Pfizer Inc and BioNTech said on Thursday their vaccine is around 91% effective at preventing COVID-19, citing updated trial data that included participants inoculated for up to six months.
The shot also showed early signs of preventing disease in a small subset of study volunteers in South Africa, where a concerning new variant called B.1.351 is circulating.
Although lower than the stunning 95% efficacy result reported from its 44,000-person clinical trial in November, overall efficacy of 91.3% shows the vaccine to be a powerful tool against an evolving virus. The virus now has more transmissible forms and those that have been shown to evade antibody protection in lab studies and real-world clinical trials.
“These data reinforce our view that we have some really potent vaccines,” said Danny Altmann, a professor of immunology at Britain’s Imperial College London, who was not involved in the Pfizer trial.
Pfizer’s Chief Executive Officer Albert Bourla said the updated result, which includes data on more than 12,000 people fully inoculated for at least six months, positions the drugmakers to submit for full U.S. regulatory approval.