Pfizer Vaccine
This post is meant to be a growing post, with the different sources of information on the efficacy of the Pfizer vaccine.
CDC
The first is from a study in 2020 December, cited by the CDC claiming in a clinical trial of 43,000 people, the efficiacy was 95% (90.3%-97.6% for 95% CI). Importantly, the median age was 52 years old. There were low
The body of evidence for the Pfizer-BioNTech COVID-19 vaccine was primarily informed by one large, randomized, double-blind, placebo-controlled Phase II/III clinical trial that enrolled >43,000 participants (median age = 52 years, range = 16–91 years) (5,6). Interim findings from this clinical trial, using data from participants with a median of 2 months of follow-up, indicate that the Pfizer-BioNTech COVID-19 vaccine was 95.0% effective (95% confidence interval = 90.3%–97.6%) in preventing symptomatic laboratory-confirmed COVID-19 in persons without evidence of previous SARS-CoV-2 infection. Consistent high efficacy (≥92%) was observed across age, sex, race, and ethnicity categories and among persons with underlying medical conditions. Efficacy was similarly high in a secondary analysis including participants both with or without evidence of previous SARS-CoV-2 infection
V-Safe
The vaccine rollout is tracked with the v-safe app, where patients can report any adverse effects. The report from 16FEB-2021, and I’ve copied the full report from the FDA to my site here. The report has a huge caveat, that only 4M of 55M people taking a vaccine used the tool (7% rate). My suspicion is that, this population that reported the adverse affects is over-represented, but it would be hard to confirm or deny this hypothesis. Given the data we have, only 1.6M of the 4M users reported any issues:
- 70-80% reported injection site pain
- Second done reporting of fatigue, chills, and fever were higher than day 1 reporting by percentage; however, again, it is hard to quantify the selection bias. Given low initial participation rate, retention in the survey was likely limited to people who had problems.