January 21, 2021

expert reaction to preprint reporting that SARS-CoV-2 501Y.V2 variant (first detected in South Africa) escapes neutralisation by convalescent plasma

A preprint, an unpublished non-peer reviewed study, looks at the escape of the South African variant of SARS-CoV-2, 501Y.V2, from neutralization by convalescent plasma.

Prof Eleanor Riley, Professor of Immunology and Infectious Disease, University of Edinburgh, said:

“This study adds to an emerging body of evidence that some SARS-CoV-2 variants can escape neutralisation by antibodies induced by prior infection. Whilst worrying, this is not particularly surprising.

“We are watching – in real time – an animal virus evolve and adapt to a new host (us). Because of the very large number of infections around the world, this evolution is happening very, very quickly and will likely lead to the emergence of a new, highly human-adapted variant that eventually becomes the dominant circulating virus. The bad news is that this new, human-adapted virus is likely to be much more infectious than the original virus; the good news is that it doesn’t (so far, at least) seem to be more dangerous. What we don’t yet know – and only time will tell – is whether this human-adapted virus will became a stable, relatively invariant, fifth endemic human coronavirus or whether it will continue to mutate in a less predictable manner (like influenza virus).

“It seems very likely that we will, at some point, need to tweak the vaccine so that it better represents the dominant human-adapted variant. In the meantime, we need to monitor the situation. It is  quite possible that the existing vaccines will continue to protect against the new variants as the human immune response to the vaccine is highly diverse and not wholly dependent upon neutralising antibodies.”

Dr Simon Clarke, Associate Professor in Cellular Microbiology, said:

“While not yet peer reviewed by independent scientists, this is a very interesting and timely study, using a relatively small set of samples.  It sets out to answer the question of whether antibodies generated in response to COVID-19 will be effective against the new variant which was first observed in South Africa.  Despite the small study size, the data clearly indicate that antibodies that are effective against the older coronavirus variants are much less effective against the newer, fast-spreading variant of concern.

”While studies such as this are important, they do not take into account any effect which the mutation may have on T cell immunity, which is an important part of vaccine induced immunity.  Further studies will be needed to get the full picture.”

Prof Lawrence Young, Virologist and Professor of Molecular Oncology, Warwick Medical School, said:

“This is more evidence that a variant of the virus is able to partially evade immune protection. This preprint confirms that the South African variant of SARS-CoV-2 is able to escape the virus blocking antibody responses induced by prior natural infection. It differs from other studies by using convalescent plasma from individuals confirmed to have been previously infected with an original SARS-CoV-2 that didn’t contain the mutations of the spike gene that are found in the South African virus variant. The study uses live authentic viruses to show that the South African variant has a dramatically reduced ability to be neutralised by convalescent plasma from 6 donors. The convalescent plasma was taken approximately 1 month after the onset of symptoms and the neuralisation effect on the virus variant varied from complete to partial knockout. While only examining antibodies from 6 donors, the study presents strong data in support of the ability of the South African variant to evade recognition by antibodies induced by prior infection with an earlier virus variant. It once again highlights the possibility that individuals previously infected with one virus variant may be susceptible to re-infection with a different virus variant. It also raises concerns about the effectiveness of current SARS-CoV-2 vaccines which are all based on the spike gene from the original Wuhan virus.  It is important that we now determine the degree to which neutralising antibodies generated in response to current vaccines are capable of blocking infection with the South African and other (e.g. Brazilian) virus variants. We also need to urgently study the immune response in individuals infected with these virus variants to determine whether they induce protective immunity.”

https://www.krisp.org.za/publications.php?pubid=316

All our previous output on this subject can be seen at this weblink:

www.sciencemediacentre.org/tag/covid-19

Declared interests

Prof Eleanor Riley: “No conflicts of interest.”