COLUMBUS, Ohio (WCMH) — When it comes to COVID-19, there are two things doctors are keeping an eye on right now: viral rebound and reinfection.

This is after President Joe Biden went back into isolation after testing positive for COVID-19 once again following a recent negative test.

Doctors said it’s important to know the difference between viral rebound and COVID-19 reinfection as several Ohio counties are facing high levels of COVID-19 and seeing more cases.

“Reinfection means you’ve recovered from COVID in the last 90 days and then you have gotten COVID again, that’s reinfection,” said Dr. Mahdee Sobhanie, an infectious disease doctor with the Ohio State University Wexner Medical Center. “Rebound is that same course of the illness and you have the virus come back.”

Sobhanie and Dr. Joseph Gastaldo with OhioHealth both said it is important to know the difference between the two.

The White House said Biden is currently experiencing a viral rebound after treating COVID-19 with Paxlovid, the COVID-19 pill.

“We don’t know the exact cause of why that happens,” Gastaldo said. “It’s believed that Paxlovid really inhibits the virus replication so much that after the Paxlovid five-day course ends, there’s residual virus and it begins replicating again, resulting in a positive test.”

Gastaldo added people who rebound are considered contagious. Doctors are also worried about reinfection.

They said if you had COVID earlier this year, you could get sick again and test positive because of the BA.5 variant.

“When you get a test done, whether it be an antigen test or a PCR test, you don’t know what variant you got infected with,” Gastaldo said.

Both doctors are urging communities to remain vigilant when it comes to COVID and protective measures like masking and testing.

“We saw what happened in the Delta wave, you know?” Sobhanie said. “So that’s why if you do get reinfected, the vaccines do a much better job in protecting you, especially if you’re up to date on your vaccines including boosters.”

Doctors said Paxlovid is still a good treatment to keep patients out of the hospital.

Both said more real-time data is needed to know how many people could be impacted by a viral rebound in the future.