New Halloween ‘Scariant’ Variants and Boosting Your Immunity: COVID, Quickly, Episode 41

Tanya Lewis: Hello and welcome to Covid Quickly, a series of podcasts from Scientific American!

Josh Fisherman: This is your quick update on the COVID pandemic. We bring you up to speed on the science behind the most pressing questions about the virus and the disease. We demystify research and help you understand what it really means.

Luis: I am Tanya Lewis.

fisherman: I’m Josh Fischman.

Luis: And we’re the senior health editors at Scientific American. Today, we are going to discuss the new variants and sub-variants alphabet soup that will probably be present this winter…

fisherman: And we’ll talk about how boosters add protection even if you’ve already had COVID.

fisherman: We are heading into another pandemic winter. Although completely new variants of the COVID virus have not yet emerged, there are several new sub-variants of Omicron. You call them Halloween Scariants, Tanya. What do we know so far?

Luis: The Omicron variant first appeared last fall, and over the past year, COVID cases have been primarily driven by different versions of Omicron. First it was B.1.1.529. Then there was BA.1, BA.2 and BA.3, then BA.4 and BA.5.

There are some new kids on the block now: There’s BA.4.6, which descends from BA.4 and accounts for about 12 percent of US COVID cases, and there’s BQ.1 and BQ.1.1, which together they account for more than 11 percent of cases, according to the CDC’s variant tracker. And those proportions are constantly growing.

Meanwhile, in Singapore, a subvariant called XBB has been driving a surge in cases and may be the most immunoevasive variant we’ve seen so far.

fisherman: So at least 4 newbies. How worried should we be?

Luis: Anthony Fauci, Biden’s top medical adviser, called them “problematic.” Like other variants before them, they are growing fast. And at least in the case of BQ.1.1, it appears to be better at evading our immunity from previous infection or vaccination, although vaccines should still offer protection.

Another concern involves monoclonal antibody treatments, as we discussed in the previous show. One given prophylactically to immunocompromised people, known as Evusheld, is not effective against the BA.4.6 variant. And another antibody drug called Bebtelovimab, of which the US has already ordered 60,000 doses, is not effective against BQ.1, the FDA said.

fisherman: That’s bad news for people whose immune systems can’t mount a strong response to vaccines.

Luis: That’s how it is. Biden administration officials are in talks to develop alternatives, but it’s unclear if they’ll arrive in time for a winter surge.

fisherman: Do the experts think we’re headed for another surge? And what role will the new variants play?

Luis: COVID cases are already rising again in Europe, which is usually a few weeks earlier than the US. So I’d say the chances of us seeing another rise are pretty good. But this was happening even before the new variants hit the scene. So some people think variants will just speed things up.

fisherman: So how can people protect themselves?

Luis: The best thing you can do is get your booster shot. The new bivalent booster protects you against the original SARS-CoV-2 strain and Omicron’s BA.4 and BA.5 subvariants, and likely provides some protection against newer variants as well. However, as of a couple of weeks ago, only about 5 percent of eligible people in the US had received the vaccine.

fisherman: That leaves a lot of people unprotected.

Luis: it does. And many young children have not even been vaccinated. But there’s still time to get one before the holidays, or the turkey might not be the only thing on the table.

Luis: We were talking about how few people are getting new booster shots. There are many possible reasons. Many people are simply not as worried about COVID anymore, and more and more have contracted and recovered from it. Some may think that they now have natural immunity against new infections. They?

fisherman: Something like. I mean, yes, natural immunity is a real thing. But research shows it’s not as strong as what scientists now call “hybrid immunity,” which is an older infection plus a new booster.

Luis: Does this mean that people who were infected in the past AND received a vaccine have better protection?

fisherman: Yes. Some of the best data on this comes from a large study conducted in Qatar and published this summer in the New England Journal of Medicine. He tracked about 150,000 people. Qatar has a very strong system of national health registries. So the researchers were able to learn who was infected or reinfected with Omicron and when. And they had records of who got vaccinated with the Pfizer or Moderna shots, or who didn’t get vaccinated at all.

Luis: Did you find any important difference?

fisherman: They did it. First, unvaccinated people had the highest risk of infection, and that’s not really a surprise. People with a previous infection reduced the risk of a new infection by about 50 percent.

And people who only had the original two-injection regimen had a similar risk. Scientists think that’s because people got those shots about 8 months earlier, so their immunity went down.

However, the big advantage was for people who had a previous infection more Three shots Those are the two original shots plus a booster. That reduced the chances of reinfection by 80 percent. And that was true for the Pfizer and Moderna vaccines.

Luis: That’s a really amazing benefit. Did it endure severe illness, keeping people out of hospital and reducing death rates?

fisherman: Did. Hybrid immunity like this delayed serious illnesses, again by about 80 percent.

Luis: Even among people without previous infections, a booster shot helps.

fisherman: Yes, it reduces many of your symptoms. And as someone who was recently on COVID bed rest for two weeks, I can tell you that fewer symptoms is a big deal.

The boosting data comes from a different study, a 5-month look at some 1,100 healthcare workers, that just appeared in JAMA. Those who received a booster, in addition to the original two injections, were less likely to have a fever or chills if infected with Omicron. They were less likely to need medical attention and could take care of themselves at home. They also lost fewer hours of work. All of this is compared to people who were not vaccinated at all.

Luis: Do the boosters do anything about the risk of transmission? The chances of transmitting the infection to other people?

fisherman: They seem to help. They reduced viral load (how much virus you have in your body) by about a third, compared to unvaccinated people. Now, lower viral load does not automatically equate to lower transmission, the scientists noted. But other studies have made that link.

And about 20 percent of the people with Omicron infections in this study had no symptoms, so they didn’t know they had the virus and were probably hanging out with other people.

Luis: So that in itself increases the chance of transmission.

fisherman: it does. So boosters help in various ways. And, like you said, now is the time to go out and get one.

Luis: You are now up to date. Thank you for joining us. Our show is produced by Jeff Delviscio and Tulika Bose.

fisherman: Check back in two weeks for the next episode of COVID, Quickly! And visit for up-to-date and detailed COVID news.

[The above text is a transcript of this podcast.]

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