There are no products available that make anal sex completely safe from the point of view of HIV acquisition, and the likelihood of this happening in the future is slim. However, in terms of risk reduction, there are practical interventions to implement, the possibility of new concepts to explore, and the promise in the future of an effective rectal microbicide.
The individual risks of anal intercourse (apart from those posed by the insertive partner) are multifactorial and may be broadly broken down to three main areas: trauma, co-infection, and products that may all facilitate inflammation and so increase HIV acquisition risk.
Trauma: The anal canal is a high pressure environment due to the combined effects of both internal and external anal sphincters and requires preparation prior to anal intercourse that may be usefully discussed in directed sex education to reduce traumatic injury.
Co-infection: Human papillomavirus is an almost ubiquitous infection in sexually active adults and is an independent risk factor for HIV acquisition by both vaginal and anal intercourse. The vaccination of both boys and girls prior to sexual debut may have the potential to reduce HIV acquisition risk.
Products: These may potentially harm and also protect. Many unregulated off the shelf sexual lubricant products have high osmolality and may contain Nononxynol 9 that can both injure and induce inflammation in rectal epithelium and so provide an environment conducive to HIV infection. However, the gel formulation of tenofovir has shown efficacy in reducing both HIV and herpes simplex virus acquisition (a cofactor for HIV infection) following vaginal application. The reduced glycerin rectal formulation of this product has been shown to be safe in a short Phase 1 study and is currently entering an extended safety Phase 2 study.
These elements will be explored during this presentation.
- Anal intercourse