Will South African COVID variant evade vaccine?
‘We need to prevent the virus from becoming even better at infecting us’
Will the highly infectious South African COVID-19 variant, which is causing even more alarm than the new United Kingdom (U.K.) strain, resist the vaccines now being administered? How soon before it spreads and reaches the United States?
A Northwestern Medicine expert answers these questions and more below.
Ramon Lorenzo Redondo is a research assistant professor in infectious diseases at Northwestern University Feinberg School of Medicine. He studies viral evolution and the interaction between viruses and the host during infection. Redondo has led multiple studies on SARS-CoV2 evolution and population dynamics and continues to study this new virus, including studies on viral population dynamics, intra-host evolution and public health.
What is the new South African COVID-19 variant?
“This is a variant that appeared in South Africa around August, when there was a significant spike of cases in the country. Its presence has been increasing very rapidly and now is the dominant variant in the country. Preliminary data suggest this variant is able to be transmitted better to a new person because it generates a higher number of viral particles in the respiratory track. Basically, the more virus in the respiratory track, the more chances to infect another person. But there is no evidence this variant increases the severity of the disease.”
“What makes the South African different from other SARS-CoV2 variants is that it presents multiple mutations in the Spike protein, the viral protein responsible for attaching to the cells the virus infects. Although this variant has a mutation in common with the U.K. variant (the N501Y in the Spike protein), they are not related and belong to two different SARS-CoV2 lineages.”
Will this variant be resistant to COVID-19 vaccines?
“There have been some concerns about the possibility some of the mutations appearing in this new variant might make the vaccine less efficacious against it. However, there is still not enough evidence to assert this, and specific studies are needed to address the possible decrease of vaccine efficacy with this variant. More importantly, we have to take into account the vaccine generates an immunity that targets multiple regions of the virus. Therefore, it is unlikely that a few mutations in one region will compromise the full immune response against the virus.”
Why were there concerns the new variant might evade the vaccine?
“This variant has raised some concerns regarding the vaccine because preliminary studies suggested the immune response generated by other variants might not recognize this variant as well as the others. Because the current vaccines were created with a variant of SARS-CoV2 that doesn’t have the mutations appearing in these variants, some people are concerned the antibodies generated by the vaccine might not recognize these variants and might be less effective.
“An analogy of this antibody recognition would be a key and a lock. If you modify the key to the receptor slightly, it will still fit, but you might need to wiggle it a little bit and it will take longer to open the door. The same way, the antibodies generated by the vaccine might have a harder time recognizing this variant, but probably still will.
“However, we need to take several things into account: First, this study was very preliminary and needs to be confirmed. Secondly, even if this result was validated, the vaccine creates a very complex response and the antibodies recognize many regions of the virus. An analogy would be the immune system generates a full body scan of the virus. If you change your hairstyle, it will still recognize you. Only if you change completely, like viruses such as the flu do, would you be able to escape the immune system.”
“Nevertheless, it is expected the virus will evolve to try to escape to the immunity generated by the vaccine once we reach high levels of vaccination in the population. For that reason, it’s crucial to monitor the viral population worldwide by sequencing and increase our current capacity in order to attain an early detection of any appearing variants that might compromise the vaccine’s efficacy.”
Will the South African variant spread to the United States?
“To date, this South African variant has only been detected in that country, except for a few cases in the U.K. and other countries, most of them related to South African travels. This suggests for the moment it hasn’t spread outside of South Africa, as the variant has been circulating there since August. However, due to the country being a big flight hub, we can’t discount that we will see this mutation in other countries including the U.S."
Why are so many variants emerging?
“We have to remember these viruses are continuously evolving, so the appearance of new variants is a normal process. Viruses adapt, i.e. become ‘better,’ by generating variability and selecting mutations that improve their infectivity. The more infected people, the more chances for the virus to adapt and improve how it infects us.
“We need to lower the number of new cases for many reasons, including protecting people with higher risk and avoiding collapse of health systems, but also because we need to prevent the virus from becoming even better at infecting us. It is very irresponsible to allow SARS-CoV2 to adapt further, as the virus might become even more difficult to defeat.”