LEILA FADEL, HOST:
More than 100 million Americans have received at least one dose of a COVID-19 vaccine, and that number is now rising by 3 million doses a day. But many people still have questions about the vaccine. How long will I be protected? Will the current vaccines protect me against the new variants of the coronavirus that are turning up? Are the vaccines safe?
NPR's Joe Palca has been covering vaccines, and he joins me now. Hi, Joe.
JOE PALCA, BYLINE: Hi, Leila.
FADEL: So let's talk about safety first. There have been reports of blood clots associated with the COVID-19 vaccine. Should people be worried?
PALCA: Well, first of all, you have to keep in mind that these blood clot reports are all coming from people who received a vaccine by AstraZeneca, and that's not one of the ones that's available in this country. The second thing is these clots are extremely rare. And while European regulators are still investigating whether there's really a link, those same regulators are saying get the vaccine because the risk of COVID is greater than the risk of blood clots. As for the vaccines available here - Moderna, Johnson & Johnson and Pfizer-BioNTech - as you said, there are - more than 100 million people have been vaccinated, and there have been no danger signals like blood clots or anything else unexpected at this point.
FADEL: So what about these new variants? Will the three vaccines that are available in this country work against those variants?
PALCA: Well, the preliminary answer seems to be yes. They clearly seem to work against the U.K. variant. The one that's concerning people is a variant that showed up first in South Africa. The good news there, I guess, is that Johnson & Johnson and Pfizer both have data from people actually vaccinated in South Africa. The Pfizer data, which came out this week, suggested that the vaccine might be 100% effective against the variant, but the number of people who participated in the study was small. The Johnson & Johnson results were slightly less promising but also showed that there was efficacy. The other thing that's happening is Moderna is beginning a trial with a new vaccine that's specifically designed to counter the South African variant. So presumably, it would boost people's immunity if they were ever exposed to it.
FADEL: So this all sounds like pretty good news. But another question is, how long will these vaccines work? Are people who are vaccinated now good for life? Is it something that will have to do like the flu, where you just get a shot every year?
PALCA: Yeah. At this point, the answer to that question just isn't clear. I've talked to a lot of people. Most seem to think that a booster of some sort may be necessary, especially if newer and more dangerous variants appear. But remember; apart from a handful of people tested very early on, most people haven't been fully vaccinated for more than a few months, so evidence for long-term effectiveness just isn't available now. There was some new data this week also from Pfizer, which looked at the six-month effectiveness in the study that they did with 40,000 volunteers. And the company says they still had an efficacy of 91.3% after six months, so that's good.
FADEL: Are we likely to see any more vaccines in this country besides the three that are already here?
PALCA: Well, possibly so. AstraZeneca has completed the kind of study that the Food and Drug Administration says it wants before issuing an emergency use authorization for its vaccine. And the company has said it plans to ask for that EUA soon. I would imagine that won't happen until the issue with the blood clots is resolved. Also, there's a vaccine made by Novavax, which is expected to finish a large study soon. And this vaccine is interesting because it works in a different way from the other three that are currently available. And going forward, it may turn out that one type of vaccine or another works better for some people than for others, so it's good to have various kinds.
FADEL: That's NPR's Joe Palca. Thanks so much.
PALCA: You're welcome.
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