Researchers studying body’s immune response to mixed COVID-19 booster shot

PITTSBURGH, Pa. (Ivanhoe Newswire) – With just under 70 percent of all Americans getting at least one COVID-19 vaccination and the Delta variant spreading in many communities, last month Pfizer asked the FDA for approval to administer a third shot to boost immunity. Meanwhile, scientists are now trying to determine if a third “booster” shot could be just what the doctor ordered.

Researchers at 12 sites across the country are studying the safety and the body’s immune response to a mixed booster shot of one of the three vaccines approved under FDA emergency use authorization. Scientists want to know if you got a Moderna or Pfizer shot would it be better to stay with one of those two or receive a J&J shot?

“So, we are studying all of the different combinations in order to answer that question,” Judy Martin, MD, a pediatric infectious disease specialist at UPMC, told Ivanhoe.

And should people who initially got one J&J shot, get a second or should they get a Pfizer or Moderna shot? Researchers are enrolling fully vaccinated adults to get a third shot. Volunteers will provide blood samples, so researchers can study immune responses. Researchers say it’s important information to have as more COVID-19 variants, like Delta, are identified.

Judy Martin, MD, elaborated, “So just like with the flu vaccine, you get a dose each year because the variance or the types of influence change; the concern is that at some point our current vaccinations might not protect us as well as they are doing right now for the variants.”

Researchers will follow participants for a year, but say they’ll have initial results by the end of this summer, in time for any possible surge of COVID in the fall.

The National Institute of Allergy and Infectious Diseases (NIAID), part of NIH, is leading and funding the study. A list of the 12 sites studying the mixed COVID booster is available on The identifier for the trial is NCT-0488-9209.

Contributors to this news report include: Cyndy McGrath, Producer; Kirk Manson, Videographer; Roque Correa, Editor.