The influence of infant nutritional status on rotavirus vaccine immunity in Bolivia

Paulina Rebolledo, MD, MSc

Summary

BACKGROUND: While the introduction of oral rotavirus vaccines in 2006 has been a major breakthrough, they have been found to provide sub-optimal protection among children in resource-constrained settings, and the reason for this disparity is unclear.

GAP: RV oral vaccines are 30% less effective in low versus high-income settings with this difference most pronounced in the second year of life following vaccination, leading to concerns of waning immunity over time. Undernutrition has been found to be associated with poor immune response to certain oral vaccines, however there is limited data evaluating undernutrition and the immune response to RV vaccines.

HYPOTHESIS: Among infants with chronic undernutrition (or stunting), infection with RV following vaccination will lead to a decline (or waning) of RV-specific immune correlates of protection

METHODS: This is a longitudinal observational study of the effects of infant undernutrition and RV infection on the kinetics of RV vaccine-specific immunity through 18 months of age in a cohort of Bolivian children. The study population includes 360 mother-infant dyads participating in a parent study being conducted in El Alto, Bolivia, with available information on household socioeconomic status, maternal and infant clinical history, morbidity, maternal and infant anthropometry, micronutrient serum levels, infant sera for RV-specific antibodies and molecular detection of RV in fecal samples.

RESULTS: Pending

IMPACT: Study results will improve our understanding of sub-optimal RV vaccine performance in resource-limited settings and provide data to optimize RV vaccine efficacy and in turn improve the lives of vulnerable infants.