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 open reading frame [ORF] 73 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 with coinfections with hepatitis B virus (6.1% vs. 1.2% without coinfection; P<.001) and herpes simplex virus 2 (2.7% vs. 1.0%; P=.003). Among women, K8.1 seroprevalence was not significantly related to duration of sexual activity, the lifetime number of sex partners, or viral coinfections. The ORF73 EIA revealed similar but less clear-cut patterns.

Conclusions: Among men, HHV-8 transmission may occur through sexual activity, particularly sex with other men. No evidence was observed for heterosexual transmission to women.