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Since the novel coronavirus first appeared in Wuhan, China in late 2019, it has mutated thousands of times, resulting in countless variants. While this may sound alarming, it is not surprising: all viruses mutate and compared to other common viruses, the speed at which the coronavirus undergoes this natural process is quite slow. But in recent months, a number of notable variants have surfaced, prompting researchers for some reason to sound the alarm: a British variant, a South African variant, a Brazilian variant, and a variant found in California.
While each of the aforementioned variants carries its own risks, both the UK and South African variants appear to involve significantly higher transmission speeds, current research shows, while the Brazilian variant has sparked a wave of cases where the virus previously infected huge numbers. last spring – of major concern is whether the available COVID-19 vaccines are effective against the mutations. To better understand the variants and exactly how concerned we should be, the Cut spoke to Michael Worobey, a professor of evolutionary biology at the University of Arizona who studies the evolution of flu viruses.
This interview is slightly concise and edited.
The main varieties we are hearing about now are the British variety, the South African variety, the Brazilian variety, and the variety found in California. Are there any others that should be on our radar?
Those are pretty much the big ones right now.
And what do we know about their transfer and death rates?
The British variant appears to be significantly more transmissible – as much as 50 percent higher – and there is some evidence that it generates a higher amount of virus in the nose and throat of people who are infected, which is probably why it has a faster transmission rate. . There is also fairly compelling evidence that it also causes a higher death rate. My graduates and I posted a science article [that has yet to be peer-reviewed] showing that the British variant probably came about in November in both California and Florida. So it has had a head start.
The South African variant also appears to be more transferable – as much as the UK variant, if not more. I’m not sure where things stand in terms of death rate, but it wouldn’t be surprising if it were on par with the UK variant. At the moment we do not really have good information about the Brazilian variant or the California variant. However, with the Brazilian variant judging by the mutations it has, which are some of the same that we think cause the increased transmissibility in the British and the South African, I wouldn’t be surprised if it were more transmissible.
Of course, you don’t want any of these rates to be high, but is one more worrisome than the other?
Let’s start with the death rate. Imagine that the virus infects a hundred people. How many of them will die? Now, to get in the weeds a little bit, the death rate isn’t a set constant. For example, if you are in a European population where quite a few people are on the older end of the spectrum, the death rate will be higher than in countries where there are not that many elderly people, because the virus is much milder in younger people. The transmission speed determines how many people get the infection.
Even without a higher death rate, with a higher transfer rate, more people will die than would have died if that variant had not emerged. And that is dramatic. In England, hospitals are filled with patients who wouldn’t have been there if the variant hadn’t been so transmissible, and that’s what awaits us here in the US. The variant has its hooks in us. In three or four months, almost all if not all cases of the virus will be caused by variants.
Last week, Moderna announced that its vaccine was effective in protecting against the British and South African variants, although efficacy for the latter did decline. Still, the company is said that the neutralizing antibodies were generated by the vaccine. But now both Moderna and Pfizer are developing booster shots to add to their vaccine regimens, specifically to protect against variants. How do we process this information? Are the approved COVID-19 vaccines effective against the variants, or are they slowly becoming obsolete?
I think the companies are just being careful and starting that work in case it’s useful, but at the same time, the studies going on at the same time indicate that, thankfully, that might not even be necessary. At present, there is no evidence that the vaccines will fail against these new variants. In fact, the vaccine appears to elicit a more potent immune response than a natural infection.
If we already know that the available vaccines are 95 percent effective, in the best scenario some people will become infected after vaccination. Well, I do think that if you take the vaccine generated with the original formulation and use it in an area with a variant with an escape mutation, it will be slightly less effective. But it is difficult to quantify how much less effective it is. [Editor’s note: This interview was conducted before Johnson & Johnson unveiled a summary of the results for its global vaccine trial, effectively corroborating Worobey’s assessment: In the U.S., the vaccine was 72 percent effective against moderate to severe cases; in South Africa, where most COVID-19 infections are caused by that country’s variant, the efficacy rate dropped to 57 percent.]
There are some reports about the Brazilian variant possible cause reinfection. Could it evade the antibodies made against the previous version of the virus?
The Brazilian variant has a certain mutation called E484K, and we know from laboratory experiments that this mutation can allow the virus to escape certain antibody reactions. For a few people, that can make a difference and allow them to re-infect, but the good news is that, as far as we can tell, the vaccines have enough buffer in terms of how powerful the antibody response they generate. For most people, that mutation probably won’t let the virus completely escape that response.
I would also like to comment on the reports that the British variant may have originated in an immunocompromised patient. Can you clarify this connection for me?
Yep, that’s what most people think happened. The British variant has so many mutations that it doesn’t fit what we call the molecular clock of viruses, where we expect a mutation of this virus about every two weeks. This virus has just picked up so many mutations that it looks like something that has traveled back from the future.
The variant has a number of amino acids deleted in the spike protein, and those same mutations – the deletion at sites 69 and 70 of the spike protein – have occurred multiple times in people who are immunocompromised and chronically infected with the virus. People’s immune systems are not working properly; they can’t get rid of the infection like most people, so they get infected for months. And in several cases, these people have been treated with so-called restorative plasma, which is basically just antibodies from someone who’s been infected.
This should certainly inform how we treat immunocompromised people, who could be a melting pot for the generation of the next worrying variant. We really have to be very careful about the onward transmission of chronically infected patients. If they are in the hospital, it means that they must be isolated and employ very strict procedures to limit interaction with staff or visitors.
Do you think we’ll see other variants popping up that are just as disturbing?
These will not be the last variants we hear. Once we vaccinate everyone, the virus will experience a much stronger selective power to come up with new variants that escape immunity to some degree. Where there is a major rollout of vaccines, we will see that mutation process accelerate in the coming months. Now how concerned should we be? Again, we should be fairly reassured that the vaccine still holds up for most people. But again, the virus will also continue to develop. I think we will have to update the vaccines at some point in the future, but when exactly is hard to say.
So what exactly do we do with this information? How should it inform our actions in the near future?
For me it’s all the more reason to keep your face mask on, and hope the people around you do too. That just got so much more important. If we didn’t have the potential cavalry of vaccines on the horizon, we would have a lot of trouble in this country in March and April. So let’s hope the logistical issues and the fuck-ups that have characterized so much of our country’s response to the virus can be ironed out.