There’s growing speculation that the South African variant of SARS-CoV-2 might partially evade antibodies, indicating that people have very little protection from reinfection if they’ve previously caught COVID-19.
The whole question of COVID-19 reinfections, when a person comes infected with the disease a second time, is not deeply understood, although it’s thought that most people have some protection from reinfection as their immune system has developed neutralizing antibodies to the virus. Recent research from the UK indicates that past infection provides 83 percent protection for five months.
However, this might not necessarily be true with the South African variant, known as 501Y.V2.
The National Institute For Communicable Diseases Of South Africa collected COVID-19 convalescent plasma, antibody-rich plasma of someone who has recovered from the infection, from 44 people. When exposed to the South African variant, just under half did not respond with neutralizing antibodies. The research, which has not yet been peer-reviewed, can be read on the preprint server bioRxiv.
“The blood samples from half the people we tested showed that all neutralizing activity was lost. This suggests that they may no longer be protected from re-infection. In the other half, the levels of antibodies were reduced and so the risk of re-infection is not known,” the National Institute For Communicable Diseases Of South Africa said in a statement.
This is thought the South African variant escapes neutralization from antibodies as it features specific mutations on the viruses’ spike protein, which the antibodies bind to.
Explaining the findings, Professor Lawrence Young, Virologist and Professor of Molecular Oncology at Warwick Medical School, said: “It is a very thorough study that examines the impact of specific mutations in the spike gene of 501Y.V2 and how these affect the binding of neutralising antibodies.”
“Similarities between the mutations in 501Y.V2 spike and the variant recently found in Brazil suggest that this Brazilian variant will also exhibit significant levels of neutralisation resistance. This study suggests that previously infected individuals may be susceptible to reinfection with virus variants – something which has already been reported in two cases in Brazil,” Young added.
Professor Young is referring to recent reports from Brazil in which people who had previously been infected with COVID-19 appear to have been reinfected with the South African variant, just as this new research suggests might happen.
The South African COVID-19 ministerial advisory committee also announced this week that the new variant spreading is likely to be more contagious than other strains. Unfortunately, it’s still unclear whether the South African COVID-19 strain will still effectively respond to the vaccines, but scientists are closely investigating this.
"This may be a virus that can escape some of the immune effects of antibodies," but "we don’t know to what degree," Sir Patrick Vallance, the UK’s chief scientific adviser, told Sky News on Wednesday.
"We should get information on clinical effects because vaccinations are occurring in South Africa, they are occurring in Brazil, and they are occurring in other places variants may occur, so we should get some more information on that. They are more worrying in the sense they are a little more different in terms of how the immune system may recognize them," Sir Vallance explained.
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