Peer interventions to improve HIV testing uptake among immigrants: A realist review

BACKGROUND: As a vulnerable group in HIV control programs, immigrants face various obstacles to HIV testing. Despite the effectiveness of peer interventions on health promotion in HIV testing, relatively little is known about how these interventions work. This realist review aims to understand why, how, and under what conditions peer interventions can improve immigrants' HIV testing uptake. METHODS: We followed the steps suggested by Pawson and colleagues for conducting the realist review. To test a initial program theory, we first systematically searched databases of PubMed, Web of Science, Scopus, Embase, and Cochrane, as well as the websites of UNAIDS, World Bank, Global Fund, WHO, and IOM. After data extraction and quality appraisal, data synthesis was conducted to explain the intervention pathways corresponding to context-mechanism-outcome configurations. RESULTS: Seventeen studies were included in the review. Peer interventions for improving immigrants' HIV testing uptake worked through four pathways: Following the improvement of communications (as a proximal mechanism): 1) increasing awareness, 2) reduced stigma, 3) improved support, and 4) increased access to services could lead to improved HIV testing uptake among immigrants. The identified mechanisms were influenced by three groups of individual/ interpersonal, service delivery, and structural factors. CONCLUSION: Peer interventions with multiple strategies to be designed and implemented considering the barriers to HIV testing and also moving beyond one-size-fits-all approaches can successfully improve the immigrants' HIV testing uptake. The refined program theory in this study can help the healthcare providers and policy-makers promote the immigrants' HIV testing uptake and reduce the risk of disease transmission.