Measles-vaccinated children found to have significantly higher HAZ (Height for age) scores in India, BMIZ (BMI-for-age) and WAZ (weight-for-age) scores in Vietnam compared with matched measles-unvaccinated children, according to a new study done across three countries.
According to the US Centers for Disease Control and Prevention (CDC), there have been over 1,000 measles cases reported across 28 states in the US so far in 2019. This is the largest number of cases the country has seen in almost 3 decades, and since measles was eliminated in 2000. Despite these recent setbacks, the highly efficacious and cost-effective measles vaccine prevented an estimated 21.1 million child deaths worldwide between 2000-2017.
While the measles vaccine has eliminated the virus in many high-income countries, the global burden of disease persists with an estimated 245,000 measles cases and 68,000 measles-associated deaths worldwide in 2016. India alone accounted for 50 percent of measles cases and 30 percent of measles deaths in 2016. Although low- and middle-income countries (LMICs) account for a large proportion of global measles cases, high-income countries have recently seen a resurgence of measles outbreaks.
The vaccine has also been tied to reductions in all-cause childhood mortality and infectious disease morbidity outcomes in LMICs, although little generalizable evidence exists on the early-life receipt of measles vaccines and associated child growth parameters, cognition, and schooling grades.
Researchers examined Z- scores of HAZ, BMIZ, WAZ, scores of Peabody Picture Vocabulary Test (PPVT), early grade reading assessment (EGRA), language and mathematics tests, and highest schooling attainment across ~6,000 measles-vaccinated and unvaccinated children in Ethiopia, India, and Vietnam. Propensity score matching methods were used to reduce the effects of potential confounding factors.
Researchers analyzed survey data from 3 cohorts of children enrolled in the Young Lives Survey (YLS), a longitudinal study assessing childhood poverty. Growth, cognitive, and schooling indicators were evaluated across measles-vaccination groups, and outcomes at ages 7-8 and 11-12 years were compared between children across the 3 countries with reported receipt or non-receipt of measles vaccination at 6-18 months of life.
“We reviewed children who were followed since infancy through childhood and used statistical techniques that produced robust estimates of the associations of measles vaccination with later life outcomes. It is the first and the largest multi-country study of its kind.”, said CDDEP senior fellow Arindam Nandi, the lead author of the study.