Lisbon Cohort of Men who have Sex with Men

The Lisbon Cohort of MSM is a prospective observational study initiated in April of 2011, in partnership with CheckpointLX/GAT. 

It aims to quantify the incidence of HIV infection and its predictors in the population of men who have sex with men (MSM). 

From the perspective of quantifying the burden of infection and prevention, it aims to:

• Know the dynamics of HIV infection in MSM by quantifying its incidence;
• Monitor primary and secondary prevention behaviors, including condom use, frequency and reasons for testing and use of post- and pre-exposure prophylaxis;
• Identify critical points for preventive interventions.

From the perspective of health care provision, it aims to: 

• Identify strategies to continuously improve the testing service provided;
• Explore strategies to ensure timely linkage to health care for all people with a reactive result or who wish to access prevention.

The cohort consists of a consecutive sample of users of CheckpointLX, a free, anonymous/confidential, community-based centre for rapid testing for HIV and other STIs, targeted at MSM and delivered by peer community health workers (who are also MSM).

Men who have a non-reactive test on their first visit to the centre, who are 15 years of age or older, and who report having sex with men, are eligible for follow-up in the prospective study. Follow-up visits are scheduled according to their availability and risk assessment.

A questionnaire on health-related behaviours and sociodemographic information and an HIV rapid test are administered in each visit. Testing for syphilis, hepatitis C and hepatitis B is also offered, according to predefined criteria. Pre- and post-test counselling is offered, and in case of a reactive result, referral to a specialised consultation is ensured. In case of interest or need for access to prevention, such as post-exposure prophylaxis, pre-exposure prophylaxis, hepatitis B vaccine or the need for treatment for another infection, a referral to a specialised service is also offered.

The observational study is conducted in compliance with the ethical principles set out in the Declaration of Helsinki. Only MSM who provide written informed consent are considered participants. 

At a national level, the follow-up of this cohort of HIV-negative MSM is a valuable tool for monitoring the dynamics of HIV infection in a setting where existing prospective information has been very limited. In the international context, it also allows for a more in-depth analytical approach to population-level time trends and identification of changes in individual-level predictors shaping the HIV epidemic in MSM.