Third dose of Pfizer increases antibodies against omicron

A new study evaluating the efficacy of the vaccine for COVID-19 of Pfizer/BioNTech against the omicron variant indicates that three doses could offer “a sufficient level of protection” against the disease.

The omicron (B.1.1.529) of SARS-CoV-2 that circulates throughout the world is highly transmissible because it has accumulated a very high number, higher than other times, of mutations, especially in the spike protein, which the virus used to enter the human cell and the common target, with different technologies, of current vaccines.

This implies that recognition by neutralizing antibodies is compromised.

In a study published in the journal Science, researchers from both pharmaceutical companies led by Alexander Muik analyzed the Wuhan pseudovirus (original) and the beta, delta and omicron variants in sera from 51 participants who received two or three doses of the vaccine. COVID-19 based on messenger RNA.

After two doses, the sera had neutralizing titers more than 22-fold reduced against omicron compared to the original Wuhan virus.

One month after the third dose of the preparation, neutralization titers against omicron were multiplied by 23 compared to those of the two doses, with titers similar to those of neutralization against the coronavirus Wuhan primeval after two doses.

Data suggest that a third dose of this vaccine increases antibody-based immunity against omicron, consistent with previous observations that the third vaccination amplifies humoral immune responses against variants of concern, the authors write.

“More real-world and clinical trial data will soon emerge to address the efficacy of a third dose against omicron-mediated COVID-19.”, they conclude.