Pfizer/BioNTech COVID-19 Vaccine Neutralizes Brazil Variant in Lab Study

By Michael Erman

March 09, 2021

NEW YORK (Reuters) - The COVID-19 vaccine from Pfizer Inc and BioNTech SE was able to neutralize a new variant of the coronavirus spreading rapidly in Brazil, according to a laboratory study published in the New England Journal of Medicine on Monday.

Blood taken from people who had been given the vaccine neutralized an engineered version of the virus that contained the same mutations carried on the spike portion of the highly contagious P.1 variant first identified in Brazil, the study conducted by scientists from the companies and the University of Texas Medical Branch found.

The scientists said that compared to neutralization of a previous less contagious version of the virus from last year (USA-WA1/2020), the vaccine-induced response against the P1 virus and the UK variant virus known as B.1.1.7 were "roughly equivalent."

Geometric mean titers (GMT) of neutralizing antibodies against the USA-WA1/2020 virus, the spike of the UK B.1.1.7 variant, and the P1 variant were 532, 633, and 437, respectively.

In contrast, GMT against three engineered versions of the South African B.1.3.5 variant were 195, 485, and 331, respectively.

The spike, used by the virus to enter human cells, is the primary target of many COVID-19 vaccines.

In previously published studies, Pfizer had found that its vaccine neutralized other more contagious variants first identified in the United Kingdom and South Africa, although the South African variant may reduce the proportion of antibodies elicited by the vaccine that are protective.

Pfizer has said it believes its current vaccine is highly likely to still protect against the South African variant. However, the drugmaker is planning to test a third booster dose of their vaccine as well as a version retooled specifically to combat the variant in order to better understand the immune response.

SOURCE: https://bit.ly/3kYSoNy The New England Journal of Medicine, online March 8, 2021.

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