South African coronavirus variant may escape antibodies, cause reinfection, say scientists

Scientists believe the findings underscore the prospect of reinfection with such distinct variants

of the virus carrying these mutations, and ‘may foreshadow reduced efficacy of current spikebased

vaccines’

South African coronavirus variant may escape antibodies, cause reinfection, say scientists

A lineage of the novel coronavirus, first reported to have emerged in South Africa, escapes

neutralisation by antibodies from recovered COVID-19 patients, says a new study which raises

questions on the possibility of reinfection by this strain.

According to the yet-to-be peer reviewed study, published in the preprint platform bioRxiv, the

novel lineage of the coronavirus—501Y.V2—has mutations in nine parts of its spike protein,

which enables it to infect human cells.

In the research, the scientists, including those from the University of the Witwatersrand in

South Africa, tested the neutralisation activity of plasma from patients who recovered from

prior infection with other strains of the coronavirus against the 501Y.V2 variant.

They found that nearly half—21 of 44—of the samples had no detectable neutralising activity

against this variant.

According to the scientists, 501Y.V2 shows “substantial or complete escape from neutralising

antibodies in COVID-19 convalescent plasma”.

“Here we show that the 501Y.V2 lineage, that contains nine spike mutations, and rapidly

emerged in South Africa during the second half of 2020, is largely resistant to neutralising

antibodies elicited by infection with previously circulating lineages,” the researchers wrote in

the study.

They believe the findings underscore the prospect of reinfection with such distinct variants of

the virus carrying these mutations, and “may foreshadow reduced efficacy of current spikebased

vaccines”.

Commenting on the study, clinical virologist Julian Tang from the University of Leicester in

the UK, said this variant could escape neutralising antibody responses largely due to the

presence of two mutations in the spike (S) region — one in the 484th amino acid position and

the other in the 417th molecule of the protein.

“This may reduce some efficacy from S-protein-based vaccine-induced antibodies in some

people,” Tang said.

However, he added that the study also noted considerable binding to the 501Y.V2 virus by

other non-neutralising antibodies, which the virologist believes could still offer some

significant protection against this variant.

“The study also acknowledges that it could not assess the impact of this virus variant on T-cell

responses so some additional defence will arise from this, as well as other naturally existing

innate components of the immune system in those infected in addition to any residual vaccine

protection,” Tang said.

“Further real life studies will be needed to assess the true impact of this South African 501Y.V2

variant on the vaccinated South African population outside of a laboratory context and in the

presence of other natural human immune responses,” he added.

Calling the findings “potentially concerning”, Liam Smeeth, Professor of Clinical

Epidemiology at the London School of Hygiene and Tropical Medicine, however, said these

were laboratory findings, adding that “it would be unwise to extrapolate to clinical effects in

humans at this stage”.

Smeeth said the study did, however, raise the possibility that immunity gained from past

COVID-19 infection may be lower for re-infection with the South African variant.

Lawrence Young, virologist and professor of molecular oncology, Warwick Medical School,

concurred.

https://www.tribuneindia.com/news/health/south-african-coronavirus-variant-may-escapeantibodies-

cause-reinfection-say-scientists-201675