A member of the National Guard assisting at a COVID-19 mobile testing location looks out of a tent used for drive-thru tests, Tuesday, Dec. 1, 2020, in Auburn, Maine. On Tuesday Maine's CDC reported 20 deaths due to the coronavirus. Credit: Robert F. Bukaty / AP

AUGUSTA, Maine — Maine has confirmed a case of a concerning variant of the coronavirus that originated in Brazil, the state health department announced Friday.

The Brazilian strain — also known as the P1 variant — is in addition to 15 confirmed cases of a strain of the virus that originated in the United Kingdom here as well as four cases of a South African strain, according to the Maine Center for Disease Control and Prevention. Maine has tested about 5 percent of recent positive coronavirus cases for the new strains, the agency said.

The patient who tested positive for the Brazilian variant is a resident of Franklin County with no recent international travel history, according to the Maine CDC. The first case of the U.K. variant — detected in early February — was in a patient who had traveled outside this country.

All viruses mutate, resulting in many strains, and most variants are not concerning. But scientists worldwide have raised concerns about the variants from Brazil, South Africa and the U.K. as having the potential to spread more easily, lead to more severe disease and be more likely to reinfect individuals who have had the virus in the past.

Health experts have pointed to the prevalence of new strains as a possible explanation for why virus cases in Maine have remained stubbornly high even as the national vaccine rollout has accelerated and outbreaks in long-term care facilities have been all but eliminated.

Officials have also warned about less adherence to physical distancing measures due to pandemic fatigue and advised Mainers — especially those who are unvaccinated — to continue wearing face coverings and avoiding large gatherings. But Maine has continued to reduce economic restrictions, with bars and tasting rooms allowed to reopen for indoor seating Friday.

Early evidence suggests vaccines do protect against the variants, with the vaccine developed by Johnson & Johnson performing well in a South African trial. The Pfizer vaccine appeared to neutralize the virus in a lab study, Reuters reported earlier this month. As of Friday, just over 18 percent of Mainers had completed vaccinations.