Pfizer and BioNTech say vaccine is 91% effective at 6 months, protects against variants
Pfizer and BioNTech said their COVID-19 vaccine remains 91.3% effective up to 6 months after administration of the second dose, according to an updated analysis of a phase 3 study.
The study, which evaluated vaccine safety in more than 44,000 participants aged 16 years or older, also found that the vaccine was 100% effective in preventing severe disease under the CDC’s definition and 95.3% effective against severe disease under the FDA’s definition.
Additionally, the vaccine was found to be 100% effective in preventing COVID-19 in South Africa, where the B.1.351 variant is common, the companies said.
“It is an important step to further confirm the strong efficacy and good safety data we have seen so far, especially in a longer term follow-up,” Ugur Sahin, MD, PhD, CEO and co-founder of BioNTech, said in a press release. “These data also provide the first clinical results that a vaccine can effectively protect against currently circulating variants, a critical factor to reach herd immunity and end this pandemic for the global population.”
Among 927 symptomatic COVID-19 cases that occurred in the trial, 850 were in the placebo group and 77 in the vaccinated group (91.3% vaccine efficacy [VE]; 95% CI, 89-93.2). Among 800 participants in South Africa, all nine cases of COVID-19 occurred in the placebo group (100% VE; 95% CI, 53.5-100).
Under the CDC’s definition, 32 cases of severe illness were observed in the placebo group and none in the vaccinated group (100% VE; 95% CI, 88-100). Under the FDA’s definition, 21 severe cases were identified in the placebo group and one in the vaccinated group (95.3% VE; 95% CI, 71-99.9).
No major safety concerns occurred in trial participants, and side effects were consistent with those previously reported.
“These data confirm the favorable efficacy and safety profile of our vaccine and position us to submit a Biologics License Application to the U.S. FDA,” Pfizer Chairman and CEO Albert Bourla, DVM, PhD, said in the release. “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 announced this week that the vaccine, which has been authorized since December in the United States for use in people aged 16 years or older, is also protective in adolescents aged 12 to 15 years. The companies plan to submit that data to the FDA, and experts said it means a vaccine could be available for this age group by next school year.