South African coronavirus variant may ‘escape antibodies, cause reinfection’

On December 18, 2019, South Africa announced the detection of a new coronavirus variant which was spreading rapidly. This particular variant is much more infectious than the original virus.

By: Satata Karmakar | | Updated: January 23, 2021 8:58 am

South Africa's coronavirus variant poses 're-infection risk': study

Raising questions over the possibility of reinfection by the coronavirus strain which was detected in South Africa, researchers have come up with a study report. The authors of the study stated that this variant of the Covid-19 virus has the ability to escape neutralisation by antibodies from recovered COVID-19 patients. Also Read - COVID-19 vaccine at ₹250 too low to sustain, Companies ‘feel betrayed’: Kiran Mazumdar Shaw

What Is This New Variant?

On December 18, 2019, South Africa announced the detection of a new coronavirus variant which was spreading rapidly. According to the experts, this particular variant is much more contagious and infectious than the original virus and can easily transmit from person-to-person. This Covid-9 virus variant is also known as 501.V2. Also Read - Gurugram apartment declared containment zone after 20 tested positive for COVID-19

How Does This New Variant Infect Human Cells?

The novel lineage of the coronavirus — 501Y.V2 — has mutations in nine parts of its spike protein, which enables it to infect human cells. Also Read - With 33 positive cases, 3 more COVID-19 clusters identified in Bengaluru

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.

The Variant Can Escape The Antibodies

The authors of the study stated that – 501Y.V2 shows “substantial or complete escape from neutralizing 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 neutralizing 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 spike-based vaccines.”

What Helps This Strain To Escape The Antibodies? Are You At Risk?

Commenting on the study, clinical virologist Julian Tang from the University of Leicester in the UK, said this variant can 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 notes considerable binding to the 501Y.V2 virus by other non-neutralising antibodies, which the virologist believes can still offer some significant protection against this variant.

“The study also acknowledges that it cannot assess the impact of this virus variant on T-cell responses so some additional defense 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.

“Previously Infected Patients Are Susceptible To Re-Infection”

Calling the findings are “potentially concerning,” the researchers said these are laboratory findings, adding that “it would be unwise to extrapolate to clinical effects in humans at this stage.”

Talking about the possibility of re-infection, they said – “The study does, however, raise the possibility that immunity gained from past COVID-19 infection may be lower for re-infection with the South African variant.

“This study suggests that previously infected individuals may be susceptible to reinfection with virus variants,” researchers further added.

The findings also have implications for the effectiveness of current COVID-19 vaccines based on the spike protein of the original virus.

Speaking to the media, the authors said that it is important for everyone right now to determine the neutralising ability of the antibodies against virus variants generated in response to vaccination and study the immune response in individuals infected with the same.

Published : January 22, 2021 9:42 am | Updated:January 23, 2021 8:58 am

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