Do Peer Navigators Improve Initiation and Retention in HIV/VH/STI Treatment Programs for People From Key Populations? A Systematic Review of Effectiveness, Values and Preferences, and Cost.

BACKGROUND: Key populations are disproportionately affected by HIV, viral hepatitis (VH), and sexually transmitted infections (STIs) and face barriers to care. Peer navigation programs are widely used, but evidence supporting their use has not been synthesized. SETTING: Peer navigation programs for sex workers, men who have sex with men, people who inject drugs, prisoners, and trans and gender diverse people globally. METHODS: To inform World Health Organization guidelines, we conducted a systematic review of effectiveness, values and preferences, and cost studies published between January 2010 and May 2021. We searched CINAHL, PsycINFO, PubMed, and EMBASE; screened abstracts; and extracted data in duplicate. The effectiveness review included randomized controlled trials and comparative observational studies evaluating time to diagnosis or linkage to care, treatment initiation, treatment retention/completion, viral load, cure, or mortality. We assessed risk of bias and summarized findings in GRADE evidence profiles. Values and preferences and cost data were summarized descriptively. RESULTS: Four studies evaluated the effectiveness of peer navigators for key populations. All were focused on HIV; none were designed for VH or STIs. These studies showed mixed effects on linkage to care, treatment retention/completion, and viral load; no studies measured treatment initiation, cure, or mortality. Two values and preferences studies with community-based organization staff and health workers suggested peer navigators for key populations were acceptable and valued, although continued challenges remained. No cost studies were identified. CONCLUSIONS: Although limited, available studies provide moderate certainty evidence for benefits of HIV/VH/STI peer navigation programs for key populations. Further evaluations are needed.

Optimizing HIV retesting during pregnancy and postpartum in four countries: a cost-effectiveness analysis.

INTRODUCTION: HIV retesting during late pregnancy and breastfeeding can help detect new maternal infections and prevent mother-to-child HIV transmission (MTCT), but the optimal timing and cost-effectiveness of maternal retesting remain uncertain. METHODS: We constructed deterministic models to assess the health and economic impact of maternal HIV retesting on a hypothetical population of pregnant women, following initial testing in pregnancy, on MTCT in four countries: South Africa and Kenya (high/intermediate HIV prevalence), and Colombia and Ukraine (low HIV prevalence). We evaluated six scenarios with varying retesting frequencies from late in antenatal care (ANC) through nine months postpartum. We compared strategies using incremental cost-effectiveness ratios (ICERs) over a 20-year time horizon using country-specific thresholds. RESULTS: We found maternal retesting once in late ANC with catch-up testing through six weeks postpartum was cost-effective in Kenya (ICER = $166 per DALY averted) and South Africa (ICER=$289 per DALY averted). This strategy prevented 19% (Kenya) and 12% (South Africa) of infant HIV infections. Adding one or two additional retests postpartum provided smaller benefits (1 to 2 percentage point increase in infections averted versus one retest). Adding three retests during the postpartum period averted additional infections (1 to 3 percentage point increase in infections averted versus one retest) but ICERs ($7639 and in Kenya and $11 985 in South Africa) greatly exceeded the cost-effectiveness thresholds. In Colombia and Ukraine, all retesting strategies exceeded the cost-effectiveness threshold and prevented few infant infections (up to 31 and 5 infections, respectively). CONCLUSIONS: In high HIV burden settings with MTCT rates similar to those seen in Kenya and South Africa, HIV retesting once in late ANC, with subsequent intervention, is the most cost-effective strategy for preventing infant HIV infections. In these settings, two HIV retests postpartum marginally reduced MTCT and were less costly than adding three retests. Retesting in low-burden settings with MTCT rates similar to Colombia and Ukraine was not cost-effective at any time point due to very low HIV prevalence and limited breastfeeding.