Brazil, South African Covid variants less susceptible to antibodies: Study

Variant forms of the novel coronavirus which were first reported in South Africa and Brazil are less efficiently inhibited by antibodies from recovered patients and vaccinated individuals, a new study confirms.

According to the research, published in the journal Cell, recovery from COVID-19 as well as vaccination may offer only incomplete protection against these mutant virus forms.

"This is worrisome because the rapid spread of variants that might not be efficiently inhibited by antibodies could undermine our current vaccination strategy," said Stefan Pohlmann, a co-author of the study from the German Primate Center in Gottingen.

These virus variants have mutations in the spike protein -- the structure on the surface of the virus that is responsible for attachment to host cells -- the researchers said.

In order for the virus to enter a cell, they said it must first attach to the host cell surface using its spike protein, which is located on the viral envelope.

The spike protein is also the target for antibody therapies and vaccines aimed at preventing the virus from replicating in the body, they researchers added.

Based on the research, the scientists said an antibody used for COVID-19 therapy did not inhibit the South African and Brazilian coronavirus variants -- B.1.351 and P.1.

"Moreover, these variants were less well inhibited by antibodies from convalescent or vaccinated individuals, they partially bypassed the neutralising effect of the antibodies," said Jan Munch, another co-author of the study.

The study noted that vaccination or recovery from COVID-19 may offer reduced protection from SARS-CoV-2 variants B.1.351 and P.1.

"Our findings show that it is important to limit the spread of the virus as much as possible until widespread vaccination is feasible. Otherwise, we risk the emergence of new variants that cannot be effectively controlled by the currently available vaccines," said Markus Hoffmann, first author of the study.