A mutation of a COVID-19 strain that is thought to have originated in Brazil has been detected in Florida, health department officials said last week.

The Florida Sun-Sentinel reported that two cases of the so-called P2 variant have been recorded in the state so far, one in a 74-year-old and one in a 51-year-old. The strain is believed to be a slight mutation of the Brazilian one that has vexed health authorities in the country for months.

Of particular concern to authorities is the strain's mutation, which experts say allows it to reinfect patients who previously had milder cases of COVID-19 and developed antibodies, including younger people who dealt with weaker or asymptomatic cases of the disease.

"We have just two cases in Florida that have the extra mutation, and what that means remains to be seen,” Marco Salemi, a professor with the University of Florida’s Emerging Pathogens Institute, told the Sun-Sentinel. “If in a month from now we go from two cases to 500, that will be concerning."

“We don’t know if new mutations are going to make current variants more or less aggressive, which is why we have people around the world actively monitoring them,” Salemi added to the newspaper.

Roughly 40 percent of Florida's population was vaccinated as of last week. The state is still recording thousands of new cases of COVID-19 per day, though far below a previous high reached in early January.

The P1 variant, from which the P2 is thought to have mutated, was first discovered in the U.S. in January, when a Minnesota resident who returned from the country was found to have been infected.