This abstract is taken, in part, from the article summary.
The risk of acquiring HIV from a single sexual contact varies enormously, reflecting biological and behavioral characteristics of both infected and uninfected partners. This article systematically reviewed current literature on HIV transmission estimates, and developed an HIV risk score that would allow quantification of overall risk of HIV acquisition within HIV-serodiscordant partnerships. The HIV risk score enumerates the relative risk of HIV acquisition from HIV-positive partners incorporating the type and frequency of specific sex acts, the HIV plasma viral load and stage of disease, the presence of genital ulcer disease in either partner, and pregnancy, HSV-2 seropositivity, and circumcision status (men only) in the HIV-negative partner.
The authors conclude that key determinants of HIV exposure risk can be incorporated into a mathematical model in order to quantify individual relative risks of acquiring HIV. They intend for the model to facilitate comparisons within clinical trials of exposed uninfected individuals and facilitate interventions to reduce HIV transmission. In addition to providing valuable, if dense, data on the comparable risks of sexual HIV transmission, the article also gives a sense of the sheer volume of factors that influence transmission.