Pfizer Jab Provides Less Immunity To Omicron Than Other Variants: Study

Researchers at the Africa Health Research Institute in Durban, South Africa, found omicron resulted in about a 40-fold reduction in levels of neutralizing antibodies produced by people who had received two doses of the Pfizer-BioNTech SE shot.

Pfizer Inc.'s vaccine provides less immunity to the omicron variant than to other major versions of Covid-19, according to laboratory experiments that still indicated a third dose may help stop the highly mutated strain.

Researchers at the Africa Health Research Institute in Durban, South Africa, found omicron resulted in about a 40-fold reduction in levels of neutralizing antibodies produced by people who had received two doses of the Pfizer-BioNTech SE shot, compared with the strain detected in China almost two years ago.

The loss of immune protection is "robust, but not complete," Alex Sigal, head of research at the laboratory, said in an online presentation of the first reported experiments gauging the effectiveness of the vaccine against the new variant.

"There will be more breakthrough" of vaccine-induced immunity, Sigal said. "A good booster probably would decrease your chance of infection, especially severe infection leading to more severe disease. People who haven't had a booster should get one, and people who have been previously infected should be vaccinated."