“We conducted a meta-analysis to summarize rates of sexually transmitted infections among men who have sex with men (MSM) on pre-exposure prophylaxis (PrEP) for HIV versus MSM not using PrEP. Incidence rate ratios showed that MSM using PrEP were 25.3 times more likely to acquire a Neisseria gonorrhoeae infection, 11.2 times more likely to acquire a Chlamydia trachomatis infection, and 44.6 times more likely to acquire a syphilis infection versus MSM not using PrEP.”

“The safety and effectiveness of pre-exposure prophylaxis (PrEP) to prevent HIV type 1 infection among MSM has been verified in randomized controlled trials and ‘realworld’ studies. However, high incidence of sexually transmitted infections (STIs) among participants in PrEP trials has led clinicians and public health advocates to be concerned that PrEP use might lead to higher STI incidence because of increased sexual risk behavior.”1.

According to another study, sex without a condom (anal sex at last sex among men who have sex with men) has increased with both HIV-positive and negative “gay” men:

HIV-positive:
“…34.2% in the 2005 to 37.3% in 2008, to 39.8% in 2011 and to 44.5% in 2014.”

HIV-negative:
“…28.7% in 2005 to 32.8% in 2008, to 34.7% in 2011 and to 40.5% in 2014.”2.

1. “Pre-exposure prophylaxis for HIV infection and new sexually transmitted infections among men who have sex with men”
Noah Kojima, et al.
AIDS 2016, 30:2251–2252.

2. “Trends in condom use among MSM in the United States: the role of antiretroviral therapy and seroadaptive strategies.”
Paz-Bailey G, et al.
AIDS. 2016 Jul 31;30(12):1985-90.