Epidemiology and prevention of sexually transmitted infections in men who have sex with men at risk of HIV.

Since 2012, the increasingly widespread promotion and uptake of HIV treatment as prevention and pre-exposure prophylaxis in men who have sex with men has been associated with increased sexually transmitted infections (STIs). However, numbers of STI cases have been rising for more than 20 years and the introduction of biomedical HIV interventions cannot explain the majority of the rises in STIs. The increases appear to have occurred mostly because of gradual changes in behaviour over many years, coupled in some settings with more condomless anal intercourse, and as a result of the increased screening for previously undetected asymptomatic infections. If control of STIs is to be improved, then a far greater emphasis on increased use of existing effective STI control strategies will be required, in addition to the investigation of new interventions. Central to effective STI control is accessible clinical care and screening services, which are currently inadequate in most settings. Insufficient action carries a risk of increased STI epidemics, including of newly resistant organisms.