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Unpacking The Variations In Vaccine Efficacy Data


We're going to start with that news about COVID-19 vaccines. New ones may soon be on the way. The drug company Johnson & Johnson announced the results of recent clinical trials for a one-shot vaccine. The company says its vaccine was 66% effective at preventing moderate to severe COVID-19.

To help us understand what all this means, we are joined once again by NPR health reporter Pien Huang. Pien, welcome back. Thank you for joining us.

PIEN HUANG, BYLINE: Thank you so much for having me, Michel.

MARTIN: So first, help us understand what it means that the Johnson & Johnson vaccine is 66% effective. That's less than both the Pfizer and Moderna vaccines, right?

HUANG: Well, Johnson & Johnson tested their vaccine on more than 40,000 people around the world - in the U.S., South Africa, Latin America. And overall, what they found was that it protected about two-thirds of those people, 66%, who got it from getting even moderately ill with COVID-19. Now, it doesn't sound as impressive as what we've seen from Pfizer and Moderna, as you mentioned. You know, their data both shows that they're around 95% effective at keeping people from getting sick from COVID at all.

But health experts say that another key number from the Johnson & Johnson vaccine is that it's 85% effective at preventing severe disease, which means the virus (ph) appears to be really good at keeping people alive and out of the hospital. And that efficacy of the vaccine for Johnson & Johnson is actually pretty similar to what we see with the flu vaccine.

MARTIN: So tell me more about that. I mean, the flu vaccine is something we tell people to get every year.

HUANG: Yeah. Well, here's Seema Lakdawala. She's a flu virologist at the University of Pittsburgh.

SEEMA LAKDAWALA: When we recommend people get a flu vaccine shot, it is not a hundred percent effective. At best, it's 80%, but normally, it's around 60.

HUANG: Lakdawalla says that even when the flu vaccine isn't perfect, it still helps a lot of people get less sick and stay out of the hospital, so it's still really useful. And if the bar wasn't already set so high by the Moderna and Pfizer vaccines, researchers say we'd be rejoicing at the J & J vaccine. And many of them still are because there are a lot of logistical problems that this vaccine could solve.

MARTIN: Well, tell me more about that. What are some of those problems, and how is the J & J vaccine different?

HUANG: Well, one of the biggest advantages is that unlike the current vaccines we're currently giving out, the J & J only takes one shot, and within seven to 10 days, it starts showing effectiveness. Dr. Anthony Fauci, chief medical adviser to the president, says there are some other key advantages.


ANTHONY FAUCI: It is very, very good with regard to cold chain requirements - namely, requiring only a refrigerator. It is inexpensive, and the company is capable of making doses in the numbers of billions.

HUANG: The chief scientific officer of Johnson & Johnson told NPR on Friday that they can deliver a billion doses this year. That could make a huge difference. I mean, the pandemic is a global problem, and a billion doses would cover around 1 in 8 people around the world. And Fauci also said that since the J & J vaccine was tested in South Africa, it also appears to be effective at protecting people against the variant strains that have cropped up there and that it keeps them from ending up in the hospital.

MARTIN: Well, you know, I don't want to, you know, put a damper on what seems to be good news, but I do want to talk about those variants for a moment. Should we be worried that the virus is outrunning the vaccine?

HUANG: Well, that is something that researchers are keeping a very close eye on. You know, they're working in labs around the clock to make sure that our vaccines and treatments work. And Pfizer and Moderna are already formulating booster shots based on specific variants, just in case the vaccines start losing effectiveness, though they still seem pretty effective right now.

But we also have other tools that could stop virus variants from emerging and taking over. Jenny Ting, an immunologist at the University of North Carolina, says the solution is to not let the virus spread.

JENNY TING: So the faster we can contain it, of course, the better it is with every method we have, you know, whether it's masking or social distance or just be careful or vaccines.

HUANG: So public health experts are really urging people to get whichever FDA-sanctioned vaccine they can get as soon as possible to minimize their chances of ending up in the hospital with COVID and to stop the virus from spreading.

MARTIN: That is NPR health reporter Pien Huang with an important update. Pien, thank you so much.

HUANG: Thank you, Michel. Transcript provided by NPR, Copyright NPR.

Pien Huang is a health reporter on the Science desk. She was NPR's first Reflect America Fellow, working with shows, desks and podcasts to bring more diverse voices to air and online.