BioNTech and Pfizer are the first manufacturers of a COVID vaccine to issue an official update on the efficacy of their shot against Omicron.
The German and U.S. companies said two doses of their vaccine resulted in significantly lower neutralizing antibodies but a third dose boosted those antibodies by a factor of 25.
"We believe that T-cell responses induced by vaccination, particularly increased by the third dose, will still be active also against the Omicron variant," said BioNTech CEO Uğur Şahin during a press conference.
The Omicron variant, first detected in southern Africa last month, has triggered global alarm about another surge in infections. Cases have already been reported from Japan to the United States and across Europe.
The World Health Organization classified Omicron on Nov. 26 as a "variant of concern" but said there was no evidence to support the need for new vaccines specifically designed to tackle the variant and its mutations.
Nevertheless, the companies said they would continue efforts to bring an Omicron-specific COVID-19 vaccine to market.