Relationship Between Kaposi Sarcoma–Associated Herpesvirus and HIV—Reply

In Reply: We agree with Dr O'Brien and colleagues that it can often be problematic to infer incidence from prevalence data. As we noted, our data are not inconsistent with some increase in KSHV prevalence with the first wave of HIV infection. Our principal objective in documenting the robust prevalence of KSHV in 1978 in HIV-uninfected men, however, was not to make a strict comparison with 1984 and 1985, but rather to show that KSHV infection was probably not introduced recently in homosexual men. This has implications for understanding KSHV transmission. If acts that are practiced by both homosexuals and heterosexuals, such as kissing, are significant routes of KSHV transmission, KSHV would likely be widespread in heterosexual populations, but actual prevalence estimates range from 0% to 9%.^1- 3 Low prevalence in heterosexual groups despite spread by kissing would be plausible if KSHV were recently introduced, but our data from 1978 do not support this.