Local discrepancies in measles vaccination opportunities: Results of population-based surveys in Sub-Saharan Africa

BMC Public Health (Impact Factor: 2.26). 02/2014; 14(1):193. DOI: 10.1186/1471-2458-14-193
Source: PubMed


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.
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 N'Djamena (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 N'Djamena (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.
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.

Download full-text


Available from: Lise Grout, Mar 02, 2014
  • Source
    • "Between 2010 and 2013, MSF conducted multiple household-based surveys in different areas of DRC, providing local information on vaccination coverage. Results of these surveys and their respective methodologies are reported elsewhere [12,13]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Although measles mortality has declined dramatically in Sub-Saharan Africa, measles remains a major public health problem in countries like the Democratic Republic of Congo (DRC). Here, we describe the large measles epidemic that occurred in the Democratic Republic of Congo between 2010 and 2013 using data from the national surveillance system as well as vaccine coverage surveys to provide a snapshot of the epidemiology of measles in DRC. Methods Standardized national surveillance data were used to describe measles cases from 2010 to 2013. Attack rates and case fatality ratios were calculated and the temporal and spatial evolution of the epidemic described. Data on laboratory confirmation and vaccination coverage surveys as a part of routine program monitoring are also presented. Findings Between week 1 of 2010 and week 45 of 2013, a total of 294,455 cases and 5,045 deaths were reported. The cumulative attack rate (AR) was 0.4%. The Case Fatality Ratio (CFR) was 1.7% among cases reported in health structures through national surveillance. A total of 186,178 cases (63%) were under 5 years old, representing an estimated AR of 1.4% in this age group. Following the first mass vaccination campaigns, weekly reported cases decreased by 21.5%. Results of post-vaccination campaign coverage surveys indicated sub-optimal (under 95%) vaccination coverage among children surveyed. Conclusions The data reported here highlight the need to seek additional means to reinforce routine immunization as well as ensure the timely implementation of Supplementary Immunization Activities to prevent large and repeated measles epidemics in DRC. Although reactive campaigns were conducted in response to the epidemic, strategies to ensure that children are vaccinated in the routine system remains the foundation of measles control.
    Full-text · Article · Jul 2014 · Conflict and Health
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In a highly interconnected world, immunizing infections are a transboundary problem, and their control and elimination require international cooperation and coordination. In the absence of a global or regional body that can impose a universal vaccination strategy, each individual country sets its own strategy. Mobility of populations across borders can promote free-riding, because a country can benefit from the vaccination efforts of its neighbours, which can result in vaccination coverage lower than the global optimum. Here we explore whether voluntary coalitions that reward countries that join by cooperatively increasing vaccination coverage can solve this problem. We use dynamic epidemiological models embedded in a game-theoretic framework in order to identify conditions in which coalitions are self-enforcing and therefore stable, and thus successful at promoting a cooperative vaccination strategy. We find that countries can achieve significantly greater vaccination coverage at a lower cost by forming coalitions than when acting independently, provided a coalition has the tools to deter free-riding. Furthermore, when economically or epidemiologically asymmetric countries form coalitions, realized coverage is regionally more consistent than in the absence of coalitions.
    Full-text · Article · Jan 2016 · Journal of The Royal Society Interface