Routine vaccination has proven to be highly effective in reducing the incidence of mumps. However, sporadic cases and/or mumps outbreaks do occur in children and adolescents younger than 15 years old, particularly among those 5-9 years old. To explore the characteristics of such outbreaks in Henan Province, clinical data of patients infected with MuV were collected, and the isolated MuV strains were phylogenetically analyzed. Of a total of 426 samples, MuV RNA targeting the small hydrophobic

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... ) gene was detected in 153 samples. MuV-positive cases in each age group (< 5, 5-9,10-15, 16-19, and ≥ 20) accounted for 1%, 17%, 12%, 2% and 4% of the total number of cases, respectively. Phylogenetic analysis based on the SH gene sequences indicated that all of the isolated strains were of genotype F and isolates in the the same subcluster and identical SH gene sequences tended to be derived from the same community or municipalities when analyzed alongside epidemiological data. In conclusion, the incidence of mumps in Henan Province is high. The data provided in this study might promote further research in the clarification of specific cause of mumps outbreaks and which will facilitate the implementation of effective prevention and control measures.