Risk Factors for Human Herpesvirus 8 Infection among Adults in the United States and Evidence for Sexual Transmission

Background. Human herpesvirus 8 (HHV-8) causes Kaposi sarcoma. In the United States, transmission routes for HHV-8 are uncertain. Methods. The National Health and Nutrition Examination Survey III sampled individuals from the US general population (1988–1994). We used enzyme immunoassays (EIAs) to measure HHV-8 antibodies (K8.1 and ORF73 antigens) in 13,894 surveyed adults. HHV-8 seroprevalence was examined according to sexual history and viral coinfection markers. Results. Overall, seroprevalence was low when a highly specific cutoff was used (K8.1, 1.6%; ORF73, 1.5%) but was higher when a less-specific cutoff was used (K8.1, 7.1%; ORF73, 7.4%). When the more-specific approach was used, K8.1 seroprevalence was similar in men and women. Men who have sex with men (MSM) had a higher K8.1 seroprevalence (8.2%). Among other men, K8.1 seroprevalence was marginally associated with duration of heterosexual activity (P=.1) and was positively associated with the lifetime number of sex partners (P=.04) and coinfections with hepatitis B virus (6.1% vs. 1.2% without coinfection; P