LOCAL DISCREPANCIES IN MEASLES VACCINATION OPPORTUNITIES: RESULTS OF POPULATION-BASED SURVEYS IN SUB-SAHARAN AFRICA

Sunday, 2nd of March 2014

[source]BMC Public Health[|source]

In order to sustain gains in measles control and further reduce mortality, an understanding of whether each of these vaccination opportunities reaches children is essential. Vaccination coverage is the key indicator to measure the progress of measles control. Ministries of Health (MoH) report annual administrative coverage based on population estimates. In many contexts, however, population estimates, are often not up-to-date, resulting in biased or inaccurate estimates. Consequently, population-based surveys are often the best available means to estimate vaccination coverage at both local and national levels.

In this report, the authors present a secondary data analysis of different community coverage surveys to describe measles vaccine coverage through different vaccination opportunities in different settings in sub-Saharan African countries. The paper demonstrates that community surveys are the best in estimating coverage for immunization.   More details are accessible at:  http://www.biomedcentral.com/content/pdf/1471-2458-14-193.pdf

 

Abstract

BACKGROUND: The World Health Organization recommends African children receive two doses of measles containing vaccine (MCV) through routine programs or supplemental immunization activities (SIA). Moreover, children have an additional opportunity to receive MCV through outbreak response immunization (ORI) mass campaigns in certain contexts. Here, we present the results of MCV coverage by dose estimated through surveys conducted after outbreak response in diverse settings in Sub-Saharan Africa.

METHODS: We included 24 household-based surveys conducted in six countries after a non-selective mass vaccination campaign. In the majority (22/24), the survey sample was selected using probability proportional to size cluster-based sampling. Others used Lot Quality Assurance Sampling.

RESULTS: In total, data were collected on 60,895 children from 2005 to 2011. Routine coverage varied between countries (>95% in Malawi and Kirundo province (Burundi) while <35% in NDjamena (Chad) in 2005), within a country and over time. SIA coverage was <75% in most settings. ORI coverage ranged from >95% in Malawi to 71.4% [95% CI: 68.9-73.8] in NDjamena (Chad) in 2005.In five sites, >5% of children remained unvaccinated after several opportunities. Conversely, in Malawi and DRC, over half of the children eligible for the last SIA received a third dose of MCV.

CONCLUSIONS: Control pre-elimination targets were still not reached, contributing to the occurrence of repeated measles outbreak in the Sub-Saharan African countries reported here. Although children receiving a dose of MCV through outbreak response benefit from the intervention, ensuring that programs effectively target hard to reach children remains the cornerstone of measles control.