Maternal Vitamin D Status Affects Hepatitis B Vaccine Response in Breastfeeding Infants

Abstract

Background/Hypothesis: Vit D affects immune function across the lifespan, which includes pregnancy and lactation. We hypothesized that the response of fully breastfeeding infants to HBV would differ as a function of both maternal and infant's vit D status as measured by circulating 25(OH)D concentration. Method(s): Circulating 25(OH)D concentration and HBV titers were measured in a subset of mothers and infants (n = 20) participating in a lactation vit D supplementation clinical trial. Mothers were randomized to receive either 400 vs. 6400 IU vitamin D3/day and infants 400 IU/day or placebo (if mother was in 6400 IU group). 25(OH)D concentration (RIA) and infant anti‐HBV IgG titers (ELISA) at 4 and 7 months of age (n = 20 each) were measured. The association between maternal vit D treatment group, circulating 25(OH)D, and HBV IgG titers was explored using Spearman's correlation and ANOVA. Result(s): Infants of mothers in 6400 IU group had similar titers compared to 400 IU control infants at 4‐months of age, but titers decreased significantly by 7‐months (p < 0.001). Group A, infants directly‐supplemented 400 IU vitamin D/day (mothers supplemented with 400 IU vitamin D/d); Group B, mothers only supplemented 6400 IU vitamin D/d (n = 20/group). Conclusion(s): HBV titers of fully breastfeeding infants differed at 7 months of age by maternal vi tD treatment and not on the basis of infant vit D status. These findings suggest that the regulation of infant immune response to maternal signals differentially through her breast milk on the basis of maternal vit D status.