Effects of improved partner notification on the transmission of HIV and N. gonorrhoea among men who have sex with men: a modelling study.

Objectives Men who have sex with men (MSM) are disproportionally affected by HIV in the Netherlands. Partner notification (PN) is an important element in controlling the transmission of sexually transmitted infections (STIs) and HIV. We investigated the effects of improving PN on the transmission of HIV and Neisseria gonorrhoeae (NG) among MSM in the Netherlands. Methods We developed an agent-based model that describes the transmission of HIV and NG among MSM. In the baseline scenario, 14.3% and 29.8% of casual and steady partners of the index case get notified and tested for HIV/STI after 3 weeks (percentage notified and tested (PNT)). We examined the following scenarios: (1) increase PNT to 41% for both partner types; (2) decrease the time between the index and the partners tested to 1 week and (3) combine scenarios 1 and 2. Effects are expressed as cumulative change from the baseline simulation over 15 years. Results Increasing PNT could lead to a decrease in gonorrhoea cases of 45% (IQR 39.9% to 49.9%), with an increase in the number of HIV/STI tests of 4.4% (IQR 1.6% to 7.3%), but no change in HIV infections (-5.4%; IQR -21% to 7.9%). Decreasing the time between tests could lead to a change in new NG infections of -14.2% (IQR -17.2% to -10%), no change in HIV infections (8.2%; IQR -1.3% to 20%) or in the number of HIV/STI tests performed (-0.4%; IQR -1.5 to 0.6%). Scenario 3 led to a change in NG infections of -56.8% (IQR -63.8% to -47.4%), no change in HIV infections (11.5%; IQR -11.1% to 33.9%) or in the number of HIV/STI tests (-0.5%; IQR: -4.9% to 4.3%). Conclusions Increasing the percentage of sexual partners notified and tested for HIV/STI may have only a small effect on HIV but could reduce the number of new NG infections substantially. However, it could lead to an increase in the number of HIV/STI tests performed.