The vaccine was 100% effective in preventing disease in a study in South Africa, where a mutated strain of Corona virus (B1351) is spreading, despite the relatively small number of participants reaching 800.
Although the new efficacy rate, 91.3 percent, is less than the 95 percent reported in the 44,000 study conducted in November, several mutated strains of the coronavirus have spread around the world since then.
Albert Burla, CEO of Pfizer, said the new findings, which include data from more than 12,000 who were fully vaccinated at least six months ago, pave the way for a request for approval from U.S. regulators.
The U.S. Food and Drug Administration has approved the vaccine for emergency use.
Biontech CEO Ugur Shaheen said the research data “provide the first clinical results showing that the vaccine can effectively protect against currently circulating mutated strains, a critical factor in achieving herd immunity and eradicating this pandemic.”
Experts fear that new strains moving in South Africa and Brazil may be resistant to existing vaccines.