Vaccine Information: Pfizer-BioNTech Covid-19 Vaccine (Page 5 of 8)


18.1 Efficacy of Primary Series in Participants 16 Years of Age and Older

Study 2 is a multicenter, multinational, Phase 1/2/3, randomized, placebo-controlled, observer-blind, dose-finding, vaccine candidate-selection, and efficacy study in participants 12 years of age and older. Randomization was stratified by age: 12 through 15 years of age, 16 through 55 years of age, or 56 years of age and older, with a minimum of 40% of participants in the ≥56-year stratum. The study excluded participants who were immunocompromised and those who had previous clinical or microbiological diagnosis of COVID-19. Participants with preexisting stable disease, defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 6 weeks before enrollment, were included as were participants with known stable infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV).

In the Phase 2/3 portion of Study 2, based on data accrued through November 14, 2020, approximately 44,000 participants 12 years of age and older were randomized equally and received 2 doses of Pfizer-BioNTech COVID-19 Vaccine (30 mcg modRNA) or placebo separated by 21 days. Participants are planned to be followed for up to 24 months, for assessments of safety and efficacy against COVID-19.

The population for the analysis of the primary efficacy endpoint included, 36,621 participants 12 years of age and older (18,242 in the Pfizer-BioNTech COVID-19 Vaccine group and 18,379 in the placebo group) who did not have evidence of prior infection with SARS-CoV-2 through 7 days after the second dose. Table 7 presents the specific demographic characteristics in the studied population.

Table 7: Demographics (population for the primary efficacy endpoint)*
All eligible randomized participants who receive all vaccination(s) as randomized within the predefined window, have no other important protocol deviations as determined by the clinician, and have no evidence of SARS-CoV-2 infection prior to 7 days after Dose 2.
Pfizer-BioNTech COVID-19 Vaccine (30 mcg modRNA).
100 participants 12 through 15 years of age with limited follow-up in the randomized population received at least 1 dose (49 in the vaccine group and 51 in the placebo group). Some of these participants were included in the efficacy evaluation depending on the population analyzed. They contributed to exposure information but with no confirmed COVID-19 cases, and did not affect efficacy conclusions.
Includes multiracial and not reported.
Number of participants who have 1 or more comorbidities that increase the risk of severe COVID-19 disease • Chronic lung disease (e.g., emphysema and chronic bronchitis, idiopathic pulmonary fibrosis, and cystic fibrosis) or moderate to severe asthma • Significant cardiac disease (e.g., heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension) • Obesity (body mass index ≥30 kg/m2) • Diabetes (Type 1, Type 2 or gestational) • Liver disease

Pfizer-BioNTech COVID-19 Vaccine (N=18,242) n (%)

Placebo (N=18,379) n (%)



9318 (51.1)

9225 (50.2)


8924 (48.9)

9154 (49.8)

Age (years)

Mean (SD)

50.6 (15.70)

50.4 (15.81)




Min, max

(12, 89)

(12, 91)

Age group

≥12 through 15 years

46 (0.3)

42 (0.2)

≥16 through 17 years

66 (0.4)

68 (0.4)

≥16 through 64 years

14,216 (77.9)

14,299 (77.8)

≥65 through 74 years

3176 (17.4)

3226 (17.6)

≥75 years

804 (4.4)

812 (4.4)



15,110 (82.8)

15,301 (83.3)

Black or African American

1617 (8.9)

1617 (8.8)

American Indian or Alaska Native

118 (0.6)

106 (0.6)


815 (4.5)

810 (4.4)

Native Hawaiian or other Pacific Islander

48 (0.3)

29 (0.2)

Other §

534 (2.9)

516 (2.8)


Hispanic or Latino

4886 (26.8)

4857 (26.4)

Not Hispanic or Latino

13,253 (72.7)

13,412 (73.0)

Not reported

103 (0.6)

110 (0.6)



8432 (46.2)

8450 (46.0)


9810 (53.8)

9929 (54.0)

Human Immunodeficiency Virus (HIV) infection (not included in the efficacy evaluation)

The population in the primary efficacy analysis included all participants 12 years of age and older who had been enrolled from July 27, 2020, and followed for the development of COVID-19 through November 14, 2020. Participants 18 through 55 years of age and 56 years of age and older began enrollment from July 27, 2020, 16 through 17 years of age began enrollment from September 16, 2020, and 12 through 15 years of age began enrollment from October 15, 2020.

