Oral rotavirus vaccine effectiveness among malnourished children in 19 countries: Findings from the MNSSTER-V project

Objectives: Rotavirus vaccine clinical trials and post-licensure evaluations found malnourished children may have lower protection against rotavirus diarrhea hospitalizations than well-nourished children. On a population level, rotavirus vaccines are less protective in high child mortality settings. Methods: We analyzed rotavirus vaccine effectiveness (VE) among malnourished and well-nourished children categorized using four anthropometric malnutrition indicators, birthweight, and reported malnutrition from medium to high child mortality countries in the Multi-National Subpopulations Study to Evaluate Rotavirus Vaccines (MNSSTER-V) dataset. We calculated child-level z-scores for weight-for-age, length-for-age, weight-for-length, and mid-upper arm circumference (MUAC), and the site-level proportion implausible z-scores. Sites with published VE estimates by nutritional status or those with <3% implausible values were included in the final analysis. Z-scores <−2 were considered moderate-to-severe malnutrition and <−3 were considered severe malnutrition. We calculated complete series rotavirus VE in each malnourished and well-nourished group using an unconditional adjusted logistic regression model, where VE = (1 − odds ratio of vaccination among cases and controls) × 100, where cases and controls were children who tested rotavirus positive and negative, respectively. Results: Complete series VE was more protective among children without stunting (normal length-for-age) (59%; 95% confidence interval [CI]: 49–67) compared to children with moderate-to-severe stunting (42%; 95% CI: 19–58) and severe stunting (31%; 95%CI: −14 to 58). Adjusted VE point estimates were similar among malnourished and well-nourished children using the other anthropometric and birthweight indicators. Conclusions: Our findings clearly show that chronic malnutrition negatively impacted rotavirus VE. Efforts to address and prevent malnutrition generally may further reduce the burden of rotavirus morbidity and mortality.