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.