Real-World Study of Pfizer, Moderna Vaccines Confirms High Effectiveness

The Pfizer/BioNTech and Moderna vaccines are highly effective at preventing SARS-CoV-2 infections among healthcare and essential workers, a real-world study by the Centers for Disease Control and Prevention (CDC) has confirmed.

The study evaluated the effectiveness of the two messenger-RNA vaccines at preventing symptomatic infection among 3,950 individuals across six states during 13 weeks from mid-December to mid-March.

The results showed that, two weeks after receiving a single dose, the risk of infection was cut by 80 percent, and following administration of a second dose, the risk of infection plummeted by 90 percent after two or more weeks.

The findings of effectiveness are in line with previous phase 3 data evaluating the mRNA vaccines for efficacy against COVID-19 disease. But besides being based on real-world data, the study also evaluated the vaccines’ effectiveness against infections that did not result in symptoms, the CDC said. ― Jason Scott