June 20, 2019
The Question: 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.
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. 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.
What We Found: Researchers examined Z-scores of height-for-age (HAZ), BMI-for-age (BMIZ), weight-for-age (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.
The study found that at ages 7-8 years, measles-vaccinated children had significantly higher HAZ scores in India (an increase of 0.13 points, P=0.05), and significantly higher BMIZ and WAZscores in Vietnam (an increase of 0.18 and 0.23 points, P=0.04, 0.01 ) as compared with matched measles-unvaccinated children. Measles-vaccinated children scored 2.3, 2.5, and 2.7 points more on EGRA in Ethiopia, India, and Vietnam, respectively. Vaccinated children scored 4.5 and 2.6 percentage points (pp) higher on PPVT and 2.9 and 4.0 pp higher on mathematics in Ethiopia and Vietnam. Vaccinated children also attained 0.2-0.3 higher schooling grades across all ages and countries compared to measles-unvaccinated children.
Why It Matters: Findings indicate that measles vaccination at 6-18 months of life is associated with long-term health, cognition, and schooling benefits among children in Ethiopia, India, and Vietnam.
CDDEP director Ramanan Laxminarayan, a coauthor of the study, said, “At a time when there is hesitation about measles vaccination by parents, the results of this study are an important reminder that the benefits of measles vaccination go beyond child survival and are instrumental in enabling adults who have higher cognitive ability, education and physical stature. These are critical to economic development that every country aspires to.”
The study titled, “Anthropometric, cognitive, and schooling benefits of measles vaccination: longitudinal cohort analysis in Ethiopia, India, and Vietnam,” was published on June 18, 2019 in Vaccine.
