Breakthroughs that change patients’ lives Confidential 1

Safety & Immunogenicity

Booster (3rd) Dose BNT162b2 (10 μg)

5 to <12 y olds

Study C4591007 

Charu Sabharwal, MD, MPH

Pfizer, Director 

Vaccine Clinical

Research & Development

19 May 2022
Worldwide Research, Development and Medical Confidential 2

Safety and Tolerability

• 401 participants with follow-up from Dose 3 to 1-month post-Dose 3

Immunogenicity

• Subset of 130 participants

• Completed 1MPD3

• Immune responses against SARS-CoV-2 wild type

• Additional 67 participants from Dose 2 evaluable population included for 1MPD2 comparison

• From the 130 participants above, 30 participants immune responses against the 

Omicron variant

Booster Dose: 5 to <12 years Phase 2/3 BNT162b2 10 μg

Safety and Immunogenicity Assessments 

Data as Agreed Upon with the FDA
Worldwide Research, Development and Medical Confidential 3

Study Design and Timelines: 

5 to <12 Years of Age

BNT162b2 10 mcg

Dose

2 Dose 3 1MPD3 6MPD3 12MPD3

7 DAY 

Reactogenicity

Dose

1

7 DAY 

Reacto

21 

days

7 DAY 

Reacto

6MPD2

7 Jun 21

Phase 2/3

2 Dose 

Series

Initiated

31 Jan 22

3rd Dose 

Existing 

Participants

Initiated

Data Cut-off

22 Mar 22

4 Jan 22

Protocol 

Amended

3rd Dose

29 Oct 21

EUA

Immunobridging 

criteria met 

90.7% 

efficacy 

Delta

1MPD2

10 Sep 21

Enrollment 

complete

~4,500

• EUA= Emergency Use Authorization
Worldwide Research, Development and Medical Confidential 4

Demography for 5 to <12 -year olds Who Received Dose 3 of BNT162b2

Overall, representative of C4591007 participants BNT162b2 (10μg)

(N=401) n (%)

Sex

Male 210 (52.4)

Female 191 (47.6)

Race

White 281 (70.1)

Black or African American 29 (7.2)

American Indian or Alaska native 8 (2.0)

Asian 31 (7.7)

Multiracial 46 (11.5)

Ethnicity Hispanic/Latino 92 (22.9)

Non-Hispanic/non-Latino 306 (76.3)

Age at vaccination (Dose 1) Mean (SD) 7.9 (1.75)

Min, Max (5, 11)

Obese Yes 39 (9.7)

Comorbiditiesa Yes 119 (29.7)

History of COVID-19 Yes 0 (0%)

Baseline (Dose 1) positive for 

SARS CoV-2 Yes 22 (5.5%)

a. Participants who had at least one of the prespecified comorbidities based on MMWR 69(32);1081-

1088 and/or obesity (BMI ≥ 95th percentile
Worldwide Research, Development and Medical Confidential 5

3rd Dose Vaccine Administration Timing Mostly Occurred 8-9 months after 

Dose 2: 5 to <12 Years of Age Safety population

BNT162b2 (10μg)

N=401

n (%)

Vaccinated Dose 3 401 (100.0)

Dose 3 

(Time from Dose 2)

≥5 to <6 Months 1 (0.2)

≥6 to <7 Months 1 (0.2)

≥7 to <8 Months 51 (12.7)

≥8 to <9 Months 348 (86.8)

Data cutoff date 22Mar2022
Worldwide Research, Development and Medical Confidential 6

Dose 3 Mean Follow-up Time of 1.3 Months 

5 to <12 Years of Age Safety population (Unblinded)

BNT162b2 (10μg)

N=401

n (%)

Time from Dose 3 to 

cutoff date

<1 Month 0

≥1 to <2 Months 401 (100.0)

Mean 1.3 (0.17)

Median 1.3

Min, Max (1.0, 1.8)

Data cutoff date 22Mar2022
Breakthroughs that change patients’ lives Confidential 7

