Promising reports on vaccine efficacy

The messenger RNA vaccines from Pfizer-BioNTech and Moderna were 90 percent effective at preventing COVID-19 infections in real-world settings, according to the Centers for Disease Control and Prevention (CDC) Morbidity and Mortality Weekly Report published March 29. Researchers evaluated the efficacy of the vaccines among 3,950 health-care personnel, first responders and other essential workers who did not have a previous confirmed COVID-19 case. The majority of participants in the study were fully vaccinated, having received both vaccine doses, and 477 received a single dose.

In a separate report released today by Pfizer and BioNTech, the companies announced that the ongoing Phase 3 clinical trial of its vaccine confirms its protection lasts at least six months after the second dose, and appears to be fully effective against the B.1.351 variant.