Survival rate of HIV-exposed infants in Homa Bay County, Kenya: a prospective cohort study

Abstract

Background: Mother-to-child transmission (MTCT) of HIV is a significant public health concern in sub-Saharan Africa, accounting for most pediatric HIV infections. Despite investments in prevention programs, disparities in infant HIV-free survival persist. Homa Bay County, in Kenya, bears one of the highest HIV burdens in the country. Methods: A prospective cohort of 326 infants born to HIV-positive mothers followed for up to 18 months aimed to determine the survival rate of HEIs in Homa Bay County. Data were analyzed using Kaplan-Meier survival curves to estimate survival probabilities, Cox proportional hazards regression to identify risk factors, and Bayesian spatial survival models to assess geographic clustering of outcomes. Results: variation in HIV-free survival across sub-counties, Homa Bay Town recorded the lowest infant HIV positivity, 2.9%, higher rates observed in Karachuonyo (14.3%), Suba (14.0%), and Rangwe (10.5%). Time-to-seroconversion varied; early infections were observed in Homa Bay Town (≈5 weeks), consistent with intrauterine or intrapartum transmission; later infections were noted in Mbita and Rangwe (≈37-39 weeks), suggestive of breastfeeding-related transmission. Kaplan-Meier analysis confirmed significant differences between sub-counties (log-rank p<0.05), spatial models identified high-risk clusters in Karachuonyo, Suba, and Rangwe, with a protective effect in Ndhiwa. Conclusions: Findings highlight uneven, geographically clustered patterns of infant survival, shaped by maternal adherence to antiretroviral therapy, health system capacity, and socio-cultural practices. Tailored, spatially targeted PMTCT interventions are essential to reduce transmission and improve outcomes for HIV-exposed infants.