NOEL KING, HOST:
The Johnson & Johnson COVID-19 vaccine appears to be highly effective against the very contagious and deeply worrying Delta variant. That's according to a new direct evaluation of the vaccine. Here's NPR health correspondent Rob Stein.
ROB STEIN, BYLINE: As the Delta variant is quickly taking over around the world, the big question has been, will the vaccines protect people against this dangerous new strain? Scientists have produced strong evidence that the answer is yes for the Moderna and Pfizer vaccines. But until now, there's been no direct evidence about the one-shot Johnson & Johnson vaccine. So Dan Barouch at the Beth Israel Deaconess Medical Center in Boston studied the immune systems of people who got the shots.
DAN BAROUCH: So we looked at 20 individuals who received the J&J Ad26.COV2.S vaccine. And we looked at their binding and neutralizing antibodies in their blood, as well as their T-cell responses.
STEIN: Antibodies that can neutralize the virus and T cells that can seek out and destroy infected cells. And what they found was very reassuring. Their immune systems produced powerful responses that could easily neutralize the Delta variant in the lab. And the immune system response held steady month after month.
BAROUCH: We found that the immune responses are long lasting. Antibody and T-cell responses induced by the J&J vaccine last for at least eight months, with minimal to no evidence of decline over this time period. So this is very promising for a durable vaccine.
STEIN: But that's not all. Not only didn't the immune system response wane over time. It seemed to grow stronger.
BAROUCH: The responses against the variants actually gets better over time and actually increases over time.
STEIN: Barouch thinks this occurs when another type of immune system cell, known as a B-cell, gets better at producing powerful antibodies.
BAROUCH: They're basically learning how to make better antibodies over time, antibodies that can neutralize multiple variants over time.
STEIN: Another study conducted by Johnson & Johnson produced similar results. Now, both studies are small. But taken together, Barouch thinks people who got the Johnson & Johnson vaccine can feel confident they're protected and are unlikely to need a booster at least anytime soon. Rob Stein, NPR News. Transcript provided by NPR, Copyright NPR.
