Factors Associated with Low Uptake of Voluntary HIV Testing and Counselling Services among Youths Aged 18–24 Years in Nakuru County, Kenya: A Systematic Review

Background: Voluntary HIV testing and counselling supports informed testing and linkage to prevention and care. Evidence specific to young adults in Nakuru County is dispersed across mixed-age studies and reports using different testing outcomes. Objective: To identify factors associated with non-use or limited uptake of voluntary HIV testing and counselling among youths aged 18–24 years in Nakuru County and assess the directness and credibility of the available evidence. Methods: A completed open-source verification search was conducted on 1 September 2026 for publications dated 1 January 2000–31 August 2026. Europe PMC exports, targeted institutional and publisher searches, and citation checking were used. Nakuru youth/student studies overlapping the target ages were retained as explicitly indirect evidence. Screening, extraction and JBI appraisal used a single reviewer workflow. Findings were synthesised without meta-analysis. Results: After three duplicate removals, 248 records were screened; 38 reports were sought, eight were not retrieved, and 30 were assessed. Eleven reports representing seven studies were included. A subgroup labelled 18–24 years reported 87/226 (38.5%) using voluntary testing, although inconsistent age labels limited interpretation. Fear of a positive result, anticipated stigma, privacy concerns, low perceived need and service experiences recurred in descriptive evidence. Adjusted findings concerned broader ages, general testing or testing intention. Selection bias, inconsistent reporting, limited confounding control and cohort overlap prevented reliable ranking of determinants. Conclusions: The verified literature supports attention to confidential, acceptable and accessible testing services, but does not establish current countywide uptake or independent determinants among 18–24-year-olds. Geographically and age-specific research with clearly defined voluntary-testing outcomes is required. The review was not registered; no funding was reported.