Omicron variant and vaccine protection: Pfizer third dose and antibodies, study

Antibodies to the Omicron variant of the coronavirus remain at a high level 4 months after the booster dose of Pfizer / Biontech’s anticovid vaccine. These are the first indications of the study carried out by researchers from the University of Texas Medical Branch, Pfizer and BioNTech. Scientists analyzed samples from vaccinated subjects and focused on the presence and action of antibodies against older strains of the virus and against a laboratory-treated version of the Omicron variant. The study, which has not yet been reviewed, has shown that two doses of Pfizer vaccine cannot neutralize Omicron.

“Three doses increase the intensity and breadth” of the blocking action against the variant, say Pei-Yong Shi and Xuping Xie, co-authors of the study. Further clinical and laboratory data will provide more in-depth guidance on “duration of protection, potential need for a new supplemental dose at a later date” and will clarify “whether a modified vaccine for Omicron is required”.

According to the research, antibody levels decrease slightly in the weeks following the administration of the booster dose but are still present 4 months after the injection. The data do not indicate that the 4-month deadline is the maximum target and further studies are needed to outline the picture also in the period following the first quarter. Pfizer and Biontech also reiterated that two doses of the vaccine – without the use of the booster – could guarantee protection against the severe form of the disease.