More Infectious COVID-19 Variants Raise Questions About Vaccines' Effectiveness
RACHEL MARTIN, HOST:
All right. The emergence of new and more infectious variants of the coronavirus has raised a troubling question. Will the current crop of COVID-19 vaccines prevent these variants from causing disease? A new study out today suggests that the answer is yes. NPR's Joe Palca has more.
JOE PALCA, BYLINE: The study was fairly straightforward. Take blood from volunteers who had been given a COVID-19 vaccine and see if it contained neutralizing antibodies to the viral variants, the kind of antibodies that prevent a virus from entering cells. Dan Barouch and his colleagues at Beth Israel Deaconess Medical Center showed, as others have, that the level of neutralizing antibodies went down for some of the variants.
DAN BAROUCH: But what we also showed is that there's many other types of immune responses other than neutralizing antibodies, including binding antibodies, Fc functional antibodies and T-cell responses.
PALCA: And it's that last immune response, the T-cell response, that Barouch says is critically important because T-cells, particularly CD8 T-cells, play a crucial role in preventing illness.
BAROUCH: Those are the killer T-cells. Those are the types of T-cells that can basically seek out and destroy cells that are infected and help clear infection directly.
PALCA: They don't prevent infection. They help keep an infection from spreading. In their study, which appears in the journal Nature, Barouch says when they looked at the T-cell response to the variants...
BAROUCH: The T-cell responses actually are not reduced at all to the variants.
PALCA: Now, Barouch was testing blood from people who had been vaccinated with the Johnson & Johnson vaccine, and that may help explain why that vaccine prevented serious disease when tested in volunteers in South Africa and Brazil, where worrisome variants are circulating. But other labs have shown that both the Moderna and Pfizer vaccines can produce T-cell responses to variants of SARS-CoV-2. That's how scientists refer to the coronavirus. Marcela Maus did one of those studies. She's at Massachusetts General Hospital. It will take studies in people to be certain the vaccines will work against variants, but...
MARCELA MAUS: Anything that generates a T-cell immune response to the SARS-CoV-2, I would say, has promise as being potentially protective.
PALCA: Joe Palca, NPR News.
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