Group-based trajectory models of integrated vaccine delivery and equity in low- and middle-income countries.

BACKGROUND: Integrated vaccine delivery - the linkage of routine vaccination with provision of other essential health services - is a hallmark of robust primary care systems that has been linked to equitable improvements in population health outcomes. METHODS: We gathered longitudinal data relating to routine immunization coverage and vaccination equity in 78 low- and middle-income countries that have ever received support from Gavi, the Vaccine Alliance, using multiple imputation to handle missing values. We then estimated several group-based trajectory models to describe the relationship between integrated vaccine delivery and vaccination equity in these countries. Finally, we used multinomial logistic regression to identify predictors of group membership. RESULTS: We identified five distinct trajectories of geographic vaccination equity across both the imputed and non-imputed datasets, along with two and four trajectories of socioeconomic vaccination equity in the imputed and non-imputed datasets, respectively. Integration was associated with reductions in the slope index of inequality of measles vaccination in the countries analyzed. Integration was also associated with an increase in the percentage of districts reporting high measles vaccination coverage. CONCLUSIONS: Integrated vaccine delivery is most strongly associated with improvements in vaccination equity in settings with high baseline levels of inequity. Continued scholarship is needed to further characterize the relationship between integration and health equity, as well as to improve measurement of vaccination coverage and integration.

Post-epidemic health system recovery: A comparative case study analysis of routine immunization programs in the Republics of Haiti and Liberia.

Large-scale epidemics in resource-constrained settings disrupt delivery of core health services, such as routine immunization. Rebuilding and strengthening routine immunization programs following epidemics is an essential step toward improving vaccine equity and averting future outbreaks. We performed a comparative case study analysis of routine immunization program recovery in Liberia and Haiti following the 2014-16 West Africa Ebola epidemic and 2010s cholera epidemic, respectively. First, we triangulated data between the peer-reviewed and grey literature; in-depth key informant interviews with subject matter experts; and quantitative metrics of population health and health system functioning. We used these data to construct thick descriptive narratives for each case. Finally, we performed a cross-case comparison by applying a thematic matrix based on the Essential Public Health Services framework to each case narrative. In Liberia, post-Ebola routine immunization coverage surpassed pre-epidemic levels, a feat attributable to investments in surveillance, comprehensive risk communication, robust political support for and leadership around immunization, and strong public-sector recovery planning. Recovery efforts in Haiti were fragmented across a broad range of non-governmental agencies. Limitations in funding, workforce development, and community engagement further impeded vaccine uptake. Consequently, Haiti reported significant disparities in subnational immunization coverage following the epidemic. This study suggests that embedding in-country expertise within outbreak response structures, respecting governmental autonomy, aligning post-epidemic recovery plans and policies, and integrating outbreak response assets into robust systems of primary care contribute to higher, more equitable levels of routine immunization coverage in resource-constrained settings recovering from epidemics.