Title : Beyond coverage estimates: Leveraging analytical approaches from Cameroon’s Multiple Indicators Cluster Survey (MICS) to strengthen future immunization planning
Abstract:
Background: In Cameroon, vaccination coverage remains below national and global targets, partly due to missed opportunities for vaccination (MOV) and delays in timely immunization. While household surveys such as the Multiple Indicator Cluster Survey (MICS) provide valuable data, older ones can be used to develop statistical analysis plans that can be applied to more recent or future datasets. This study uses the MICS 2014 dataset to explore MOV and vaccination timeliness, not to inform present-day vaccination strategies directly, but to propose an analytical framework that can be reused in future surveys to better interpret vaccination data and guide targeted improvements in immunization services.
Methods: Children aged 12–35 months with documented vaccination histories (from cards) were included. MOV was defined as the failure to receive eligible vaccine doses during health system contacts, identified using recorded vaccination dates in relation to visit history, and simultaneously estimated with all the antigens involved. Vaccination timeliness based on the national immunization schedule, with doses classified as early, timely, or delayed. Timeliness-to-completeness identifies how many children were protected on time. MOV descriptive statistics and disaggregated analyses by different MICS variables, and decision tree for a call to action.
Results: A total of 2214 alive children aged 12 to 35 months were surveyed, and 1447 (65.3%) had cards seen with dates. A percentage of 66.3 of children were completely vaccinated. Vaccination timeliness was all below 80% and ranged from 34.7% for BCG to 61% for Penta1 and PCV1. Timely and completeness for dose specific ranged from the lowest of 27%for BCG, 50% for Polio 3, 52% for MCV1, 46.1% for Penta3, and 48.1 for the Yellow Fever vaccine. The national prevalence of MOV for simultaneous vaccines was 90%; 95% confidence interval (CI)=84%-94%. Within this prevalence, 61% (95% CI=53-69) had previous missed vaccines uncaught. MOV was an issue in all regions and more prevalent in rural areas that urban areas. MOV was more prevalent for yellow fever. Significant differences between proportions of MOV were found for place of residence, mother’s education, wealth index, prenatal consultation, vitamin A contact, domestic violence, religion, and the number of vaccination contact. Dose specific MOV ranged from the lowest of 4% (56/1413) for BCG, to the highest of 53.04% for the yellow fever, to 57.1% for polio vaccines. Significant interactions between boys and girls were found. Decision tree revealed the importance of attaining all scheduled visits to reduce the risk of uncaught vaccines.
Conclusion: Although this work provides results from a distant past, it highlights a methodology for survey data analysis and demonstrates how findings can be obtained on both vaccination timeliness and combined timeliness and completeness, along with missed opportunities for vaccination (MOV). It also identifies research topics to explore, suggesting that such an approach should be considered in the conduct of future surveys.
Keywords: timeliness, MICS, analytics and insights, domestic violence, vaccination timeliness, MOV, children, health system performance, Cameroon
