Objective  To understand the epidemiological characteristics and incidence trend of pertussis in Hainan province from 2018 to 2024, and provide critical evidence for the improvement of pertussis prevention and control strategies.

Methods The incidence data of pertussis in Hainan from 2018 to 2024 were collected from the Infectious Disease Reporting Management Information System for a descriptive epidemiological analysis to describe the spatial, time and population distributions of the pertussis cases. The annual average growth rate was calculated by using the compound annual growth rate, and analyze the seasonality of pertussis were analyzed by using concentration and circular distribution methods. The data were processed and the epidemiological characteristics were analyzed by using WPS, the incidence trends and average annual percentage change (AAPC) analyzed by using software Joinpoint, and regional incidence clustering analysis was conducted by using software R version 4.4.1.

Results From 2018 to 2024, a total of 3 435 pertussis cases were reported in Hainan, with an average annual incidence of 4.98/100 000 and an average annual growth rate of 105.29%. The concentration analysis showed that the disease incidence showed seasonality in some years, and the circular distribution method suggested that the high incidence could occur all the year round. The area distribution of the cases was uneven, with Haikou reporting 1 180 cases, accounting for 71.30% of of the cases reported in top 5 areas with high incidences in the province; Cluster analysis divided the pertussis incidence in 18 counties (city) into 5 levels, with Changjiang, Haikou and Chengmai being the high incidence areas. The average annual incidence rate was higher in men (5.24/100 000) than in women (4.68/100 000)(χ²＝10.874, P<0.001). The cases were mainly distributed in the age group 5−<10 years (42.56%) with the average annual incidence rate of 29.82/100 000 and the age group 0−<1 year (34.41%) with the average annual incidence rate of 171.43/100 000. In the age group 0−<1 year, the pertussis cases in those aged 1 month increased significantly compared with those aged <1 month, and the incidence peaked in age group at 3 months (224 cases, 18.95%). Joinpoint regression analysis showed that the incidence in age group0−<1 year, 5−<10 years, 10−<15 years and 15− years showed significant increases (AAPC: 127.03% in the 5−<10 year old group and 119.93% in the 10−<15 year old group). The cases were mainly home-cared children (47.28%), followed by children in child care settings (26.87%) and students (24.80%).

Conclusion From 2018 to 2024, the incidence of pertussis showed a fluctuating upward trend in Hainan, with uneven area distribution, and the cases were mainly young children and students. It is suggested to strengthen the surveillance in key areas and key populations and improve pertussis prevention and control strategies.