Safety 
Worldwide Research, Development and Medical Confidential 8

Local Reactions 7 Days After Each Dose 

Mostly Mild to Moderate

Mild Moderate Severe Grade 4

Redness Swelling Pain at Injection Site

11.6%

16.5% 15.6%

9.5%

14.0% 16.4%

77.6%

72.2% 73.9%

0%

20%

40%

60%

80%

100%

Dose 1 Dose 2 Dose 3 Dose 1 Dose 2 Dose 3 Dose 1 Dose 2 Dose 3

Redness and swelling severity definition: Mild: ≥0.5 to 2.0 cm; moderate: >2.0 to 7.0 cm; severe: >7.0 cm Grade 4= necrosis

Pain at injection site severity definition: Mild=no interference; Moderate=some interference; Severe=prevents daily activity; Grade 4=ER visit or hospitalization 

Dose 1: N=398; Dose 2: N=399; Dose 3: N=371

Severe reactions at Dose 3: 

• Pain at the injection site: 2 participants – onset within 1-2 days of vax resolved with 2 days of which 1 participant also reported severe headache – no other symptoms. 

• Redness – 1 participant with moderate redness Day 2 and became severe on Day 4. Duration 12 days. 

n=2; [0.5%]

n=1; [0.3%]
Worldwide Research, Development and Medical Confidential 9

Systemic Events Within 7 Days After Each Dose 

Mostly Mild to Moderate

Systemic events: Mild Moderate Severe Grade 4

Fever: 38.0 °C-38.4 °C 38.4 °C-38.9 °C 38.9 °C-40.0 °C >40.0 °C

Fever Fatigue Headache Chills Vomiting Diarrhea Muscle

Pain

Joint

Pain

3.5%

8.8% 6.7%

37.4%

46.6% 45.6%

23.6%

30.1% 34.0%

6.0%

10.3% 10.5%

2.0% 1.8% 2.4%

6.8% 6.5% 4.9% 8.0%

12.5%

18.3%

3.8% 5.5% 6.7%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd

Fatigue, headache, chills, muscle pain, joint pain severity definition: Mild=no interference; Moderate=some interference; Severe=prevents daily activity; Grade 4=ER visit or hospitalization

Vomiting severity definition: Mild=1-2 time in 24h; Moderate=>2times in 24h; Severe=Requires IV hydration; Grade 4=ER visit or hospitalization

Diarrhea severity definition: Mild=2-3 times in 24h; Moderate=4-5 times in 24h; Severe=6 or more times in 24h; Grade 4=ER visit or hospitalization 

Dose 1: N=398; Dose 2: N=399; Dose 3: N=371

n=7 

[1.9%]

n=3 

[0.8%]

n=1 

[0.3%] n=1 

[0.3%]

n=3 

[0.8%]
Worldwide Research, Development and Medical Confidential 10

Overall Dose 3 to Cut-off (22Mar2022) Adverse Events Were 

Consistent with the 2 Dose Series 5 to <12 year olds

Any AE Related AE Any SAE Related SAE Withdrawal 

due to AE

Death

0

20

40

60

80

100

9.0 4.7 0 0 0 0

Proportion of subjects (%)

Reporting at least 1 AE

BNT162b2 10μg Post Dose 3 (N=401)
Worldwide Research, Development and Medical Confidential 11

Adverse Events (≥1.0%) Consistent with Reactogenicity Events and other Events 

Typical for This Age Group: System Organ Class for 5 to <12 year olds From Dose 3 to 1 

Month After Dose 3 - Safety Population

1. Predominantly reflect local reactions at the injection site and systemic reactions of fatigue

2. Predominantly reflects systemic events of diarrhoea and vomiting

3. Predominantly reflects systemic events of headache

9.0

2.2

2.0

1.5

1.5

1.0

1.0

0 20 40 60 80 100

BNT162b2 10 μg (N=401)

