Advanced Search Abstract Background The human immunodeficiency virus HIV infectiousness of anal intercourse AI has not been systematically reviewed, despite its cheloo psd driving HIV epidemics among men who have sex with men MSM and its potential contribution to heterosexual spread. PubMed was searched to September Results A total of 62 titles were searched; four publications reporting per-act and 12 reporting per-partner transmission estimates were included.
Overall, random effects model summary estimates were 1.
Our modelling demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time.
AI may substantially increase HIV transmission risk even if the infected partner is receiving HAART; however, predictions are highly sensitive to infectiousness assumptions based on viral load.
Conclusions Unprotected AI is a high-risk practice for HIV transmission, probably with substantial variation in infectiousness. The significant heterogeneity between infectiousness estimates means that pooled AI HIV transmission probabilities should be used with caution.
Recent reported rises in AI among heterosexuals suggest a greater understanding of the role AI plays in heterosexual sex lives may be increasingly important for HIV prevention.