To assess associations between Kaposi sarcoma–associated herpesvirus
(KSHV) infection, HIV infection, and sexual behavior, Osmond and colleagues
studied homosexual male cohorts in San Francisco at points during 1978 through
1996. Prevalence of KSHV infection was high at the start of the study. Reduction
in unprotected anal intercourse coincided with decline in HIV, but not in
KSHV, prevalence. Although observed at an ecological level, behaviors remaining
highly prevalent, such as unprotected oral intercourse, may be more likely
to account for KSHV transmission.