Genetic Characterization of Mumps Viruses Associated with the Resurgence of Mumps in the United States: 2015-2017.

•From 2015–2017 greater than 13,800 cases of mumps were reported in the United States.•In 2013, the CDC and the Association of Public Health Laboratories contracted four Vaccine Preventable Diseases Reference Centers (VPD-RCs) to perform real-time reverse transcription PCR (RT-qPCR) to detect mumps RNA in clinical samples and to determine the genotype.•Phylogenetic analysis of the 1862 mumps samples genotyped from 2015 through 2017 showed that the overall diversity of genotypes detected was lo. Most sequences (98.7 %) were genotype G.•Within genotype G, a small number of phylogenetically significant outlier sequences were associated with epidemiologically distinct chains of transmission.