Percent of Subjects Reporting ≥1 AE

Any adverse events

Infections and infestations

Blood and Lymphatic system 

disorders

Gastrointestinal disorders2

General disorders and 

administration site conditions1

Nervous system disorders3

Respiratory, thoracic and

mediastinal disorders
Breakthroughs that change patients’ lives Confidential 12

Adverse Events of 

Clinical Interest 

and other important terms
Worldwide Research, Development and Medical Confidential 13

• None of the following were reported in BNT162b2 recipients up to the data cutoff

point:

• Anaphylaxis

• Myocarditis/pericarditis

• Bell’s palsy (or facial paralysis/paresis)

• Appendicitis 

• Rash - 1 event 

• Mild facial rash

• Considered unrelated to vaccine by the investigator  wearing a face mask

• Onset was 11 days post dose 3 and resolved 4 days later

Few AEs of clinical interest corresponding to those requested by 

FDA or CDC list of AESIs
Worldwide Research, Development and Medical Confidential 14

• Post Dose 3, 10 (2.4%) BNT162b2 participants

• Post Dose 2  0.9%

• Post Dose 3 adults (30μg)  5.2%

• Overall, mild and considered to be related by investigator

• Occurred primarily in axillary or cervical nodes

• Onset within 2 days of booster vaccination

• Reported as resolved within ~1 week after onset

Lymphadenopathy observed in 5 to <12 year old age group, but Lower 

Frequency Compared to Adults with 3rd Dose of BNT162b2 30 ug 
Worldwide Research, Development and Medical Confidential 15

• Safety data from 401 subjects who received a booster (3rd) dose of 

BNT162b2 10 μg did not identify any new safety concerns 

• Reactogenicity was mostly mild to moderate and short lived after third 

dose and generally comparable to that observed after the second 

dose

• AESIs were limited to one case of rash

Overall Safety Conclusions
Breakthroughs that change patients’ lives Confidential 16

Immunogenicity
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Descriptive Immunogenicity Analysis: 1MPD3 compared to 1MPD2

5 to <12 Years of Age

COVID Illness Visits continue 

Dose 3 1MPD3 6MPD3 12MPD3

7 DAY 

Reactogenicity

Dose

1

Dose

2

7 DAY 

Reactogenicity

21 

days

7 DAY 

Reactogenicity

1MPD2 6MPD2

3-Dose Immunogenicity Set • 123 participants completed 1MPD3 by 15 Mar 2022 who 

with/without evidence of infection. 

• 30: part of 1MPD2 immuno-bridging subset.

• Evaluable Without evidence of infection

• Of 123  67

• Of 30  29 (contributed to the Omicron analysis)

2-Dose Set

Additional 67 without 

evidence of infection 

randomly selected 

1MPD2 evaluable 

population 

Dose 2 and Dose 3 evaluable sets -- Received all doses of vaccine at 

the same dose level as randomized (ie, two or three doses) and did 

not have important deviations to study procedure
Worldwide Research, Development and Medical Confidential 18

BNT162b2 10 μg 2-Dose and 3-Dose Sets elicited robust neutralization titers 

against SARS-CoV-2 wild type in participants without evidence of prior 

infection: 5 to <12 Years of Age – Evaluable Immunogenicity Population

GMT and GMRs were similar to participants with and without prior evidence of infection

Before Dose 1 1M PD2 Before Dose 3 1M PD3

1

10

100

1000

10000

20.5

1253.9

271.0

2720.9

NT50 (titer) GMT

264

264

146 96 67 67

NT50, 50% neutralizing titer; Wild type, USA-WA-1/2020

146 3-Dose Set: 79 

2-Dose Set: 67 3-Dose Set: 29 

2-Dose Set: 67 3-Dose Set: 67 3-Dose Set: 67

GMR 2.17 (1.76, 2.68)

1MPD3/Dose 3 GMFR

Without evidence of infection  10.0

With and without evidence of infection  6.2
Worldwide Research, Development and Medical Confidential 19

