(Reuters) – Antibodies induced by the Moderna Inc and Pfizer Inc/BioNTech vaccines are dramatically less effective at neutralizing some of the most worrying coronavirus variants, a new study suggests.

Researchers obtained blood samples from 99 individuals who had received one or two doses of either vaccine and tested their vaccine-induced antibodies against virus replicas engineered to mimic 10 globally circulating variants.

Five of the 10 variants were “highly resistant to neutralization,” even when volunteers had received both doses of the vaccines, the researchers reported in Cell. All five highly resistant variants had mutations in the spike on the virus surface – known as K417N/T, E484K, and N501Y – that characterize a variant rampant in South Africa and two variants spreading rapidly in Brazil.

In keeping with previous studies, the proportion of neutralizing antibodies dropped 5- to 6-fold against the variants discovered in Brazil. Against the variant discovered in South Africa, neutralization fell 20- to 44-fold.

A variant circulating now in New York has the E484K mutation. “While studies of the New York variant are ongoing, our findings suggest that similar variants harboring E484K may be harder for vaccine-induced antibodies to neutralize,” study leader Alejandro Balazs of Harvard University and the Massachusetts General Hospital told Reuters.

“Despite our results,” he added, “it’s important to consider that vaccines raise other kinds of immune responses which could protect against developing severe disease.”

SOURCE: https://bit.ly/3bWB1Ko Cell, online March 12, 2021.

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