Experts are increasingly concerned that at least some variants of the coronavirus poses an additional challenge to the spread of COVID-19 by vaccination. Recent data announced over the weekend suggests that a variant first found in South Africa may escape detection by antibodies in some people who had infected with older versions of the virus. While these variants are very unlikely to completely evade the immunity afforded by vaccines, scientists are preparing for the possibility that vaccines may need to be modified to better match newer strains circulating in the population.
Half December scientists in both the UK and South Africa announced the emergence of new strains of the coronavirus with worrying genetic variations. Although the variants shared some mutations, they are believed to have evolved independent. Both the British variant – known as 20I / 501Y.V1 or B.1.1.7 – and the South African variant – called 20H / 501Y.V2 or B.1.351 – were quickly identified as being more transmissible than previously common strains in theseand communities.
Viruses are constantly mutating, but what’s made B.1.1.7, B.1.351, and other similar variants that are so troubling to scientists is their collection of multiple mutations related to the spike protein, an important part of the virus that helps it break into cells to make more of itself. Sufficient mutations in the right places can change the relationship between a virus and its host, including the ability to infect people whose immune systems are already are trained to recognize the virus, either by natural infection or vaccination. And that is a concern that is beginning to seem more real for B.1.351 in particular.
Monday, The National Institute for communicable diseases (NICD) —South Africa’s Public Health Authority — announced the results of early working study B.1.351 and immunity. They exposed the variant to blood samples of 44 covid-19 survivors, to see if the virus would survive against neutralizing antibodies created against a previous infection.
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“The blood samples from half of the people we tested showed that all neutralizing activity was lost,” said the NICD wrote on its website. “This suggests they may no longer be protected from reinfection.”
In more than 90% of the samples, there was also at least some reduction in the neutralizing ability of antibodies. That’s a more difficult finding to judge, but it might suggest that decreased immunity should be expected in infected people early in the pandemic who are subsequently exposed to B.1.351.
These findings are still preliminary and based on a small sample size. And as we said several times is immunity complicated. Antibodies are a crucial aspect of our immune system, but they are not the only part. Our T cells and B cells are also key, and it would cost a lot for each variant to get around all of these defenses at once. This could mean that B.1.351 and similar variants can cause re-infections, but those re-infections may be milder on average than the first time. For people already vaccinated against the coronavirus, these data suggest that B.1.351 may be more likely to cause disease than previous variants. But again, it would likely cause less disease (and less serious illness) on average in vaccinated people than in people without any protection. Not all variants are the same, and the effects they have on immunity and transmission will depend very much on how widespread a variant is becoming in the community.
That said, it’s new data from South Africa is indeed disturbing. The variants in the UK and South Africa are already there spread in different countries, and experts fear they will soon become predominant in these places. Over the weekend, scientists from the Centers for Disease Control and Prevention released a paper predicting that the B.1.1.7 variety would likely become the dominant species in the US in March.
At present, the same CDC model predicts that higher vaccination levels over time will significantly reduce transmission of variants, including B.1.1.7 – a view widely held by many outside scientists as well. Even a vaccine that loses effectiveness due to these variants is still likely to have a powerful effect in reducing disease and transmission, just as vaccines for rapidly mutating viral diseases such as influenza.
But these new findings, which are expected to be presented in full by the South African government within weeks, do indicate that we need to keep a close eye on the virus as it develops. Moderna and Pfizer / BioNTech – the companies behind the first two vaccines to reach the American public – have stated that their vaccines should be effective against the variants found so far, but they have also said their vaccines can be modified to better suit newer ones tribes If necessary. Data from studying other human coronaviruses also have suggested that covid-19 vaccines must be periodically updated to keep up with the changing virus.
In particular, these developments should clarify why it is more important than ever to reduce our risk of catching and passing on covid-19. It doesn’t matter how many mutations the coronavirus picks up, it remains dependent on humans to keep spreading. Wear masks and avoiding prolonged contact with large groups of people indoors will still help to bring one faster end to the pandemic.