Scientists are concerned about the Covid variant found in South Africa

On January 15, U.S. public health officials warned that a more contagious variant of the coronavirus that causes Covid-19 could dominate infections in the United States by March. That grim warning refers to B.1.1.7, a variant first identified in the UK.

But now, one week later, scientists are increasingly concerned about another variant that has emerged in South Africa.

There is evidence from several small and not yet peer-reviewed studies that mutations in the South African variant – known as 501Y.V2 and already present in at least 23 countries – may have a higher risk of Covid-19 reinfection in humans was already ill and still had to have some immunity to the disease.

Scientists have not confirmed that this variant is more contagious, although evidence points in this direction. They are also concerned that 501Y.V2 may have consequences for Covid-19 treatments. Regeneron, a company that developed a cocktail of two monoclonal antibodies as a therapy for patients with the disease, reported that 501Y.V2 could possibly evade one of the antibodies in its mixture. The drug is still effective, but subsequent mutations may reduce it less.

But perhaps the most worrying is the prospect that the mutations in the variant could limit the effectiveness of existing vaccines, one of the best tools to control the pandemic.

The results of these recent studies are a serious indication that we need to look at how well vaccines can work, ‘Penny Moore, a virologist at the National Institute of Communicable Diseases in South Africa, told Vox. Collectively, they highlight the dangers of spreading Covid-19 uncomfortably and also give them the challenges that lie ahead as the virus continues to develop.

What the 501Y.V2 coronavirus variant may mean for Covid-19 vaccines

Moore is the lead author of a recent study on 501Y.V2, Tuesday as a preview on BioRxiv. She and her team in South Africa took blood plasma samples from 44 people infected with the coronavirus during the country’s first wave of infection last summer and then checked how their antibodies react to 501Y.V2 as well as older variants.

The researchers sorted the plasma samples into categories – high and low antibody concentrations. Although antibodies may decrease after infection, this does not necessarily mean that protection fades completely. Another recent study showed that immunity due to infection in most people lasts at least five months, and that the antibodies in those who have had the virus still need to be protected against previous versions of the virus if someone becomes infected again.

In 21 cases – almost half – the antibodies were powerless against the new variant when exposed in test tubes. This was especially true for plasma of people who previously had a mild infection and lower levels of antibodies.

The findings suggest that a previous Covid-19 infection may not help individuals repel the new variant if they are exposed, especially if their previous case was mild or symptom-free.

For Fred Hutch Cancer Research Center scientist Trevor Bedford, who was not involved in the research, the study was also a possible warning sign about the vaccines. Already in the fall of this year, manufacturers will have to reformulate their shots to respond to the changes in the genetic code of the virus, he wrote on Twitter:

The specific mutation scientists are most concerned about

The 501Y.V2 variant has one particular mutation, known as E484K. This change occurs in the part of the virus, the vein protein, that fits into the receptor in human cells. The vein protein is also the main target for the currently available mRNA vaccines, from Pfizer / BioNTech and Moderna.

“This mutation sits right in the middle of a focal point in the peak,” Moore said. And it has become notorious among virologists for its ability to evade coronavirus antibodies.

Scientists have shown how this can happen in other cell culture experiments. In another BioRxiv preview published recently, researchers in the state of Washington examined how mutations alter the effectiveness of the antibody response in 11-person recovery plasma – and also found that E484K has particularly potent antibody evasion.

Other variants of concern also have the E484K mutation, including the first identified in Manaus, Brazil, known as P.1. And one case study suggests that re-infection is possible in some people when exposed to the new variant.

In a pre-print, researchers in Brazil documented the case of a 45-year-old Covid-19 patient without co-morbidities, who was re-infected with the new variant months after her first attack with the disease. The patient experienced more serious illnesses for the second time. Although it has limited evidence, it could ‘have major implications for public health policies, surveillance and vaccination strategies’, the authors wrote.

The broader context of the study is also important: After more than three-quarters of the population in Manaus were infected with the virus during a spring boom, the cases are piled up again and hospitals are filling up. Researchers suspect that re-infections with the new variant may be the driving force.

“The news is not all gloomy”

But “the news is not all grim,” said Stephen Goldstein, evolutionary virologist at the University of Utah. A preliminary print led by scientists from Rockefeller University suggested that antibodies to the vaccine may be more potent than antibodies from a previous infection. Researchers tested blood samples from 14 people who received the Moderna vaccine, and six who were vaccinated with the Pfizer / BioNTech vaccine. The researchers found that the E484K mutation, and two others found in the South African variant, were associated with a ‘small but significant’ decrease in antibody activity.

However, the antibodies induced by the vaccine, ‘says Goldstein,’ are so high to begin with that the serum was still very strong against the mutant. ‘

Moore said to fully understand the threat of vaccines for vaccines. “These studies point to a problem,” she added, “but we do not see how it translates into real life.”

There is also a large variation in immune responses among humans, Goldstein said. In the Washington article, the researchers found ‘extensive person-to-person variation’ in how the mutations affect an individual’s antibody response.

“Finally, there is cause for concern about reduced efficiency, but the efficiency does not fall off a cliff,” Goldstein said. ‘The vaccines are incredibly strong. … As [they go] from 95% [efficacy] to 85% or even a little lower, we are still in good condition. That is why researchers and public health officials are calling for everyone to be vaccinated as soon as possible.

Nevertheless, Moore warns: ‘From an immune escape point of view, the variants first detected in Brazil and South Africa are more worrying, but this is just the beginning. This is our first indication that this virus can and does change. ”

It is possible that if we learn more, even the E484K mutation will not undermine the vaccines. But there may also be other changes to the virus lurking or developing there, which will escape even vaccine-induced antibodies. “So many people are now infected that it’s a race – the virus now has the opportunity to mutate,” Moore said, “so it can take the steps on the road to escaping immune more easily.”