Tanya Lewis: Hi, and welcome to COVID, Quickly, a Scientific American podcast series.
Josh Fischman: This is your fast-track update on the COVID pandemic. We bring you up to speed on the science behind the most urgent questions about the virus and the disease. We demystify the research and help you understand what it really means.
Lewis: I’m Tanya Lewis.
Fischman: I’m Josh Fischman.
Lewis: And we’re Scientific American’s senior health editors. Today: the omicron variant and how scientists are figuring out if it’s really bad or not …
Fischman: … and what vaccines can do to protect you against it …
Lewis: … and the latest on antiviral pills.
We have a new coronavirus variant to worry about: Omicron. The World Health Organization is alarmed, and some international travel has been restricted. What do scientists know about the variant now?
Fischman: Well, they just found Omicron last week, and it was quickly listed as a variant of concern. It didn’t get that title because it’s infected a huge number of people. Just over 300 cases with the Omicron genetic sequence were reported to a global database by the middle of this week. What’s scaring people is that it has about 50 mutations, while other variants—Delta, Beta, Alpha—have about a dozen.
Thirty of those changes are arrayed along the spike protein, which the virus uses to infect cells. The changes are in spots targeted by three types of antibodies against the virus.
But what we don’t know about Omicron far outweighs what we do know. We don’t know if it is more transmissible. We don’t know if it makes people sicker. And we don’t know if these mutations make it harder for antibodies and the immune system to spot and destroy the virus.
We’ll know the answer to that last question in about two weeks. That’s how long it takes scientists to grow samples of a variant, mix them up with antibodies from people who have been previously infected with other variants or have been vaccinated and see if those antibodies still stick as well as they used to.
Right now all we have is inferences based on other variants. Some of the mutations in Omicron are linked to less antibody stickiness in Delta, for example. Yet vaccines still protect people who get Delta from serious symptoms and hospitalization. So mutations at a particular spot are not the whole story.
Transmissibility is another unknown. Omicron showed up in dozens of people in a small area of South Africa. But looking in just that one small spot is a biased search. A wider search in other areas—which again will take a few weeks—could show Delta is still dominant.
We do know Omicron was already in the Netherlands before South African scientists identified it, and it’s shown up in many European countries and in the U.S. So it may be good at getting around.
So far this variant doesn’t appear to cause more severe illness than other forms of the virus. But it doesn’t cause less sickness either. A few doctors in South Africa have said the cases they’ve seen are mild, and that makes Omicron similar to other variants such as Delta and Beta. Most cases of any variant are mild, so this one would be particularly scary if we heard about a lot of serious illness right now. Worldwide the small fraction of serious COVID cases add up to more than five million dead.
What the new variant really shows us is this is not a pandemic with instant answers. Omicron is a brand-new version of a new-to-humans virus. How it acts is uncertain. In a week or two—which is actually pretty fast—we’ll get a better handle on it, as we did with Delta and Beta and Gamma and Mu and all the others.
One of the big concerns about Omicron is that its mutations will let it evade the immunity you get from vaccination or prior infection. What do we know about that?
Lewis: Well, Josh, as you said earlier, there are still lots of unknowns. So what we can say is mostly speculation at this point. The mutations in the spike protein are definitely concerning because that’s the part of the virus most of the vaccines target to produce antibodies. But there is cause for some optimism as well.
I spoke to Alex Sette, a professor at the La Jolla Institute for Immunology, about how worried we should be. He said that while it’s too soon to know for sure, Omicron is likely to at least partially reduce the effectiveness of the vaccines. Exactly how much is unclear. But that doesn’t mean we are starting from scratch.
When your body encounters a vaccine (or the virus itself), it doesn’t just produce antibodies—it also produces immune cells called B cells and T cells. Some of these T cells venture out and kill the virus directly. While the Omicron variant may be able to slip past antibodies, there is not a lot of data yet on whether it will evade T cells as well—Sette and his colleagues are doing experiments to find out.
The initial findings suggest that some of the T cells will be compromised by the mutations. But the majority of the fragments the cells recognize are unchanged from the original virus, so the T cells should still be able to mount some response—and that could help stave off severe disease. Getting a booster shot to top up that immune response is a good idea.
For now, we’ll have to be patient and wait for the data to come in. But Sette says we shouldn’t panic. We should keep our cool, get people vaccinated and boosted, and be careful about exposure to the virus without overreacting.
Fischman: Finally, there’s been news this week about antivirals. What’s the latest?
Lewis: Earlier this week an FDA advisory panel recommended that a Merck anti-COVID pill called molnupiravir be authorized for use in high-risk adults with mild to moderate COVID. The drug was 30 percent effective at preventing hospitalization and death when given within five days of symptom onset.
The vote was pretty close, though: 13 members voted yes, 10 no. The “no”s felt that the drug’s efficacy was somewhat disappointing, and there was some concerning data in animals that suggested a possible risk to the fetus in pregnancy. But the FDA is likely to follow the group’s recommendation and authorize the drug soon.
Another drug called Paxlovid, made by Pfizer, also showed promising results. It had an impressive 89 percent efficacy at preventing hospitalization or death when given within three days of symptom onset. Pfizer has applied for FDA authorization of that drug as well, and the agency could make a decision on that before the year’s end.
In places where people don’t have ready access to vaccines or other forms of treatment, these anti-COVID pills could be game-changers in the pandemic.
Now you’re up to speed. Thanks for joining us.
Fischman: Come back in two weeks for the next episode of COVID, Quickly! And check out SciAm.com for updated and in-depth COVID news.[The above text is a transcript of this podcast.]