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South African and Brazilian variants ‘may allow virus to bypass natural immune response’
Some of the mutations seen in variants of the coronavirus from Brazil and South Africa appear to allow the virus to bypass some of people’s immune responses, a leading virologist said.
Professor Wendy Barclay, who advises the Government’s response to Covid-19, said that as natural immunity becomes more dense in certain parts of the world, some variants have a “fitness advantage” and are therefore more likely to spread.
He explained that the mutations themselves are not increasingly of concern, but are a little less controlled by previous immune responses, so they will be the most suitable variants.
Professor Barclay, director of G2P-UK and director of the department of infectious diseases and director of influenza virology at Imperial College London, said: “It is not that the mutations themselves are becoming more of a concern.
“It is likely that the viruses that have some mutations, which means that they are a little less controlled by our previous immune responses, will be the fittest viruses, the ones that can spread to more people.
“We know, for example, in the two places where some worrying variants have emerged, in South Africa and Brazil, that in those parts of the world, there was already a fairly high level of antibody response from people who have been infected and recovered from. the virus.
“It wasn’t herd immunity, but there was an increasing level of seroprevalence, as we say, people with antibodies.
“And the fact that these variants have arisen there, in that kind of background, in that environment, shows us that the virus will respond to changes in the human beings that it is infecting because the fittest mutants are those that grow and predominate.” .
He added that in some parts of the world where immunity is already quite high, the virus is now spreading very rapidly and more and more people are developing antibodies.
“Over time, (the virus) will have mutations that will help it to be less controlled and more adapted viruses will appear – this is how viruses will evolve,” explained Professor Barclay.
Research is underway to assess whether the new variants are resistant to vaccines and treatments.
When asked why these variants were emerging now, he added: “I think we have reached a point a year later, and in certain parts of the world, where the density of natural immunity is sufficient for the variants to have gained advantage of fitness, and therefore more likely to emerge and spread in those parts of the world.
“In the UK it is a bit different – we have seen the UK variant derived from an immunosuppressed individual who was infected for a long time.”
Prof Barclay said there are some “key similarities” between the South African variant and the Brazilian variant that are causing some concern.
She continued: “Those mutations seem to allow the virus to escape some of the immune responses that some people produce.
“So I think it makes, you know, logical that we take some action. But as I said with this, what we are doing is science to try to support and consolidate those changes so that other people can make decisions about when to close the borders. “
The virologist explained that there are two new variants in Brazil, the most worrying of which has been detected in travelers going to Japan but has not been detected in the United Kingdom, while the other has.
Professor Barclay spoke when a new national research project was announced to study the effects of emerging coronavirus mutations.
Funded by UK Research and Innovation (UKRI), the G2P-UK National Virology Consortium will look at how mutations in the virus affect key outcomes, such as how communicable it is, the severity of the Covid-19 it causes, and the effectiveness of vaccines and treatments.
The consortium will bring together leading virologists from 10 research institutions working together with the Covid-19 Genomics UK consortium (COG-UK).
It will also work with Public Health England to boost the UK’s ability to study newly identified virus variants and quickly inform government policy.
Mutations in the virus genome occur naturally, and while some of them will have no effect, others will change how it works.
