Pfizer-BioNTech COVID-19 Vaccine Highly Effective 6 Months After Second Dose

Vaccine efficacy was observed to be 91.3%, measured 7 days through up to 6 months after the second dose.

Topline data from a phase 3 study evaluating the Pfizer-BioNTech COVID-19 vaccine showed that it was highly effective up to 6 months after the second dose.

According to the updated analysis, vaccine efficacy was observed to be 91.3% (95% CI, 89.0-93.2), measured 7 days through up to 6 months after the second dose. In total, there were 927 confirmed symptomatic cases of COVID-19 in the trial of 46,307 participants; 850 cases occurred in the placebo group and 77 cases occurred in the BNT162b2 group.

The analysis also showed that the vaccine was 100% effective at preventing severe COVID-19 disease, as defined by the Centers for Disease Control and Prevention and 95.3% effective against severe COVID-19 disease as defined by the Food and Drug Administration (FDA).

Moreover, the vaccine was observed to be 100% effective in preventing COVID-19 cases in South Africa, where the B.1.351 lineage is prevalent (9 cases were reported in the placebo group among 800 enrolled participants). In an exploratory analysis, 6 of the 9 strains were confirmed to be of the B.1.351 variant.

The safety profile of BNT162b2 was consistent with previously reported results. There were no serious safety concerns reported in participants up to 6 months after the second dose.

“These data confirm the favorable efficacy and safety profile of our vaccine and position us to submit a Biologics License Application to the US FDA,” said Albert Bourla, Chairman and CEO, Pfizer. “The high vaccine efficacy observed through up to 6 months following a second dose and against the variant prevalent in South Africa provides further confidence in our vaccine’s overall effectiveness.”


Pfizer and BioNTech confirm high efficacy and no serious safety concerns through up to six months following second dose in updated topline analysis of landmark COVID-19 vaccine study. [press release]. New York, NY and Mainz, Germany: Pfizer Inc. and BioNTech SE; April 1, 2021. 

This article originally appeared on MPR