In settings where vitamin A deficiency is a public health problem, the World Health Organization (WHO) recommends a high-dose vitamin A supplement every six months for children 6–59 months to reduce child morbidity and mortality. The recommended dose for children 6–11 months is 100 000 International Units (IU), and for children 12–59 months, it is 200 000 IU. Because vitamin A is fat soluble, the liver can effectively absorb and store a high dose of vitamin A and use it over an extended period of time. High-dose vitamin A supplementation improves vitamin A status for up to three months only in children who have low dietary intake. It is insufficient for preventing vitamin A deficiency because it does not address the underlying cause of the deficiency4.
Many countries have integrated universal distribution of high-dose vitamin A supplementation into campaign events—such as child health or immunization days—while others are beginning to use routine fixed facility and outreach health services. When high-dose vitamin A supplementation is available through multiple channels (i.e., campaigns and routine services), tracking receipt becomes an important activity to minimize the risk of providing too many doses to young children within a short time span (Klemm et al. 2016).
Measurement and data sources
Population-based surveys typically report the percentage of children 6–59 months who were given vitamin A supplementation in the six months preceding the survey. In post-event coverage surveys, coverage is the percentage of the eligible population that received vitamin A supplementation during the last campaign. These surveys usually take place within a few weeks of the campaign. The target coverage for an effective high-dose vitamin A supplementation program provided through immunization programs is at least 90 percent in 80 percent of districts to achieve mortality reduction (WHO 2013).
Surveys that collect information related to high-dose vitamin A supplementation coverage include—
- Demographic and Health Surveys
- Multiple Indicator Cluster Surveys
- National Micronutrient Surveys
- post-event coverage surveys
- Knowledge, Practice, and Coverage Surveys
- other research or evaluation activities.
In addition, health monitoring information systems may include coverage estimates of vitamin A supplementation—both from mass treatment events, as well as routine treatment. For campaign-based distribution, these data often come from tally sheets completed at the time of mass supplementation, which are compared against the total target population to obtain coverage estimates. In this context, high-dose vitamin A supplementation coverage refers to the percentage of children who received an age-appropriate dose of vitamin A within a semester and within both semesters in a year (semester 1 is usually January–June; semester 2 is usually July–December).
Administrative data are sometimes accessible through the Expanded Programme on Immunization, Ministry of Health nutrition units, or donors of the high-dose vitamin A supplementation program (e.g., Helen Keller International, Micronutrient Initiative, and UNICEF).
- Generally, tally sheets and other administrative data may overestimate vitamin A supplementation coverage compared to post-event coverage survey data, so it is preferable to use post-event coverage data.
- Recall bias in routine population-based surveys may result in lower coverage estimates compared to post-event surveys. For instance, vitamin A supplementation coverage from Demographic and Health Surveys usually underestimates true coverage, because the timing of the survey in relation to the vitamin A supplementation distribution impacts maternal recall (Hodges et al. 2013; Dhillon et al. 2013).
- Consider the regularity of high-dose vitamin A supplementation campaigns, as well as the timing of data collection, in relation to a deworming campaign. Discrepancies may be noted between different data sources, based on whether information was collected prior to or following a supplementation campaign. In other words, coverage estimates from Demographic and Health Surveys, Multiple Indicator Cluster Surveys, or National Micronutrient Surveys may be affected by the time interval between the survey and the mass supplementation, especially when estimates are compared between years.