# Epidemiological Characteristics of Mumps Under Different Immunization Strategies in Henan Province

## TL;DR

This study shows that a 2-dose mumps vaccine strategy in Henan Province significantly reduced mumps cases and highlights the need for continued vigilance in older populations.

## Contribution

The study evaluates the impact of a 2-dose mumps vaccine strategy on incidence rates in Henan Province, providing insights into its effectiveness and seasonality patterns.

## Key findings

- The average annual mumps incidence decreased by 60.29% after implementing the 2-dose vaccination strategy.
- Mumps incidence peaks were observed from April to July and December to January, with less pronounced seasonality after 2019.
- The proportion of cases in individuals over 20 years old increased from 8.17% to 15.55% between 2004–2008 and 2019–2024.

## Abstract

Background: On 1 January 2019, a 2-dose mumps-containing vaccine (MuCV) immunization strategy was adopted in Henan Province before the national Expanded Program on Immunization (EPI). This study examines the epidemiological characteristics of mumps cases during the implementation of various immunization strategies in Henan Province. Methods: We employed descriptive statistics and initially retrieved data on reported cases from 2004 to 2024. Mumps case data were sourced from the China Information System for Disease Control and Prevention (CISDCP). Results: Between 2004 and 2024, a total of 301,342 cases of mumps disease were reported in Henan Province, and the average annual reported incidence was 15.11 cases per 100,000 people. The average yearly incidence decreased by 60.29% following the implementation of the 2-dose vaccination strategy compared with the one-dose strategy. The study identifies two annual incidence peaks from 2004 to 2024: a prominent peak from April to July and a smaller peak from December to January. From 2019 to 2024, in addition to a slight dip in February, the seasonality was less pronounced, with cases distributed sporadically throughout the year. The proportion of the population over 20 years old increased annually, from 8.17% in 2004–2008 to 15.55% in 2019–2024. There was an overall negative correlation between the estimated MuCV vaccination rate and the reported incidence of mumps (r = −0.685, p < 0.05). Conclusions: The introduction of 2-dose MuCV in the EPI significantly reduced the incidence rate and total number of cases. While continuing the 2-dose MuCV immunization strategy in the future, it is crucial to remain vigilant in preventing and controlling mumps among individuals over 20 years old.