Non-ulcerative diseases and HPV (anogenital warts)

While evidence for the effect of GUD is generally stronger,¹ human papillomavirus (HPV) infection and non-ulcerative STIs including gonorrhoea, chlamydia and bacterial vaginosis are also linked to increased risk of HIV infection. Gonorrhoea, chlamydia and trichomoniasis have been shown to increase risk of HIV infection in women.² Gonorrhoea has caused high levels of HIV in the semen of men with undetectable plasma HIV viral loads.³

Bacterial vaginosis and schistosomiasis are discussed in later sections.

Until recently, data have been scarcer as to whether HPV infection or active genital or anal warts affects HIV risk. However, several recent prospective studies of MSM (in the US and Australia) have found that recent anal warts and anal gonorrhoea increased HIV infection risk from unprotected receptive anal intercourse⁴ and that anal HPV infection was an independent risk factor for HIV seroconversion.⁵ Moreover, a cross-sectional study of South African men found that those who had acquired HIV in the previous two years were over four times as likely to have a cancer-causing strain of HPV than men who remained HIV negative. Lower risk strains of HPV, which only cause warts, were not associated with HIV infection.⁶