Understanding the Decline of HIV Incidence: Insights from Structural Equation Modeling of Social and Biological Factors

Aim: Nigeria ranks among the countries with a high burden of Human Immunodeficiency Virus (HIV), though national incidence and prevalence have declined in recent years. Ekiti State has consistently shown lower HIV rates compared to other regions, but the specific drivers of this perceived decline remain underexplored. This study aimed to identify the key social, behavioral, and biological factors contributing to the declining HIV incidence in Ekiti State, Nigeria, using Structural Equation Modelling (SEM).Material and Methods: A cross-sectional survey was conducted from January to March 2023 among 448 knowledgeable informants (health professionals from state and local AIDS control agencies, medical personnel, and students). Data on perceived HIV incidence and contributing factors were collected via a structured questionnaire. Confirmatory Factor Analysis and SEM were performed using AMOS software to test hypothesized paths from latent constructs (social factors, e.g., condom promotion and education campaigns; sexual behavioral factors, e.g., reductions in concurrent partners; biological factors, e.g., antiretroviral therapy access and STI reductions) to perceived declining incidence.Results: Social (β = 0.356, p < 0.001) and biological (β = 0.309, p < 0.001) factors were significantly associated with perceived decline in HIV incidence, while sexual behavioral factors were not (β = 0.019, p > 0.05). The model demonstrated good fit (CFI = 0.987, RMSEA = 0.030, χ²/df = 1.389).Conclusion: The perceived reduction in HIV incidence in Ekiti State is primarily associated with social and biological interventions. These findings highlight the value of integrated public health approaches and support efforts toward Sustainable Development Goal 3 (Good health and well-being).