Original title: HIV infection and unawareness among men who have sex with men in Puerto Rico: data from The National HIV behavioral surveillance system 2011-2014.

Background Unawareness of HIV infection is a public health challenge that needs to be addressed, particularly in the case of men who have sex with men (MSM), since recent data are reporting increasing rates of HIV in this population in Puerto Rico. Objectives We examined differences in the prevalence of HIV infection and unawareness among MSM in 2011 and 2014 using data from the National HIV Behavioral Surveillance System, 2011 and 2014. Methods Bivariate analyses was used to compare demographical and behavioral characteristics in both cycles (2011 and 2014). Prevalence ratio (PR) was assessed with Poisson regression models to determine changes in HIV prevalence and unawareness across cycles, using the 2011 NHBS-MSM cycle as reference group. Results A stable rate in HIV prevalence was observed in 2011 and 2014. There was a higher prevalence in 2014 than in 2011 in multiple behavioral characteristics such as age at sexual initiation, the number of sexual partners in the 12 months prior to being interviewed, HIV testing in the year prior to being interview, and the disclosure of sexual orientation to a healthcare provider. A significant decrease in HIV unawareness was reported (76.67%, 2011; 46.51%, 2014). Age-adjusted regression models showed a marginal reduction of 55% in HIV unawareness for men who disclosed their sexual orientation to their healthcare providers. Conclusion Behavioral surveillance systems in groups such as MSM in on the island will aid to monitor prospectively the effectiveness of HIV testing outreach and engagement, as well as capacity capacity-building strategies targeted towards health care providers, aimed to increase HIV testing and awareness among this group.