UpdatedTue, Apr 6, 2021 at 4:41 pm PT Replies(3) Marin County Public Health's report of the county’s first two known cases of the B.1.1.7 variant comes as the county ramps up genomic sequencing. (Shutterstock) MARIN COUNTY, CA — The highly contagious U.K. coronavirus strain has been detected in Marin County, Health Officer Dr. Matt Willis confirmed Tuesday. Marin County Public Health's report of the county's first two known cases of the B.1.1.7 variant comes as the county ramps up genomic sequencing. The B.1.1.7 variant is classified as a "Variant of Concern" by the U.S. Centers for Disease Control and Prevention because it is more infectious than other strains, and it may lead to more severe disease.