If you’re fully vaccinated in the US, adding an extra COVID vaccine won’t hurt, but it may not help either. New research shows mixing the Astra Zeneca and Pfizer vaccines is safe and effective.
"The AstraZeneca was never studied as a one dose," said Dr. Monica Gandhi, associate division chief at UCSF/ San Francisco General Hospital.
Gandhi, a leader in the infectious disease field, reminds us that the AstraZeneca shot, which is intended to be a two-dose vaccine, isn’t approved in the US.
"It was always supposed to be boosted for six, eight, 12 weeks. It depends on what each country decides," she told Newsy.
Johnson’s and Johnson’s vaccine does use the same technology as AZ, but they’ve been studied and shown to work as a one-dose single shot.
"Well, it's unstudied, and so what I would say is just as if as we don't have any data to inform, to inform and say we believe that the J&J is actually going to perform well, we don't have a wealth of data to say how well you'll be protected by a second vaccine,” Dr. Rochelle Walensky, Director, Centers for Disease Control and Prevention said on the Today show.
The National Institutes of Health just started recruiting people for an early phase 1/2 clinical trial to look at booster doses of different COVID-19 vaccines and how "mixing" them works-like someone fully vaccinated with J&J getting a Moderna booster, for example.
The CDC doesn’t recommend getting extra doses of vaccines. CVS and Walgreens tell Newsy, they’re going with CDC guidance for now, too.
The other part of this to keep in mind is breakthrough infections-getting sick with COVID after being vaccinated is rare.
To date, of the more than 150 million Americans fully vaccinated 4,115 have gotten a breakthrough infection. The CDC says that number is likely undercounted, but overall it's still a rare thing.
"There's no evidence that we have more breakthrough infections in this country from the Johnson and Johnson dose than we do with the MRNA vaccines," Gandhi said.
"This is scary," Dan Richard said in a video he posted to Facebook.
That was the case for Richard of Aurora, Colorado. He just returned home from the COVID-ICU. He had been fully vaccinated-with a Pfizer MRNA vaccine earlier this year.
"Wear a mask, get vaccinated. Wear a mask after you're vaccinated," he said.
Bottom line: experts say it comes down to personal choice if someone wants to get an extra dose, but the science on that? We don’t know yet.