Spatial clustering of measles vaccination coverage among children in sub-Saharan Africa.

BACKGROUND: During the past two decades, vaccination programs have greatly reduced global morbidity and mortality due to measles, but recently this progress has stalled. Even in countries that report high vaccination coverage rates, transmission has continued, particularly in spatially clustered subpopulations with low vaccination coverage. METHODS: We examined the spatial heterogeneity of measles vaccination coverage among children aged 12-23 months in ten Sub-Saharan African countries. We used the Anselin Local Moran's I to estimate clustering of vaccination coverage based on data from Demographic and Health Surveys conducted between 2008 and 2013. We also examined the role of sociodemographic factors to explain clustering of low vaccination. RESULTS: We detected 477 spatial clusters with low vaccination coverage, many of which were located in countries with relatively high nationwide vaccination coverage rates such as Zambia and Malawi. We also found clusters in border areas with transient populations. Clustering of low vaccination coverage was related to low health education and limited access to healthcare. CONCLUSIONS: Systematically monitoring clustered populations with low vaccination coverage can inform supplemental immunization activities and strengthen elimination programs. Metrics of spatial heterogeneity should be used routinely to determine the success of immunization programs and the risk of disease persistence.

The impact of sub-national heterogeneities in demography and epidemiology on the introduction of rubella vaccination programs in Nigeria.

Rubella infection during pregnancy can result in miscarriage or infants with a constellation of birth defects known as congenital rubella syndrome (CRS). When coverage is inadequate, rubella vaccination can increase CRS cases by increasing the average age of infection. Thus, the World Health Organisation recommends that countries introducing rubella vaccine be able to vaccinate at least 80% of each birth cohort. Previous studies have focused on national-level analyses and have overlooked sub-national variation in introduction risk. We characterised the sub-national heterogeneity in rubella transmission within Nigeria and modelled local rubella vaccine introduction under different scenarios to refine the set of conditions and strategies required for safe rubella vaccine use. Across Nigeria, the basic reproduction number ranged from 2.6 to 6.2. Consequently, the conditions for safe vaccination varied across states with low-risk areas requiring coverage levels well below 80 %. In high-risk settings, inadequate routine coverage needed to be supplemented by campaigns that allowed for gradual improvements in vaccination coverage over time. Understanding local heterogeneities in both short-term and long-term epidemic dynamics can permit earlier nationwide introduction of rubella vaccination and identify sub-national areas suitable for program monitoring, program improvement and campaign support.

Democracy and Mobility: A preliminary analysis of global adherence to non-pharmaceutical interventions for COVID-19.

In the absence of vaccines or therapeutics, and with cases of COVID-19 continuing to grow each day, most countries are relying on non-pharmaceutical interventions (NPIs) to reduce the spread of SARS-CoV-2. The goal of NPIs - decreasing mobility in order to decrease contact - comes with competing socioeconomic costs and incentives that are not well-understood. Using Google's Community Mobility data, we visualized changes in mobility and explored the effect of economic, social, and governmental factors on mobility via regression. We found decreases in mobility for all movement categories except in residential areas; these changes corresponded strongly with country-specific outbreak trajectory. Mobility increased with GDP per capita, though this relationship varied among movement categories. Finally, countries with more authoritarian governments were more responsive with respect to mobility changes as local case counts increased; however, these countries were also less likely to report mobility data to Google. These preliminary findings suggest that country-specific outbreak trajectory, GDP per capita, and democracy index may be important indicators in assessing a given population's adherence to NPIs.