (2.2 – 31.4)***

*Data through August 20, 2022

** One additional case was in the risk interval but not included because there were no appropriate comparators. These cases are included in the events/million dose calculation.

***Two additional cases were in the risk interval but not included because there were no appropriate comparators. These cases are included in the events/million dose calculation.

34
VSD incidence rates of verified myocarditis/pericarditis in the 0–7 days after 

Pfizer-BioNTech vaccination in people ages 5–39 years, dose 2 and 1st booster*

Dose 2 primary series

Pfizer-BioNTech

1

st booster dose

Pfizer-BioNTech

Cases

Dose 2 

admin

Incidence rate/

million doses (95% CI) Cases

1

st boosters

admin

Incidence rate/

million doses (95% CI)

5-11 years

Males 3 207,958 14.4 (3.0 – 42.2) 0 50,415 0.0 (0.0 – 59.4)

Females 0 202,596 0.0 (0.0 – 14.8) 0 49,261 0.0 (0.0 – 60.8)

12–15 years

Males 31 205,955 150.5 (102.3 – 213.6) 5 81,613 61.3 (19.9 – 143.0)

Females 5 204,074 24.5 (8.0 – 57.2) 0 84,114 0.0 (0.0 – 35.6)

16–17 years

Males 14 102,091 137.1 (75.0 – 230.1) 9 47,874 188.0 (86.0 – 356.9)

Females 1 107,173 9.3 (0.2 – 52.0) 2 55,004 36.4 (4.4 – 131.3)

18–29 years

Males 27 331,889 81.4 (53.6 – 118.4) 7 166,973 41.9 (16.9 – 86.4)

Females 2 400,321 5.0 (0.6 – 18.0) 1 240,226 4.2 (0.1 – 23.2)

30–39 years

Males 5 341,527 14.6 (4.8 – 34.2) 3 197,554 15.2 (3.1 – 44.4)

Females 3 410,713 7.3 (1.5 – 21.3) 1 268,412 3.7 (0.1 – 20.8)

*Primary series surveillance for people ages ≥18 years ended May 21, 2022, all other data through August 20, 2022. 35
VSD incidence rates of verified myocarditis/pericarditis in the 0–7 days after 

Moderna vaccination in people ages 5–39 years, dose 2 and 1st booster*

Dose 2 primary series

Moderna

1

st booster dose

Moderna

Cases

Dose 2 

admin

Incidence rate/

million doses (95% CI) Cases

1

st boosters

admin

Incidence rate/

million doses (95% CI)

5-11 years**

Males N/A N/A N/A N/A N/A N/A

Females N/A N/A N/A N/A N/A N/A

12–15 years**

Males N/A N/A N/A N/A N/A N/A

Females N/A N/A N/A N/A N/A N/A

16–17 years**

Males N/A N/A N/A N/A N/A N/A

Females N/A N/A N/A N/A N/A N/A

18–29 years

Males 19 195,809 97.0 (58.4 – 151.5) 7 109,337 64.0 (25.7 – 131.9)

Females 0 243,560 0.0 (0.0 – 12.3) 1 156,707 6.4 (0.2 – 35.6)

30–39 years

Males 8 216,583 36.9 (15.9 – 72.8) 1 149,468 6.7 (0.2 – 37.3)

Females 1 259,780 3.9 (0.1 – 21.4) 2 191,765 10.4 (1.3 – 37.7)

*Primary series surveillance for people ages ≥18 years ended May 21, 2022, all other data through August 20, 2022.

**Monitoring ongoing, no data provided if less than 2,500 doses given in a subgroup.

36
Summary: mRNA COVID-19 vaccine safety of booster doses in people 

ages 5 years and older

▪ Safety findings are generally consistent with those observed for primary series 

vaccination

▪ Evidence suggests an increased risk for myocarditis following 1st booster dose

• Myocarditis is a rare event following mRNA COVID-19 booster vaccination

‒ CDC has verified 131 myocarditis case reports to VAERS in people ages ≥5 years after 

123,362,627 million mRNA COVID-19 booster vaccinations 

• Risk primarily observed in adolescent and young adult males

• No statistical signal for myocarditis to date in children ages 5–11 years following 1st booster 

▪ In VAERS data, reporting rates of myocarditis are lower following 1st booster 

dose vs. dose 2 of primary series (and lower following dose 1 vs. dose 2 of primary series)

▪ In VSD analyses, myocarditis/pericarditis incidence following 1st booster dose 

and dose 2 of the primary series are similar, though case counts are small and 

confidence intervals around point estimates are wide 37
COVID-19 vaccine safety: pregnancy and reproductive health 

outcomes monitoring

Monitoring systems

• V-safe

• V-safe pregnancy registry 

• VSD

• VAERS

• CISA

38

Outcomes/topics

• Miscarriage

• Stillbirth

• Preterm birth 

• Birth defects

• Pregnancy complications

• Pregnancy outcomes

• Infant outcomes

• Neonatal outcomes

• Maternal adverse events 

and maternal conditions

• Menstrual irregularities

• Post-menopausal bleeding

• Safety of booster doses

• SARS-CoV-2 infection after 

vaccination

• Co-administration with other 

vaccines (e.g., influenza)
▪ To date, for outcomes studied, there have been no concerning findings for 

pregnancy and reproductive health outcomes following COVID-19 vaccination

▪ Data on COVID-19 vaccine safety during pregnancy and reproductive health 

outcomes following vaccination will be presented at a future ACIP meeting 

39

COVID-19 vaccine safety: pregnancy and reproductive health 

outcomes monitoring
Acknowledgments

40

▪ VAERS Team

▪ V-safe Team

▪ Clinical Immunization Safety Assessment 

(CISA) Project

▪ Vaccine Safety Datalink (VSD) Team

▪ CDC Immunization Safety Office

▪ COVID-19 Vaccine Task Force Data 

Monitoring and Reporting Group

▪ FDA/Center for Biologics Evaluation and 

Research

▪ Kaiser Permanente Northern California (VSD)

▪ Marshfield Clinic Research Institute (VSD)

▪ VSD sites

• HealthPartners Institute, Minneapolis, MN

• Kaiser Permanente Colorado, Denver, CO

• Kaiser Permanente Northwest, Portland, OR

• Kaiser Permanente Southern California, Los Angeles, CA

• Kaiser Permanente Washington, Seattle, WA

• Denver Health, Denver, CO
Disclaimer

▪ 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 (CDC) or the U.S. Food and Drug 

Administration (FDA)

▪ Mention of a product or company name is for identification 

purposes only and does not constitute endorsement by CDC or FDA

41
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!