The vaccine efficacy information is presented in Table 8.

Table 8: Vaccine Efficacy – First COVID-19 Occurrence From 7 Days After Dose 2, by Age Subgroup – Participants Without Evidence of Infection and Participants With or Without Evidence of Infection Prior to 7 Days After Dose 2 – Evaluable Efficacy (7 Days) Population
Note: Confirmed cases were determined by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and at least 1 symptom consistent with COVID-19 (symptoms included: fever; new or increased cough; new or increased shortness of breath; chills; new or increased muscle pain; new loss of taste or smell; sore throat; diarrhea; vomiting).
Participants who had no evidence of past SARS-CoV-2 infection (i.e., N-binding antibody [serum] negative at Visit 1 and SARS-CoV-2 not detected by NAAT [nasal swab] at Visits 1 and 2), and had negative NAAT (nasal swab) at any unscheduled visit prior to 7 days after Dose 2 were included in the analysis.
Pfizer-BioNTech COVID-19 Vaccine (30 mcg modRNA).
N = Number of participants in the specified group.
n1 = Number of participants meeting the endpoint definition.
Total surveillance time in 1000 person-years for the given endpoint across all participants within each group at risk for the endpoint. Time period for COVID-19 case accrual is from 7 days after Dose 2 to the end of the surveillance period.
n2 = Number of participants at risk for the endpoint.
No confirmed cases were identified in adolescents 12 through 15 years of age.
Credible interval for vaccine efficacy (VE) was calculated using a beta-binomial model with a beta (0.700102, 1) prior for θ=r(1-VE)/(1+r(1-VE)), where r is the ratio of surveillance time in the active vaccine group over that in the placebo group.
Confidence interval (CI) for vaccine efficacy is derived based on the Clopper and Pearson method adjusted to the surveillance time.

First COVID-19 occurrence from 7 days after Dose 2 in participants without evidence of prior SARS-CoV-2 infection *


Pfizer-BioNTech COVID-19 Vaccine N =18,198 Cases n1 § Surveillance Time (n2 # )

Placebo N =18,325 Cases n1 § Surveillance Time (n2 # )

Vaccine Efficacy % (95% CI)

All subjects Þ

82.214 (17,411)

1622.222 (17,511)

95.0 (90.3, 97.6)ß

16 through 64 years

71.706 (13,549)

1431.710 (13,618)

95.1 (89.6, 98.1)à

65 years and older

10.508 (3848)

190.511 (3880)

94.7 (66.7, 99.9)à

First COVID-19 occurrence from 7 days after Dose 2 in participants with or without evidence of prior SARS-CoV-2 infection


Pfizer-BioNTech COVID-19 Vaccine N =19,965 Cases n1 § Surveillance Time (n2 # )

Placebo N =20,172 Cases n1 § Surveillance Time (n2 # )

Vaccine Efficacy % (95% CI)

All subjects Þ

92.332 (18,559)

1692.345 (18,708)

94.6 (89.9, 97.3)ß

16 through 64 years

81.802 (14,501)

1501.814 (14,627)

94.6 (89.1, 97.7)à

65 years and older

10.530 (4044)

190.532 (4067)

94.7 (66.8, 99.9)à provides trustworthy package insert and label information about marketed drugs and vaccines as submitted by manufacturers to the U.S. Food and Drug Administration. Package information is not reviewed or updated separately by Every individual vaccine label and package insert entry contains a unique identifier which can be used to secure further details directly from the U.S. National Institutes of Health and/or the FDA.

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