Pentavalent vaccination in rural Kenya: coverage and geographical accessibility to health facilities using data from a community demographic and health surveillance system in Kilifi County.

Abstract Background There is substantial evidence that immunization is one of the most significant and cost-effective pillars of preventive and promotive health interventions. Effective childhood immunization coverage is thus essential in stemming persistent childhood illnesses. The main indicator of performance of the immunisation programme is the third dose of diphtheria-tetanus-pertussis (DTP3) vaccine for children, because it mirrors the completeness of a child’s immunisation schedule. Spatial access to a health facility, especially in SSA countries, is a significant determinant of DTP3 vaccination coverage as the vaccine is mainly administered during routine immunisation schedules at health facilities. Rural areas and densely populated informal settlements are most affected by poor access to healthcare services. We therefore sought to determine vaccination coverage of DTP3, estimate the travel time to health facilities offering immunisation services, and explore of its effect on immunisation coverage in one of the predominantly rural counties in the coast of Kenya. Methods Coordinates of health facilities, information on land cover, digital elevation model, and road network were used to compute spatial accessibility to immunising health facilities for eligible children within Kaloleni-Rabai Community Health Demographic Surveillance System (HDSS). To explore the effect of the travel-time on DTP3 coverage, we fitted a hierarchical multivariable model adjusting for other apriori identified confounding factors. Results Spatial access to health facilities that offer immunization services significantly affected DTP3 coverage with travel times of more than one hour to a health facility significantly associated with reduced odds of receiving DTP3 vaccine (AOR= 0.84 (95% CI 0.74 – 0.94). Conclusion Increased travel time is a significant barrier to the uptake of facility-delivered immunizations in this rural community. To improve immunisation coverage, local health authorities and policy makers in remote settings can use high resolution maps to identify areas where distance and travel time may impede achievement of high immunizations coverage and identify appropriate interventions. These could include improving the road network, establishing new health centres and/or stepping up health outreach activities that include vaccinations in hard to reach areas within the county.