Epidemiological and Clinical Characteristics of Measles in Jinan, Shandong Province, China, from 1991 to 2022.

Objective: This study aimed to analyze the epidemiological and clinical characteristics of measles in Jinan, Shandong, China, over a 32-year stage to facilitate measles prevention in the future. Methods: Data on measles cases from 1991 to 2022 were obtained from the public health department and medical records of patients at Shandong Public Health Clinical Center. Retrospective analysis was conducted on the distribution of measles cases in different years, months, and age groups, and observation of the differences in clinical manifestations and complications among different age groups. Results: From January 1991 to December 2022, 7531 measles cases were recorded at Shandong Public Health Clinical Center. During the 32-year period, there were two outbreaks of measles in 2008 and 2016, respectively. During the COVID-19 pandemic period from 2020 to 2022, the number of cases reached the lowest point in the past 30 years. The number and percentage of cases in the 0-1y groups was significantly higher than in other age groups, and 97.75% patients in this group did not receive measles vaccine. Complications such as pneumonia and myocarditis appeared more frequent in patients under 12 years of age, but liver function damage is more common in adult patients. Conclusion: Although the measles epidemic has been greatly controlled since the use of measles vaccine, intermittent outbreaks still exist, so there is still a long way to go to eliminate measles. The proportion of infants under the age of 1 without measles vaccine and adults over 24 years old accounts for nearly 80% of the total. This group of people should be of concern, and feasible measures should be designated to protect these susceptible populations.