The Centers for Disease Control and Prevention is investigating four deaths from January 2020 that may be linked to the first COVID-19 deaths in the U.S. as the agency looks to unravel the origins of the virus in the country.

According to The New York Times, the four deaths occurred in Alabama, Kansas, California and Wisconsin, and are being examined by CDC Chief of Morality Statistics Robert Anderson as he looks to understand the spread of the virus beyond China.

All four deaths were reclassified in 2021 as COVID-related, but it is unclear what the reclassification stemmed from - a person’s symptoms or blood or tissue samples, the Times said.

The earliest death was recorded in Kansas on Jan. 9, 2020, and was reclassified this spring on a person’s symptoms, the state health department said, according to the report.

A fifth death was also reclassified in Oklahoma but later removed after state officials looked into it further.

Dr. Michael Worobey, an evolutionary biologist at the University of Arizona, told the Times that there is doubt the four cases are linked to infections in the U.S., adding that the deceased most likely traveled to China, where they acquired the virus.

“My guess is that they’re probably not all real, maybe not even any of them,” Worobey said. “If any of them are real, they’d be travel-linked cases, and that’s conceivable.”

Worobey’s research suggests that COVID unlikely spread beyond China before the middle of December 2019, making non-traveler deaths in the U.S. doubtful in the months that followed, according to the Times.

If true, it would have taken several weeks for someone to get infected with the virus and die. And each case is unlikely to have been fatal, the report maintained.

“Extraordinary claims require extraordinary evidence,” Worobey told the Times.

But it is unclear if any of the four deceased traveled to China.

The earliest suspected COVID-related death was not reported until Feb. 6, 2020, but Anderson notes that COVID testing was scarce at the time.

Over 40.6 million people in the U.S. have contracted the coronavirus, with over 654,000 COVID-19 deaths, according to data from Johns Hopkins University.

Nurses check the intubation of a COVID-19 patient in Lima, Peru, which has topped 10,000 deaths Nurses check the intubation of a COVID-19 patient in Lima, Peru, which has topped 10,000 deaths Photo: AFP / ERNESTO BENAVIDES