Clinical Trials – Vaccine Efficacy
Page last reviewed 21 April 2023
Key Points
Key Points are meant to be a scientific, factual summary of the available information that relates to the Pfizer-BioNTech COVID-19 Vaccine as supported by referenced publications within this section. Conclusions should not be drawn from the inclusion or absence of information.
BNT162b2 CLINICAL TRIALS AND VACCINE EFFICACY
- Vaccine Efficacy of monovalent BNT162b2 was studied in the following clinical trials:
- A Phase 1/2/3 randomized, placebo-controlled, observer-blinded pivotal trial in participants ≥ 12 years old,(1-3)including a sub-analysis in patients with a history of cancer.(4)
- A Phase 2/3 randomized, placebo-controlled, observer-blinded trial in children 5 to 11 years old.(5)
- A Phase 3 ongoing randomized, placebo-controlled trial in participants ≥ 16 years old who received a booster dose.(6)
- Vaccine Efficacy results from peer-reviewed publications of clinical trial results are presented in the Tables below:
- The vaccine efficacy reported was as observed in the clinical trials. Vaccine efficacy is expected to naturally wane over time and may also be impacted by the emergence of new variants.
- Vaccine Efficacy results from Clinical Trials for BNT162b2 Primary Vaccination, VE % (95% CI):
| Vaccine Efficacy Outcome for 2 doses | Polack et al a,1 N = 40,137 |
Thomas et al, NEJM b,2 N = 44,486 |
Thomas et al, Vaccines c,4 N = 3,813 |
Frenck et al d,3 N = 2,260 |
Walter et ale,5 N = 2,268 |
|---|---|---|---|---|---|
| Population | ≥ 16 years | ≥ 12 years | ≥ 12 years with history of cancer |
12-15 years | 5-11 years |
| Endpoint time period | ≥ 7 days after 2nd dose | Up to 6 months after 2nd dose | Up to 6 months after 2nd dose | ≥ 7 days after 2nd dose | ≥ 7 days after 2nd dose |
| Data Cutoff | Oct 9, 2020 | Mar 13, 2021 | Mar 13, 2021 | Mar 13, 2021 | Sep 6, 2021 |
| VE% (95% CI) against COVID-19 in patients without prior infection |
95.0 (90.3-97.6) | 91.3 (89.0-93.2) | 94.4 (85.1-98.5) | 100 (75.3-100) | 90.7 (67.7-98.3) |
| VE% (95% CI) against COVID-19 in patients with & without prior infection |
94.6 (89.9-97.3) | 91.1 (88.8-93.0) | 94.4 (85.2-98.5) | 100 (78.1-100) | 90.7 (67.4-98.3) |
| VE% (95% CI) against severe - COVID-19 |
Not reported in this study |
96.7 (80.3-99.9) | Not reported in this study |
h | i |
- Vaccine Efficacy results from Clinical Trials for monovalent BNT162b2 Booster, VE % (95% CI):
| Booster Efficacy Outcome for 3rd dose |
Moreira et al f,g,6 N = 10,125 |
|---|---|
| Population | ≥ 16 years |
| Endpoint time period | ≥ 7 days after 3rd dose |
| Data Cutoff | Oct 5, 2021 |
| VE% (95% CI) against COVID-19 in patients without prior infection |
95.3 (89.5-98.3) |
| VE% (95% CI) against COVID-19 in patients with & without prior infection |
94.6 (88.5-97.9) |
| VE% (95% CI) against severe - COVID-19 |
j |
Footnotes:
a This original publication reported vaccine efficacy data for 36,523 participants 16 years of age and older without baseline infection: 40,137 participants with and without prior infection using data through October 9, 2020. Median follow-up was 2 months.1
b This follow-up publication including up to 6 months follow-up reported vaccine efficacy data for 44,165 randomized participants 16 years of age and older and 2,264 randomized 12 to 15 years of age, including 42,094 participants without baseline infection; 44,486 participants with and without prior infection using data through March 13, 2021. During combined blinded and open-label periods, 55% of the participants in the BNT162b2 group had 6 months of follow-up or more after the second dose.2
c This sub-analysis publication including up to 6 months follow-up in patients with a history of cancer reported vaccine efficacy data for 3,813 total participants with a history of past or active neoplasm (malignancy or benign/unknown tumor) using data through March 13, 2021.4
d This publication and EUA Fact sheet reported vaccine efficacy data for 2,260 total participants 12 to 15 years of age, including 1,983 without baseline infection; 2,229 participants with and without prior infection using data through March 13, 2021. Overall, 1,308 participants (58%) had at least 2 months of follow-up after the second dose.3
e This publication and EUA Fact sheet reported vaccine efficacy data for 2,268 total participants 5 to 11 years of age, including 1,305 without prior infection using data through September 6, 2021. Median follow-up was 2.3 months.5
f Relative Vaccine Efficacy was estimated as 100 × (1‒IRR), where IRR is the calculated ratio of confirmed COVID-19 illness per 1000 person-years of follow-up in the BNT162b2 dose 3 group to the corresponding illness rate in the placebo dose 3 group. Both groups had received two doses of the BNT162b2 vaccine in the pivotal trial.
g This publication reported relative vaccine efficacy for 10,125 total participants 16 years of age and older, including 4,695 without prior infection; 4,993 participants with and without prior infection using data through October 5, 2021. Median follow-up was 2.5 months.6
h No cases of severe COVID-19 were observed in the Frenck et al study.3
i No cases of severe COVID-19 were observed in the Walter et al study.5
j No cases of severe COVID-19 were observed in BNT162b2 recipients in the Moreira et al study.6
