But experts point out the new study, out of NYU's school of medicine, has not been peer reviewed and is based on blood samples from a few dozen people.
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"This type of lab study isn't really what we're looking for. We're looking for more and more real world data of vaccines over time," explained Stanford infectious disease doctor, Philip Grant, who's a principal investigator for ongoing J&J vaccine trials.
"The difference about the Delta variant in my mind is it's more infectious; it's not that it evades vaccines, it's that it is more infectious."
Dr. Grant says what matters right now is not who gets what vaccine type, but rather who ends up in the hospital with coronavirus, "I think the real world data evolving shows that people who are getting sick are unvaccinated individuals, it's not people who've gotten either the Moderna, Pfizer, or J&J vaccine."
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While still 70% effective against moderate and severe disease, in trials, J&J's vaccine was less effective than the two-dose mRNA vaccines, which feeds into questions about whether another shot is needed.
Kate Larsen: "In terms of boosters, are you expecting it's just a question of when and not if?
Dr. Philip Grant: "Absolutely, that's what I would expect."
Kate Larsen: "Would you expect that boosters for J&J would be needed sooner than boosters for Pfizer and Moderna?
Dr. Philip Grant: "Yeah, you have to expect that."
But the CDC is not recommencing any boosters yet and it's important to point out, the single dose J&J vaccine does work.
"The Johnson & Johnson vaccine gave me protection against COVID," said San Jose resident, Sarah Kishler, who is part of Dr. Grant's J&J trial. She received the vaccine in November at Stanford.
Kishler says she's protected because last month she volunteered for a separate Kaiser trial that tests for antibodies.
"I did find out the next day I had tested positive for antibodies," she said. "I thought that was a really good piece of information that seven months after I got the vaccine in the trial, I did test positive for antibodies."
Meanwhile, Dr. Grant points out J&J is studying two doses versus one. "People can be reassured that they're not being overlooked."
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