Estimating per-act HIV transmission risk: a systematic review

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• Accurate per-act HIV acquisition risk estimates are vital for effective prevention strategies.
• Previous estimates required updating to reflect current data on sexual and parenteral exposures.
• Understanding modifying factors like condom use and antiretroviral therapy is essential.

Purpose of the Study:

• To update per-act HIV transmission risk estimates.
• To assess the impact of factors like condom use, male circumcision, and antiretroviral therapy on HIV acquisition risk.
• To provide current data for HIV prevention program planning.

Main Methods:

• Conducted literature searches to identify relevant studies and meta-analyses.
• Utilized fixed-effects inverse-variance models for updated transmission risk estimates.
• Employed Poisson regression to calculate relative risks for modifying factors.

Main Results:

• HIV transmission risk is highest for blood transfusion, followed by vertical and sexual exposures.
• Sexual exposure risks vary, with receptive anal intercourse having a higher estimated risk.
• Dual use of condoms and antiretroviral treatment of the HIV-infected partner reduced HIV acquisition risk by 99.2%.

Conclusions:

• HIV acquisition risk varies significantly across different exposure types.
• Receptive anal intercourse carries an increased risk of HIV acquisition compared to previous estimates.
• Combined use of condoms and antiretroviral treatment offers the most substantial reduction in sexual HIV transmission risk.