LANSING, Mich. (AP) — A Washtenaw County woman is the first person in Michigan diagnosed with the COVID-19 variant, SARS-CoV-2 B.1.1.7., according to state health officials.

The variant was identified Saturday by the Michigan Department of Health and Human Services Bureau of Laboratories.

The woman, whose name and age were not released, recently had traveled to the United Kingdom. Washtenaw County is west of Detroit.

Close contacts of the woman have been identified and are in quarantine. Two new cases have been identified from close contacts, but it is not known if they are infected with the variant, officials said.

“The discovery of this variant in Michigan is concerning, but not unexpected,” Michigan Chief Medical Executive Dr. Joneigh Khaldun said in a statement.

The variant frequently is referred to as the U.K. variant because it is prevalent in the United Kingdom. Cases also have also been reported in Utah, Colorado, California, Georgia, Florida and New York.

COVID-19 vaccines currently approved for use are believed to be effective against this strain, health officials said. Preliminary information suggests the variant is significantly more contagious, though there is no evidence so far that it causes more severe illness or increased risk of death.

More than 535,500 cases of COVID-19 have been confirmed in Michigan and 13,804 people have died in the state due to the virus since the start of the coronavirus pandemic.