(HealthDay)—The first U.S. case of a Brazilian COVID-19 variant that doctors fear can re-infect the previously sick surfaced in Minnesota in early January 2021, and the more infectious variant has since been found in four other states, a new government report says.

Known as the P.1 variant, it first appeared in a Minnesotan who’d recently traveled to southeastern Brazil, according to Melanie Firestone of the the Minnesota Department of Health and the U.S. Centers for Disease Control and Prevention, and colleagues.

That patient was hospitalized for nine days with COVID-19, and another person in the household who traveled with the person also developed symptoms and was diagnosed with the P.1 variant, the CDC report said. But contact tracing among fellow flight passengers and health professionals who cared for the Minnesota patient found no further infections.

The findings were published online March 3 in the CDC’s Morbidity and Mortality Weekly Report.

As of Wednesday, the CDC has reported 10 cases of the Brazil variant in the United States across five states: five in Florida; two in Minnesota; and one case each in Alaska, Maryland and Oklahoma.

Compared to two other more contagious variants first spotted in the United Kingdom and South Africa, research on P.1 has been slower to come since its discovery in late December, so scientists don’t really know how much to worry about it, The New York Times reported.

“I’ve been holding my breath,” Bronwyn MacInnis, an epidemiologist at the Broad Institute in Cambridge, Mass., told the newspaper.

But a series of unpublished studies reported this week that the P.1 variant has infected some people who developed natural immunity from previous bouts of COVID-19, the Times reported. Lab experiments also suggest the variant could weaken the protection provided by a Chinese vaccine now being distributed in Brazil.

P.1 was first discovered in late December in the Brazilian city of Manaus, in the Amazon jungle. The variant is currently spreading across Brazil and has been found in 24 other countries, according to the Times.

“The P.1 variant is particularly notable because of its ability to evade both vaccine-induced and natural immunity,” said Dr. Amesh Adalja, a senior scholar with the Johns Hopkins Center for Health Security, in Baltimore.

“However, it is important to remember that when it comes to this variant, vaccines—while they may not be able to stop symptomatic infection—halt what is important: serious disease, hospitalization and death,” Adalja said.

If vaccinated people start having breakthrough COVID-19 infections, that’s when we should start worrying and looking to tweak vaccines to enhance their protective capabilities, Adalja explained.

“That has not occurred yet to my knowledge, and may not occur,” Adalja said. “Nevertheless, it is important to study alternative vaccine strategies for this variant.”

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