N Dagan et al. NEJM 2021;384:1412-23. DOI: 10.1056/NEJMoa2101765. PDF: BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Mass Vaccination Setting

Each study group (vaccinated and unvaccinated) included 596,618 persons. Key finding:

• Estimated effectiveness in preventing death from Covid-19 was 72% (95% CI, 19 to 100) for days 14 through 20 after the first dose.