HIV surveillance and research for migrant populations: a protocol integrating respondent-driven sampling, case finding, and medicolegal services for Venezuelans living in Colombia (Preprint)
BACKGROUND Epidemiologic research among migrant populations is limited by logistical, methodological, and ethical challenges, but necessary for informing public health and humanitarian programming. OBJECTIVE We describe a methodology to estimate HIV prevalence among Venezuelan migrants in Colombia. METHODS Respondent-driven sampling (RDS), a non-probability sampling method, was selected for attributes of reaching highly networked populations without sampling frames and analytic methods that permit estimation of population parameters. RDS was modified to permit electronic referral of peers via SMS and Whatsapp. Participants complete socio-behavioral surveys and rapid HIV and syphilis screening tests with confirmatory testing. HIV treatment is not available for migrants who have entered Colombia through irregular pathways; thus, medicolegal services integrated into post-test counseling provide staff lawyers and legal assistance to participants diagnosed with HIV or syphilis for sustained access to treatment through the national health system. Case finding is integrated into RDS to allow partner referral. The study is implemented by a local community-based organization providing HIV support services and related legal services for Venezuelans in Colombia. RESULTS Data collection launched in four cities in July and August 2021. As of November 2021, 3,105 of the target 6,100 participants were enrolled. CONCLUSIONS Tailored methods that combine community-led efforts with innovations in sampling and linkage to care can aid in advancing health research for migrant and displaced populations. Worldwide trends in displacement and migration underscore the value of improved methods for translation to humanitarian and public health programming.