High Seroresponse Rate (98.5%) against SARS-CoV-2 wild type After 

Dose 3 in participants without evidence of prior infection: 5 to <12 Years of 

Age – Evaluable Immunogenicity Population

BNT162b2 (10μg)

3 Dose Set 2 Dose Set Total

Assay

Dosing/

Sampling Time 

Point N n

%

(95% CI) N n

%

(95% CI) N n

%

(95% CI)

SARS-CoV-2 

neutralization 

assay - NT50

(titer)

2/1 Month 29 29 100

(88.1, 100.0) 67 67 100.0(94.6, 100.0) 96 96 100.0(94.6, 100.0)

3/Prevax 67 52 77.6

(65.8, 86.9) 67 52 77.6(65.8, 86.9)

3/1 Month 67 66 98.5

(92.0, 100.0) 67 66 98.5(92.0, 100.0)

• 3-Dose immunogenicity set included the first 123 participants received Dose 3 and completed 1 month post–Dose 3 visit prior to March 15, 2022. 

Among those, 30 had blood sample collection at 1 month post–Dose 2.

• 2-Dose immunogenicity set included extra 67 participants randomly selected from previous Dose-2 evaluable immunogenicity population and without 

evidence of infection up to 1-month post–Dose 2 subset used for 2-dose immunobridging analysis

• Seroresponse defined as a ≥4 fold rise from baseline. If baseline < LLOQ, then postvaccination result ≥4 x LLOX is considered a seroresponse
Worldwide Research, Development and Medical Confidential 20

Booster (3rd) dose of BNT162b2 10 μg Elicited Neutralizing Titers 

Against a SARS-CoV-2 Omicron in Participants Without Evidence of 

Prior Infection 

5 to <12 Years of Age – Evaluable Immunogenicity Population

FFRNT = Fluorescent focus reduction neutralization test

BNT162b2 (10μg)

Assay

Dosing/

Sampling 

Time Point N

GMT 

(95% CI) GMR

SARS-CoV-2 FFRNT strain 

B.1.1.529 (Omicron) - NT50

(titer)

2/1 Month 29 27.6

(22.1, 34.5) 22

3/1 Month 17 614.4

(410.7, 919.2)

SARS-CoV-2 FFRNT reference 

strain - NT50 (titer)

2/1 Month 29 323.8

(267.5, 392.1) 5

3/1 Month 17 1702.8

(1282.6, 2260.7)
Worldwide Research, Development and Medical Confidential 21

Booster (3rd) dose of BNT162b2 10 μg Elicited Neutralizing Titers 

Against a SARS-CoV-2 Omicron in Participants With and Without 

Evidence of Prior Infection 

5 to <12 Years of Age – Evaluable Immunogenicity Population

FFRNT = Fluorescent focus reduction neutralization test

BNT162b2 (10μg)

Assay

Dosing/

Sampling 

Time Point N

GMT 

(95% CI) GMR

SARS-CoV-2 FFRNT strain 

B.1.1.529 (Omicron) - NT50

(titer)

2/1 Month 30 27.3

(22.0, 33.9) 36

3/1 Month 30 992.7

(675.9, 1458.1)

SARS-CoV-2 FFRNT reference 

strain - NT50 (titer)

2/1 Month 30 335.1

(275.1, 408.3) 6

3/1 Month 30 2152.7

(1714.9, 2702.2)
Worldwide Research, Development and Medical Confidential 22

• In participants with and without evidence of prior infection, 

administration of a booster (3rd) dose of BNT162b2 10 μg elicited 

robust neutralization titers against SARS-CoV-2 wild type

• A booster (3rd) dose of BNT162b2 10μg elicited neutralizing titers

against SARS-CoV-2 Omicron in participants with and without 

evidence of prior infection

• Overall the immune response associated with a booster (3rd) dose of 

BNT162b2 10μg given at least 6 months after the second dose is 

expected to confer protection against COVID-19, including that due to 

Omicron

Immunogenicity Conclusions
Breakthroughs that change patients’ lives Confidential 23

Questions