ARI SHAPIRO, HOST:
The British government is submitting what many consider to be an ethically controversial entry into the race to find a COVID-19 vaccine. The U.K. will spend the equivalent of $43 million on a plan to vaccinate volunteers and then deliberately expose them to the coronavirus to see if the vaccine works. Joining us now to discuss the value of these so-called challenge studies is NPR's Joe Palca.
Hi, Joe.
JOE PALCA, BYLINE: Hi, Ari.
SHAPIRO: Why would the U.K. go this route?
PALCA: Well, think about these big studies that are going on now. You give some people a vaccine. You give other people an inert placebo. And you want to see if the vaccine group is more protected. But you can't tell people to go out and get infected, so you have to wait and hope that some of them will and enough of them will to get enough cases to make a comparison. And you wait, and you wait, and you wait, and you wait. With a challenge study, you vaccinate somebody and then expose them on purpose. And if they don't get infected or sick, then the vaccine seems to be working, and there's no guesswork about whether someone got exposed or not.
SHAPIRO: But if they do get sick, then someone has deliberately infected them with a potentially fatal disease, which doesn't seem like a great plan.
PALCA: No. Well, the idea is that you can - well, in some cases, there are treatments that will prevent the people who are - been exposed from getting sick. Of course, there's not a great treatment for COVID-19 yet. But what they do in - the project works in two stages. First, they find the absolute minimum dose that someone can be given of the virus that will make them sick, but hopefully not such a big dose that it'll make them terribly sick. That's the hope, anyway. And then once you know the dose, then you vaccinate someone, and you have to wait a few weeks. And then you challenge them. But that's how they work.
SHAPIRO: Well, apart from the risk to volunteers, which seems substantial, are there other reasons that people don't often do challenge studies like this?
PALCA: Well, yeah. I mean, first of all, you have a limited subject pool. Usually, it's a dozen or maybe a couple dozen people. And they're usually healthy, young volunteers. But even if the vaccine works for them, you want - you're making a vaccine that you want to work for everybody. So you don't have any older people. You don't have any pregnant women. You don't have small kids. And so you can't necessarily extend the results as easily to other populations. The other thing is that if there is some very rare side effect that the vaccine is actually causing, you probably won't see it in a small group of subjects.
SHAPIRO: Well, the U.K. has decided to go ahead with this plan. So when's it scheduled to start?
PALCA: Early next year if there's approval. They need to get - there's going to be a special ethical committee convened by the Medicines and Healthcare Products Regulatory Agency, which is the U.K. equivalent of the Food and Drug Administration. And they have to give their blessing before this can go forward.
SHAPIRO: Is the U.S. considering anything like this?
PALCA: Well, actually, they are. The National Institute of Allergy and Infectious Diseases has contracted with a laboratory to make a strain of the virus that they could use in a challenge study if there's a need. Now, one of the reasons you might need a study like this is if there aren't a lot of people getting infected. If there's not a lot of virus around, sometimes the only way you can test a vaccine is by actually challenging people with it. And that way, you know they're getting exposed. And so unfortunately, that's not a problem. There's plenty of virus around right now.
SHAPIRO: Yeah. All right. NPR's Joe Palca.
Thank you.
PALCA: You're welcome. Transcript provided by NPR, Copyright NPR.
