Immunity against the omicron coronavirus variant fades rapidly after a second and third dose of Pfizer and BioNTech’s Covid-19 vaccine, according to peer reviewed research published in JAMA Network Open on Friday, a finding that could support rolling out additional booster shots to vulnerable people as the variant drives an uptick in new cases across the country.
KEY FACTS
Levels of omicron-specific “neutralizing” antibodies—which can target the virus and stop it from replicating—decline rapidly after a second and third dose of Pfizer’s shot, according to the Danish study of 128 people who had received two or three doses.
However, antibody levels started to drop as early as three weeks after the booster shot, falling 4.9-fold for the original variant, 5.6-fold for delta and 5.4-fold for omicron between weeks three and eight.