Emergence of Hepatitis C Virus Genotype 2c Infection Among Human Immunodeficiency Virus–Infected Men Who Have Sex With Men in Tokyo, Japan

We report on hepatitis C virus genotype 2c infection in 12 human immunodeficiency virus-infected men who have sex with men in Tokyo, Japan. The uncommon strains from the 12 patients were genetically clustered; they suggested an emerging outbreak in this population at high risk of sexually transmitted infections.