Penn researcher weighs in on potential COVID-19 vaccine booster shots

PHILADELPHIA (WPVI) -- There's more confusion over if and when we'll need a COVID-19 booster shot.

The CDC and FDA both say that "fully vaccinated Americans do not need a booster shot at this time." But Pfizer announced it will ask the FDA for authorization of a third booster shot of its COVID-19 vaccine, timed for 6 to 12 months after the second dose.

John Wherry, Ph. D. is director of Penn Medicine's Institute for Immunology. He says vaccine companies want to be prepared in case immunity starts to wane but right now protection is holding.

"Right now the immunologic data really supports the idea that immunity might be a couple years, even 3 to 5 years, and we just have to wait and see if that matches what we see in the real world with new infections rising in people who got vaccinated," Dr. Wherry said.

So far, what we are seeing with those breakthrough cases of people who are fully vaccinated but still get infected is that most are mild cases and do not require hospital care, even with the Delta variant.

Dr. Wherry says if that starts to change, that would be a sign we need a booster shot, but that is not the case right now.