Measles and Rubella Seroprevalence in Mother–Infant Pairs in Rural Nepal and the United States: Pre- and Post-Elimination Populations

We sought to compare seroprevalence of protective measles and rubella-specific antibody in mother–infant pairs across two populations: a pre-disease elimination Nepal population with recently introduced rubella vaccine and post-disease elimination U.S. population. Qualitative measles and rubella immunoglobulin G was assessed in maternal serum and cord blood from 258 pairs in Nepal, 2012–2013 and 49 pairs in Seattle, WA, 2014–2015. High rates of protective antibody were observed in both populations. Two hundred and forty-four (95%) pregnant women in Nepal had protective measles antibody versus 44 (92%) in Seattle (P = 0.42). Ninety-six percent of infants in Nepal (N = 246) and Seattle (N = 43) had protective measles antibody (P = 0.75). Ninety-four percentage of pregnant women in Nepal (N = 242) and Seattle (N = 45) had protective rubella antibody (P = 0.23). Two hundred and thirty-eight (93%) infants in Nepal had protective rubella antibody versus 44 (98%) in Seattle (P = 0.12). Continued surveillance will be necessary to ensure protective immunity, inform progress toward disease elimination in Nepal and avoid reemergence in the United States.