South African variant of coronavirus may bypass existing immunity in some people

Experts increasingly fear that at least some variants of the coronavirus will pose an additional challenge to limit the spread of covid-19 through vaccination. Recent data released over the weekend suggests that a variant first found in South Africa may escape detection of antibodies in some people who had been infected with earlier versions of the virus. While it is highly unlikely that these variants will completely escape the immunity provided by the vaccine, scientists are bracing for the possibility that the vaccines will need to be adjusted to better match the new strains circulating in the population.

In mid-December, scientists in the UK and South Africa ad the emergence of new strains of the coronavirus containing disturbing genetic variations. Although the variants share some mutations, they are believed to have evolved independently. The British variant – known as 20I / 501Y.V1 or B.1.1.7 – and the South African variant – referred to as 20H / 501Y.V2 or B.1.351 – were quickly determined to be more transmissible than the strains previously common in thosand communities.

Viruses mutate all the time, but what’s made B.1.1.7, B.1.351, and other similar variants so worrying to scientists is their collection of multiple mutations linked to the spike protein, a key part of the virus that helps it enter cells to become more self-sufficient. Having enough mutations in the right places can change the relationship between a virus and its host, including its ability to infect people whose immune systems already have been trained recognize the virus, either by natural infection or by vaccination. And this is a concern that is starting to seem more real for B.1.351 in particular.

Monday, the National Institute for communicable diseases (NICD) – South Africa’s public health agency – announced the results of first work on study B.1.351 and immunity. They exposed the variant to blood samples of 44 covid-19 survivors, looking to see if the virus would survive neutralizing antibodies created against a previous infection.

“Blood samples from half of the people we tested showed that all neutralizing activity was lost,” the NICD wrote on its website. “This suggests that they may no longer be protected from reinfection.”

In over 90% of the samples there was also at least some reduction in the neutralizing capacity displayed by the antibodies. This is a more difficult finding to assess, but it could suggest that reduced immunity should be expected in people infected early in the pandemic which are then exposed to B.1.351.

These discoveries are still preliminary and based on a small sample size. And like we said many times the immunity is complicated. Antibodies are a crucial aspect of our immune system, but they are not the only one. Our T cells and B cells are also essential, and it would take a lot for a variant to bypass all of these defenses at once. This could mean that B.1.351 and similar variants can cause re-infections, but these re-infections can on average be milder than the first time. For people previously vaccinated against the coronavirus, these data suggest that B.1.351 may be able to cause disease more often than previous variants. But again, this would likely cause less (and less severe) illness on average in people vaccinated than in those without protection at all. Not all variations are the same, and their effects on immunity and transmission will depend strongly on the variant bECOMES in the community.

That said, the new data from South Africa is indeed disturbing. British and South African variants are already spread to several countries, and the experts are afraid they will soon become prevalent in these places. Over the weekend, scientists from the Centers for Disease Control and Prevention released an article predicting that variant B.1.1.7 would likely become the dominant strain in the United States by March.

Currently, the same CDC model predicts that higher levels of immunization over time will dramatically reduce transmission of all variants, including B.1.1.7 – a view widely shared by many outside scientists. Even a vaccine that loses some efficacy due to these variants will probably still have a powerful impact on reducing disease and transmission, just like vaccines against rapidly mutating viral diseases such as influenza.

But the new findings, which are expected to be presented in full by the South African government in a few weeks, indicate that we need to keep a close watch on the virus as it continues to evolve. Moderna and Pfizer / BioNTech – the companies behind the first two vaccines to reach the American public – have declared that their vaccines should be effective against the variants found so far, but they also said their vaccines can be changed to better match the newer strains if necessary. Data from the study of other human coronaviruses also suggested that the covid-19 vaccines will need to be periodically updated to follow the progress of the virus.

More than anything, these developments should highlight why it’s more important than ever to reduce our risk of catching and transmitting covid-19. No matter how many mutations the coronavirus detects, it has continued to depend on humans to continue to spread. Wear masks and avoiding close and prolonged indoor contact with large groups of people will always help to bring a faster end of the pandemic.