TAMPA, Fla — Whether it's your second or third dose, doctors say it's smart to boost your COVID-19 shots.
"It's gonna be really, really important to get them," Dr. Jill Roberts, an epidemiologist with USF's College of Public Health said.
She says data shows our immunity goes away after a period of time.
"What happens over time is that our immune system just tends to become a little sluggish when responding to the different pathogens and so immunity can wane," Roberts said.
Right now, the FDA recommends those who got Johnson and Johnson's single-dose vaccine to get a boost two months after getting the shot. Those who got Pfizer and Moderna should wait 6 months following their second dose if they meet the guidelines.
Matching is fine, but virologist Dr. Michael Teng says mixing any of the three shots might be the way to go.
"Whenever you can get it would be a good thing," Teng said.
A federal clinical trial shows the immune response changes based on which dose you were vaccinated with first. Two doses of Moderna barely show a boost from either of the three vaccines, but you'll see the best response with Pfizer.
If you're fully vaccinated with Pfizer, another dose of Pfizer or Moderna will boost your antibodies the most. But the highest responses come from boosting the Johnson and Johnson vaccine. A dose of Moderna ups antibodies 76 fold and Pfizer 35.
"I would definitely mix and match J & J intentionally. I would actually actively shop around and try to get an mRNA boost," Teng said.
No matter when you get the vaccine, doctors say there's no need to get an antibody test beforehand.
"The booster shots are recommended based on the experimentally determined time at which it takes antibody to actually drop. So essentially, what you're doing is replicating the experiment that's already been done. There's no need to do that," Roberts said.