Epidemiological characteristics of measles in Baoshan District of Shanghai in 2005‒2021

Objective To determine the epidemiological characteristics and distributions of measles in Baoshan District， Shanghai.

Methods This study used the measles surveillance information and reporting system to collect reported cases of measles in Baoshan District in 2005‒2021 and then conducted descriptive epidemiological methods to determine the temporality using the concentration method.

Results In 2005‒2021， a total of 525 measles cases were reported in Baoshan District with an average annual reported incidence rate of 1.75/10⁵， showing an overall fluctuating downward trend and obvious seasonality. The cases concentrated in 30‒39 years of age （31.24%）， 20‒29 years （28.57%）， and under 5 years （16.57%）. Majority of them were workers （18.10%）， preschool children （16.19%）， and unemployed persons （12.76%）. The incidence was significantly higher in the central region than in the other two regions for workers， preschool children， and unemployed persons （χ²=54.515， P<0.001）. Spatially， the incidence was significantly higher in the north-central sub-districts than in the south （χ²=88.103， P<0.001）. Moreover， 33.14% of measles cases did not receive measles-containing vaccine （MCV）， while 53.90% of the cases remained unknown. Additionally， uptake rate of MCV in non-local residents was significantly lower than in local residents （χ²=14.422， P<0.001）.

Conclusion The measles incidence remains remarkably low in Baoshan District of Shanghai. Young and middle-aged populations in the north-central region are susceptible to measles. It is recommended to further strengthen measles surveillance， maintain high coverage of MCV among school-age children combined with catch-up immunization for at-risk populations， and improve health education.