The largest real-world study of a COVID-19 vaccine to date shows that Pfizer/BioNTech's shot is safe and linked to substantially fewer adverse events than SARS-CoV-2 infection in unvaccinated patients.A team led by researchers from the Clalit Research Institute in Tel Aviv, Israel, and Harvard University matched vaccinated Israelis 16 years and older (median age, 38) with similar but unvaccinated people infected with SARS-CoV-2 from Dec 20, 2020, to May 24, 2021.
They then derived risk ratios (RRs) and risk differences 42 days after vaccination (short- to medium-term) using the Kaplan-Meier estimator.The analysis of the Pfizer vaccine, which the US Food and Drug Administration fully approved earlier this week, involved 1.7 million