RACHEL MARTIN, HOST:
The coronavirus is changing, and thus so are the vaccines. Vaccine manufacturer Moderna says it's creating a booster shot for its COVID-19 vaccine. The goal is to ensure that the vaccine is still highly effective against new versions of the virus that are emerging in several places around the world. Scientists are especially worried about a variant coming out of South Africa. There's growing evidence that the vaccine could be less effective against that variant.
Here to explain all of this and what it means for people getting the vaccine is NPR's global health correspondent Michaeleen Doucleff. I mean, there's a new variant, as we mentioned, coming out of South Africa. This is different from a new variant coming out of the U.K. And now there is news of a strain of the coronavirus, a new strain, coming out of Brazil. What is happening?
MICHAELEEN DOUCLEFF, BYLINE: Yes, there are three different variants, Rachel. The one from the U.K. is more contagious, and it's already circulating here in the U.S. Just as you mentioned, yesterday Minnesota officials detected a person infected with a variant from Brazil. That's the first known case of this variant in the U.S. And here's the key part - the variant from Brazil and the one circulating in South Africa share some of the same mutations, and there are signs that these mutations are helping the virus outwit or evade the immune system.
MARTIN: That sounds not great. What does that mean in practice? What does it mean when it evades the immune system?
DOUCLEFF: You know, one of the main tools the body uses to fight off viruses is antibodies, right?
DOUCLEFF: The immune system makes antibodies that recognize the virus, stick to it and then destroy it or neutralize it. Turns out the mutations in the variant from South Africa and the one from Brazil changed the surface of the virus that many antibodies like to bind to. And so scientists have been trying to figure out if the antibodies that people make to the older version of the virus will actually still work with these new variants. Penny Moore is one of the virologists leading this effort. She's at the National Institute for Communicable Diseases in South Africa. She and her team took blood from people infected with the older version and looked to see if the antibodies in the blood lost their sensitivity to the new variants.
PENNY MOORE: And that is indeed what we saw. In fact, it was really quite a dramatic drop-off in sensitivity. We saw that in half, the antibodies were significantly less effective against the new variant
DOUCLEFF: And so the implications, Rachel, of this could be big, right? You know, if a person had COVID-19 with the older version, they might be able to get infected a second time with the new variant.
MARTIN: Does that mean that the vaccines that are out there aren't going to work as well against these new variants?
DOUCLEFF: Yeah. So for the variant coming out of the U.K., it looks like the vaccines will work well. For the variants coming from South Africa and Brazil, it's a different question. Scientists don't know how well these laboratory experiments will correlate with real life. Plus, the immune system has other defenses to help fight infections besides antibodies. And so all the scientists I spoke to were optimistic and believe the vaccines will still be effective but maybe a little less so. And remember - the Moderna and Pfizer vaccines, the ones approved here in the U.S., are super effective against the old variant. So even a small drop in efficacy means the vaccines will still work.
MARTIN: Right. People should still get the vaccine regardless, then.
DOUCLEFF: Absolutely. You know, scientists I talked to say it's more important than ever to get immunized. And they point out that even if a vaccine just stops severe cases and hospitalizations, you know, that will be super helpful and save a lot of lives.
MARTIN: NPR's global health correspondent Michaeleen Doucleff. Thank you, Michaeleen.
DOUCLEFF: Thank you, Rachel.