Experts are increasingly concerned that at least some variants of the coronavirus pose an additional challenge to limit the spread of Covid-19 through vaccination. Recent data announced over the weekend suggests that a variant found for the first time in South Africa may escape detection of antibodies in some people who had been infected with older versions of the virus. While it is highly unlikely that these variants will completely escape the immunity provided by the vaccine, scientists are preparing for the possibility that 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 announced the emergence of new strains of the coronavirus that contained worrying genetic variations. Although the variants share some mutations, they are believed to have evolved independently. Both the UK variant – known as 20I / 501Y.V1 or B.1.1.7 – and the South Africa variant – called 20H / 501Y.V2 or B.1.351 – were quickly determined to be more transmissible than the strains previously common in theseand communities.
Viruses mutate all the time, but what’s made B.1.1.7, B.1.351, and other similar variants, so worrying for scientists is the collection of multiple mutations connected to the spike protein, a fundamental part of the virus that helps it divide into cells to produce more of itself. Sufficient mutations in the right places can change the relationship between a virus and its host, including its ability to infect people whose immune systems are already was trained to recognize the virus, either by natural infection or vaccination. And this is a concern that is starting to look more real to B.1.351 in particular.
On Monday, the National Institute for communicable diseases (NICD) – public health agency in South Africa – announced the results of initial work studying B.1.351 and immunity. They exposed the variant to blood samples from 44 covid-19 survivors, looking to see if the virus would survive against neutralizing antibodies created for a previous infection.
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“Blood samples from half of the people we tested showed that all neutralizing activity was lost,” the NICD I wrote on your website. “This suggests that they may no longer be protected from reinfection.”
In more than 90% of the samples, there was also at least some reduction in the neutralization capacity exhibited by the antibodies. This is a more difficult finding to assess, but it may suggest that some reduced immunity should be expected in infected people early in the pandemic who are then exposed to B.1.351.
These findings they are still preliminary and based on a small sample size. And as we said numerous times, immunity is complicated. Antibodies are a crucial aspect of our immune system, but they are not the only part. Our T and B cells are also critical, and it would take too long for any variant to get around all these defenses at once. This may mean that B.1.351 and similar variants can cause reinfections, but those reinfections can, on average, be milder than the first time. For people already vaccinated against the coronavirus, these data suggest that B.1.351 can cause disease more often than the previous variants. But then again, it would probably cause less illness (and less serious illness) on average in vaccinated people than in those without any protection. Not all variants are the same, and the effects they have on immunity and transmission will largely depend on the spread of a variant becomes in the community.
That said, the new South Africa data is really worrying. The UK and South Africa variants are already spreading in several countries, and experts fear they will soon become prevalent in those places. Over the weekend, scientists at the Center 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 in March.
Now, the same CDC model predicts that higher levels of vaccination over time will greatly reduce the transmission of any variants, including B.1.1.7 – an opinion widely held by many outside scientists as well. Even a vaccine that loses some effectiveness due to these variants is likely to still have a potent impact on disease reduction and transmission as much as vaccines for rapidly changing viral diseases such as influenza.
But these new findings, which are due to be presented in full by the South African government in a few weeks, indicate that we have to keep an eye on the virus as it continues to evolve. Moderna and Pfizer / BioNTech – the companies behind the first two vaccines to reach the American public – stated that their vaccines must be effective against the variants found so far, but they also said that their vaccines can be modified to better match the newest ones Deformation if necessary. Study data from other human coronaviruses also suggested that covid-19 vaccines will need to be updated periodically to monitor the evolution of the virus.
More than anything, these developments should highlight why it is more important than ever to lower the risk of capturing and transmitting covid-19. No matter how many mutations the coronavirus picks up, it hasn’t stopped relying on humans to continue spreading. Wearing masks and avoiding close and prolonged contact in closed environments with large groups of people completely will still help to bring a faster end of the pandemic.