Estimating per-act HIV transmission risk

Abstract

Background Effective HIV prevention programs rely on accurate estimates of the per-act risk of HIV acquisition from sexual and parenteral exposures. We updated the previous risk estimates of HIV acquisition from parenteral, vertical, and sexual exposures, and assessed the modifying effects of factors including condom use, male circumcision, and antiretroviral therapy. Methods We conducted literature searches to identify new studies reporting data regarding per-act HIV transmission risk and modifying factors. Of the 7339 abstracts potentially related to per-act HIV transmission risk, three meta-analyses provided pooled per-act transmission risk probabilities and two studies provided data on modifying factors. Of the 8119 abstracts related to modifying factors, 15 relevant articles, including three meta-analyses, were included. We used fixed-effects inverse-variance models on the logarithmic scale to obtain updated estimates of certain transmission risks using data from primary studies, and employed Poisson regression to calculate relative risks with exact 95% confidence intervals for certain modifying factors. Results Risk of HIV transmission was greatest for blood transfusion, followed by vertical exposure, sexual exposures, and other parenteral exposures. Sexual exposure risks ranged from low for oral sex to 138 infections per 10 000 exposures for receptive anal intercourse. Estimated risks of HIV acquisition from sexual exposure were attenuated by 99.2% with the dual use of condoms and antiretroviral treatment of the HIV-infected partner. Conclusion The risk of HIV acquisition varied widely, and the estimates for receptive anal intercourse increased compared with previous estimates. The risk associated with sexual intercourse was reduced most substantially by the combined use of condoms and antiretroviral treatment of HIV-infected partners.

Comparison of Follicular and Luteal Phase Mucosal Markers of HIV Susceptibility in Healthy Women

“…[1][2][3][4] In regions of the world where HIV-1 incidence is highest, more women are newly infected per year than men. 5 While social, behavioral, and economic conditions are certainly factors in the increasing incidence of HIV-1 in women, there has been an emphasis on the role of endogenous 6 and exogenous 7 hormones as cofactors in HIV-1 acquisition or infection and disease progression.…”

Minimal Awareness and Stalled Uptake of Pre-Exposure Prophylaxis (PrEP) Among at Risk, HIV-Negative, Black Men Who Have Sex with Men

“…17 However, with 50,000 annual HIV infections, scale-up of PrEP will necessitate greater population uptake than what we currently observe. 18,19 In order to increase uptake of PrEP, it is critical that we focus attention on how PrEP is being embraced by populations at-risk for HIV. Our understanding of community perspectives of PrEP suggests that there are multiple limitations to accessing it, 10,11,[20][21][22][23][24] and that populations in need might not be receiving information about PrEP.…”

Human Immunodeficiency Virus

“…Unprotected receptive anal intercourse poses the greatest sexual transmission risk-more than 10 times greater than unprotected insertive anal intercourse, while receptive and insertive penile vaginal intercourse transmission risks are lower yet (5). Effective antiretroviral therapy (ART) can dramatically impact transmission risk.…”

“…For example, the risk of sexual transmission varies based on the sex act, the presence of concurrent genital ulcerative diseases like herpes simplex virus and syphilis, the source patient viral load, host viral factors, and recipient immune factors (5).…”