Sunday, January 24, 2021

Virus Strain Discovered in South Africa Poses ‘Re-infection Risk’: Says Study


Jan 21, 2021 06:58 PM

The coronavirus variant detected in South Africa poses a "significant re-infection risk" and raises concerns over vaccine effectiveness, according to preliminary research on Wednesday, as separate studies suggested the strain discovered in Britain would likely be constrained by immunizations. 

Several new variants - each with a cluster of genetic mutations - have emerged in recent weeks, sparking fears over an increase in infectiousness as well as suggestions that the virus could begin to elude immune response, whether from prior infection or a vaccine.

These new variants, detected from Britain, South Africa and Brazil, have mutations to the virus' spike protein, which enables the virus to latch onto human cells and therefore plays a key role in driving infections.

But it is one mutation in particular - known as E484K and present in the variants detected in South Africa and Brazil, but not the one from Britain - that has experts particularly worried about immunity "escape."

In a new study, which has not yet been peer reviewed, researchers in South Africa tested the variant found there - called 501Y.V2 - against blood plasma from recovered COVID-19 patients. 

They found that it was resistant to neutralizing antibodies built up from prior infection, but said more research was needed into the effectiveness of ­other parts of the immune response.

"Here we show that the 501Y.V2 ­lineage, which contains nine spike ­mutations and rapidly emerged in South Africa during the second half of 2020, is largely resistant to neutralizing ­antibodies elicited by infection with ­previously circulating lineages," the ­authors said.

"This suggests that, despite the many people who have already been infected with SARS-CoV-2 globally and are presumed to have accumulated some level of immunity, new variants such as 501Y.V2 pose a significant re-infection risk."

The researchers added that this might also affect the use of convalescent plasma as a treatment for COVID-19. 

They also suggested it could have "implications" for vaccines developed based on immune responses to the virus's spike protein.

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