Spatial-temporal trend for mother to child transmission of HIV up to infancy and during Pre-Option B+ in western Kenya, 2007-13
Introduction: Using spatial-temporal analyses to understand coverage and trends in elimination of mother-to-child transmission of HIV (eMTCT) efforts may be helpful in ensuring timely services are delivered to the right place. We present spatial-temporal analysis of 7-years of HIV early infant diagnosis data collected from 12 districts in western Kenya from January 2007 to November 2013, during pre-Option B+ use. Methods: We included in the analysis infants up to one year old. We performed trend analysis using extended Cochran–Mantel–Haenszel stratified test and logistic regression models to examine trends and associations of infant HIV status at first diagnosis with: early diagnosis (<8 weeks after birth), age at specimen collection, infant ever having breastfed, use of single dose nevirapine (sdNVP), and maternal antiretroviral therapy (ART) status. We examined these covariates and fitted spatial and spatial-temporal semi-parametric Poisson regression models to explain HIV-infection rates using R-Integrated Nested Laplace Approximation (INLA) package. We calculated new infections per 100,000 live births and used Quantum GIS to map fitted MTCT estimates for each district in Nyanza region. Results: Median age was 2 months, interquartile range (IQR) 1.5 to 5.8 months. Unadjusted pooled positive rate was 11.8% in the 7-years period and declined from 19.7% in 2007 to 7.0% in 2013, p<0.01. Uptake of testing ≤8 weeks after birth was under 50% in 2007 and increased to 64.1% by 2013, p<0.01. By 2013, the overall case rate was 447 infections per 100,000 live births. Based on Bayesian deviance information criterion comparisons, the spatial-temporal model with maternal and infant covariates was best in explaining geographical variation in MTCT. Discussion: Improved EID uptake and reduced MTCT rates are indicators of progress towards e-MTCT. Co-joined analysis of time and covariates in a spatial context provides a robust approach for explaining differences in programmatic impact over time. Conclusions: During this pre-Option B+ period, the PMTCT program in this region has not achieved e-MTCT target of ≤50 case rates per 100,000 live births. Geographical disparities in program achievements may signify gaps in spatial distribution of e-MTCT efforts and could indicate areas needing further resources and interventions.