IrsiCaixa

Background

Active collaboration between affected communities and researchers is critical for developing appropriate strategies that address community health concerns, and can also create synergies mutually beneficial to the community and the scientists involved.

The availability of well-defined cohorts with high retention rates is crucial for HIV vaccine development. Aside from representing suitable cohorts for vaccine efficacy trials, closely monitored cohorts of persons at high risk allow the detection of recent HIV infections and the detailed analysis of early immune events.

Early detection, apart from minimising late diagnosis, has been associated with reduction in new HIV infections1, and when combined with regular testing for other Sexual Transmitted Infections (STIs), sometimes asymptomatic, could further help to decrease HIV transmission.

Moreover, better understanding of the factors associated with increased or reduced susceptibility to HIV acquisition may provide the basis for novel preventive strategies.

Methods

Check-ear is a cohort study of MSM at highest risk of HIV infection, implemented within the HIVACAT Project (Catalan Project for the Development of a Vaccine against HIV) in collaboration with BCN Checkpoint (a Community-Based Centre for HIV/STI detection in Barcelona).

Individuals are selected through an initial “risk-assessment” questionnaire. Participants are followed on a quarterly basis for HIV infection, using a rapid test, and screened once a year for STIs: Syphilis, Chlamydia, Gonococcus, Hepatitis A, B and C, Human Papillomavirus (HPV), including anal cytology. Data on socio-demographics, sexual behaviour, use of drugs, history of STIs, are collected through a questionnaire every 6 months. Biological samples are collected and stored every 6 months. Participants receive extensive counselling and condoms for risk reduction.

Results

A total of 188 MSM and transgender people enrolled so far, with 4 seroconversions identified to date (all occurring within the first three visits). The most prevalent STI detected was HPV anal infection, with a high prevalence of anal dysplasia. Results are still preliminary, since the cohort has been initiated only 18 months ago, and participants are still being recruited.

Questionnaire data are being analysed to assess possible risk factors associated with HIV infection and to identify “highly exposed persistently seronegative subjects” (HEPS) for further study of potentially protective immune parameters.

Conclusion

This study shows the feasibility of effective collaborations between community and researchers, with clear advantages for both sides: participants get a periodic screening and care of the most prevalent STIs, and researchers can identify and study early HIV infections, risk factors associated to infection, immune factors associated to infection or protection, and eventually may have a group of candidates and a community already prepared to participate in future HIV vaccine clinical trials.