Pfizer-BioNTech COVID-19 mRNA Vaccine Study Overview
Updated: Jan 2
Pfizer-BioNTech vaccine phase II/III study overview
- 43,448 participants enrolled
- 37,586 participants analyzed for consideration of FDA EUA in Nov 2020
Median follow-up 2 months
Notable Inclusion Criteria:
- Participants ≥ 16 years old
- Participants ≥ 12 years old in later analyses
- Comorbidities in 46.3% of study participants incl obesity (35.1%), diabetes (7.8%) and chronic pulmonary disease (7.8)
- Others include history of HTN, MI, PVD, liver disease, CHF, HBV, HCV and HIV/AIDS
Notable Exclusion Criteria:
- Pregnancy prior or during study period
- Primary Endpoints
(1) Vaccine efficacy after 7 days post Dose 2 in participants without prior evidence of SARS-CoV-2 infection: 95.0%
- 8 COVID-19 cases in vaccinated vs 162 COVID-19 cases in unvaccinated participants
- Similar efficacy across age groups, genders, racial and ethnic groups and participants with medical comorbidities
(2) Vaccine efficacy after 7 days post Dose 2 in participants with or without prior evidence of SARS-CoV-2 infection: 94.6%
- Secondary Endpoints
(1) Prevention of severe COVID-19 following second dose
- 1 severe COVID-19 case in vaccinated vs 3 severe COVID-19 in unvaccinated participants
(2) Prevention of severe COVID-19 following first dose
- Vaccine efficacy: 88.9%
(3) Prevention of COVID-19 following first dose with or without prior evidence of SARS-CoV-2 infection
- Vaccine efficacy: 82.0%
For reference, vaccine efficacy of 50% or greater was considered a successful vaccine at the beginning of development
Cumulative incidence of COVID-19 diverges at ~ Day 14
- Vaccine efficacy for prevention of COVID-19 after first dose 1: 82%.
- But, no data on protection > 21 days after first dose
- Efficacy dose not appear to wane within 2 month study period
- Mild to moderate flu-like symptoms 1-2 days after infection representing increased local and systemic immune system activity.
- Most common solicited adverse reactions were injection site reactions (84.1%), fatigue (62.9%), headache (55.1%), muscle pain (38.3%), chills (31.9%), joint pain (23.6%), fever (14.2%).
- Higher incidence after second dose
- Higher incidence in younger study participants
- Proportions of participants who reported at least 1 SAE were 0.6% in the vaccine group and 0.5% in the placebo group.
- Most common SAEs appendicitis (0.04%), acute myocardial infarction (0.02%), cerebrovascular accident (0.02%), pneumonia (0.03%), atrial fibrillation (0.02%), and syncope (0.02%).
- Bell’s palsy reported in greater numbers in the vaccine group but at a rate similar to general population
1. FDA Briefing Document, Pfizer-BioNTech COVID-19 Vaccine, 10 Dec 2020