VIDEO: COVID-19 rebound cases study

(NBC) - A recent study finds that nearly a third of people with Covid will experience a rebound of their symptoms.

Researchers from the University of California found that 27 percent of people saw their COVID symptoms return after they had initially improved.

The pre-printed study, meaning it hasn't been published in a peer-reviewed journal, also found that 12 percent of individuals tested positive again after several days of testing negative.

Researchers say this rebound occurred whether or not the person had taken the antiviral drug paxlovid and regardless of vaccination status.

Experts say that even with the rebound symptoms in some individuals, paxlovid is still working as it should by preventing life-threatening COVID.

Some scientists say one reason for the rebounds could be that symptoms often fluctuate and viral antigen in the nose fluctuates and that can happen with or without paxlovid.