TAMPA, Fla. (WFLA) – COVID-19 breakthrough cases are rising, and now people want to know which vaccine offers the best protection from the coronavirus.

A breakthrough case is when a fully vaccinated person gets infected with the coronavirus. The Centers for Disease Control and Prevention recently reported about 35,000 breakthrough cases per week — a small percentage of the more than 165 million Americans who are fully vaccinated.

So what are the chances of getting the virus after receiving the Pfizer, Moderna or Johnson and Johnson vaccine?

“You are a little more likely to get a breakthrough infection with Johnson & Johnson, but we’re talking little margins compared to if you’re completely unvaccinated,” USF Associate Professor of Medicine Dr. Michael Teng said.

The AP reports the two-dose Pfizer and Moderna vaccines were around 95% effective at preventing illness, while the one-dose Johnson and Johnson shot was 72% effective, though direct comparisons are difficult.

Dr. Jason Salemi, at the University of South Florida’s College of Public Health, stresses that the vaccine wasn’t designed to prevent you from getting infected, but rather to prevent you from getting extremely sick.

“There are still going to be a lot of people who are fully vaccinated who continue to test positive,” Salemi said. “If you’re hearing about a lot of people who are around you who are fully vaccinated who are testing positive, that’s OK. That is not any evidence that the vaccines don’t work.”

He added, “The difference in efficacy is not dramatic such that you should worry about waiting for one vaccine versus another.”

The CDC says vaccines prevent more than 90% of severe diseases but may be less effective at preventing infection or transmission.