<a href="https://academic.oup.com/jid/article/205/3/351/849519" rel="nofollow">https://academic.oup.com/jid/article/205/3/351/849519</a><p>Despite these caveats, the study provides important new information and confirms findings from prior investigations. Overall infectivity was 1–2 cases per 1000 per coital acts, similar to that reported during latency in low-income countries but higher than estimates from many industrialized countries [1, 2, 4, 5]. The HIV load in the index infected partner was the main driver of transmission, with a 2.9-fold adjusted risk of infection per log10 increment in viral load. This is somewhat higher than prior estimates of transmission risk associated with viral load [4, 10, 11], possibly because the short follow-up intervals and frequent viral load measurements allowed more precise estimates of the association between viral burden and infectivity. The male-to-female and female-to-male transmission rates per sex act were similar after adjustment for viral load, which is compatible with other studies from low-income populations that reported no gender-specific differentials in infectivity [1, 4], but is contrary to findings from high-income countries that suggest greater male than female infectivity [1]. Older age was associated with reduced transmission per sex act, as has been previously reported [2, 4], and male circumcision reduced female-to-male transmission by approximately 47%, an effect compatible with the efficacy reported in 3 randomized trials of circumcision for HIV prevention [12–14]. Herpes simplex virus type 2 infection and genital ulceration increased transmission between 2- and 2.7-fold, as reported in prior studies [1, 4, 15]. The estimated 78% protection afforded by condom use suggests a very high rate of consistent use [16], which is atypical for married couples in sub-Saharan Africa. In summary, it is reassuring that this large study by Hughes et al replicated findings from many prior studies; it also probably provides the most precise estimates of transmission per coital act during latent HIV disease.