January 7, 2021 – William Hanage, associate professor of epidemiology at the Harvard TH Chan School of Public Health, discusses two newly discovered coronavirus variants.
Q: There are new reports of a second coronavirus variant in South Africa – in addition to those found in the UK and other countries – that may have higher transmissibility than other strains. What can you tell us about these variants?
A: Let us first distinguish between ‘mutations’ and ‘variants’. Mutations are specific changes in the viral genome. This happens all the time and most do not make a big difference, or are actually bad for the virus. However, these variants have multiple mutations that distinguish them from the rest of the virus population.
In the last few months we have seen two variants emerge. The first ‘variant of concern’ has been reported from the UK and in recent weeks has gathered evidence that it is more communicable. The second, the so-called “501.V2” variant, spread rapidly in South Africa. Other countries have reported the presence of both variants, probably due to increased investigation and awareness. These two variants have several similarities, including a specific mutation that results in a change in the protein found. in vitro to enhance the binding affinity of the coronavirus with the receptor used by the virus to enter cells. In addition to this mutation, 501.V2 has multiple other mutations, including one that can help the virus not be so easily neutralized by restorative sera, a treatment that uses blood from an individual recovering from COVID-19 and antibodies develop.
Q: How likely, do you think, are there other variants that are more transferable, and how likely is it that one of these will end up in the US?
A: It should be noted that variants did not originate in a predictable way and that they are rare. We currently know of two and there have been more than 85 million cases of coronavirus worldwide. However, given the uncontrolled nature of the pandemic in many places, it is very likely that other variants will emerge and reach the US. Indeed, they have already done so and we have only seen those in the places where people have searched for them.
Genomic surveillance is weak in most places, including much of the US. When I recently looked at nextstrain.org – a website that monitors the development of pathogens and collects genomic data from global sources – and searched for SARS-CoV-2 taken from North Dakota, I found nothing, though North Dakota 4de in the country for the death per capita at the time. It should be a scandal that we know so little about the virus that is spreading there.
Q: How confident can we be that the currently available vaccines will be effective against any new variants? And what would be the main strategies to avoid the rapid spread of these variants?
A: At present, we have no evidence that the available vaccines will be less effective. The variety of concerns reported in the UK no longer seem likely to re-infect those we were previously infected with, suggesting that vaccines will be effective. 501. V2 does have some mutations reported elsewhere to evade elements of the immune response, but it is not clear whether its success is related to this or higher infectivity. It is important to note that vaccines work with different parts of the immune system, and even if one is reduced, the other must still be active.
In order to avoid the spread of these variants, meanwhile, we need to make sure we know where they are and are ready to respond. Then we must be prepared to impose stronger restrictions. It is noteworthy that the variety became very common in the United Kingdom in November, a period when there were relatively severe restrictions. Finally, we need vaccination. All the astonishing scientific work to produce the vaccines counts for nothing, if we do not overcome distribution issues and let people take.
– Karen Feldscher