As many as a dozen COVID-19 variants are known to be circulating worldwide. Among them are B.1.1.7 and B.1.351, the highly transmissible strains that originated in the UK and South Africa, respectively. While more vaccines continue to move toward emergency approval worldwide, we’re still learning the effectiveness of the current vaccines against the new strains; and how the new mutations mean that even those who have already had COVID-19 may not be immune to reinfection. To explore the new strains and what they mean for vaccination efforts, future mutations, and herd immunity, the virologist Angela Rasmussen, PhD, of Georgetown University’s Center for Global Health Science and Security in Washington, DC, joins us on this week’s episode. Listen and subscribe on Apple, Stitcher, Spotify, or Google so you don’t miss the next episode. And if you like what you hear, a five-star rating goes a long way in helping us Track the Vax! Serena Marshall: We have all these new COVID strains — from Brazil, South Africa, the UK. The CDC has called them a threat to the United States. How concerned should we be? Angela Rasmussen: We need to be very concerned, but we also shouldn’t freak out. We need to make sure that these variants are not able to spread further within our population. One way to do that is through vaccination, of course. But right now, we don’t have enough vaccine supplies to vaccinate enough people quickly enough. That means that we also should be directing our energy and our concern to reducing transmission as much as possible through other means … doubling down on the precautions that we have been taking for the past year. Masking, physical distancing, avoiding enclosed spaces, not having gatherings unless they’re absolutely necessary, improving ventilation if possible, washing our hands, and disinfecting high touch surfaces — by taking all of those measures and applying them as much as we can in any given situation, we’ll be able to reduce our transmission risk until we can ramp up vaccination to the point where enough people are immunized. Serena Marshall: Is COVID mutating at a faster rate than perhaps other viruses, like the flu? Angela Rasmussen: Let me back up and explain mutation. A mutation is essentially a spelling error. When the enzyme that copies the genomes for these viruses is copying them, it can sometimes make a typo. That typo is called a mutation. Sometimes mutations have absolutely no impact at all. Sometimes they’re bad for the virus. Sometimes they give the virus an advantage. Those are the mutations that we are concerned about — the advantage ones. The ones that make the virus better at doing what viruses do, which is replicating. Any mutation that does that is going to be of concern to us. Now, coronaviruses don’t mutate as rapidly as the flu for a couple of reasons. They actually have an enzyme, in addition to the one that replicates the genome, that acts as sort of a spellchecker. And it can correct some of the mutations that are made. So it has a lower mutation rate in general than other RNA viruses, such as influenza. It also doesn’t have a segmented genome, meaning its genome is all just one big piece of RNA. Influenza has a segmented genome. Those genome segments can sort of be shuffled together in unpredictable ways, like a deck of cards. This allows new variants to emerge very rapidly. That’s not the case with coronaviruses. Serena Marshall: Are we expecting to have a U.S. virus strain? Angela Rasmussen: We already certainly know that there are variants that have emerged in the United States. Whether or not they are of concern, meaning that they have some of these mutations that will confer some type of advantage to the virus, remains to be seen. But we also are having a harder time tracking the new variants that might emerge here just because we’re not doing as much genomic surveillance as other countries. So it’s entirely possible that there could be U.S. variants that are circulating that we should be worried about, but we just don’t know about them yet. Serena Marshall: That’s kind of a terrifying thing to think about — that we could have these U.S. strains that are going to emerge. Angela Rasmussen: It’s certainly scary. What to me is scarier, though, rather than a hypothetical future U.S. variant, are the P.1, B.1.351, B.1.1.7 variants, which we know are already in the United States. Not being able to track those as well as we’d like is a concern that I have all the time. Serena Marshall: Let’s talk now about vaccines that we’ve seen ramp up throughout the country. Will that mean that we can reduce these strains and their spread? Will we be able to vaccinate our way out of these new variants? Angela Rasmussen: I don’t think we’ll be able to completely vaccinate our way out of them. Doing the math — and that’s completely ignoring all the distribution issues we have — on the number of doses that we have, it’s going to be very unlikely that we would be able to vaccinate enough people in the population to reduce the risk of these variants posed by vaccination alone. I think that if we really apply different risk-reduction measures, in addition to ramping up vaccination, that will give us a much better shot at preventing these variants from being commonplace and widespread in the United States. Serena Marshall: We’re starting to see that some of these vaccines do protect against some of these variants, but we don’t really know the full picture of protection with these new strains. So are those vaccines still going to be helpful against these strains? Angela Rasmussen: Absolutely. All the data that we have so far suggests that even in situations where the vaccines might not protect completely against symptomatic COVID, they all seem to remain effective against severe COVID-19. And that’s really the most basic and most important thing that we want these vaccines to be able to do. We want to be able to keep people out of the hospital. If somebody is going to get COVID, we want to make sure they don’t die from it. So I think that we should absolutely take the vaccines as soon as we have access to them. And that is what I’m planning to do. That’s what I’ve encouraged all of my family and friends to do as well.
