Pfizer and BioNTech announced Wednesday that their coronavirus vaccine appears to provide strong protection against the omicron variant when a booster is received in addition to its initial two doses.
The companies said preliminary studies show three doses of the vaccine neutralize the omicron variant.
“Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it’s clear from these preliminary data that protection is improved with a third dose of our vaccine,” Albert Bourla, chairman and chief executive officer of Pfizer, said.
“Ensuring as many people as possible are fully vaccinated with the first two dose series and a booster remains the best course of action to prevent the spread of COVID-19,” he added.
Those who have only two doses of the vaccine experienced a “more than a 25-fold reduction" in the "neutralization titers” that are produced by vaccines to help fight off a COVID-19 infection, the companies said.
It added that a “vast majority” of vaccine-induced T-cells are not compromised by the more than 30 different mutations in omicron, showing some protection is still given by the first two doses of the vaccine.
The results come after the first study of the omicron variant showed it could partially evade antibody immunity in Pfizer’s vaccine when two doses were given.
A 40-fold reduction in neutralizing antibodies against the new variant was found in the small study compared to previous coronavirus strains when a person had only two doses of the Pfizer vaccine.
Pfizer-BioNTech began working last month on a vaccine specific to the omicron variant, which is still in development.
The results come as the world is rushing to discover vaccines' effectiveness against omicron and determine the variant's transmissibility between individuals.
— Updated at 7:56 a.m.