Objective To analyze the epidemiological and clinical characteristics of pertussis in Baoshan District, Shanghai from 2017 to 2024, so as to provide an evidence-based reference for optimizing prevention and control strategies.

Methods Data on pertussis cases were collected from the China Disease Prevention and Control Information System, Shanghai Integrated Management and Immunization Service Information System, and follow-up epidemiological investigations. Descriptive epidemiological analyses were performed to analyze the epidemiological characteristics, clinical manifestations, and vaccine effectiveness. Joinpoint regression analyses were used to examine the temporal trends in incidence rates, and a Poisson model was constructed for spatiotemporal scan analyses.

Results A total of 1 634 pertussis cases were reported in Baoshan District from 2017 to 2024, with a male-to-female ratio of 1.08∶1. More cases were observed in males than in females, with the age ranged from 20 days to 81 years. Among them, 59.92% were in the 6‒<11 years age group, and 63.34% were students. Low-level sporadic incidence persisted during 2017‒2023, followed by a sharp increase in 2024 (71.37/100 000). Starting in January 2024, the incidence rate showed an upward trend, peaking in May before declining. The majority of cases occurred between April and June. The trend in reported pertussis incidence rates in Baoshan District from 2017 to 2023 showed no statistically significant change (APC=10.039%, t=2.586, P=0.150). Incidence rate rose from January 2024, peaked in May (APC=133.641%, t=3.841, P=0.006), then declined significantly (APC=-47.816%, t=2.586, P<0.001). The 12 subdistricts of Baoshan District were divided into low, medium, and high population density areas, with an average annual reported incidence rate of 6.09/100 000, 8.19/100 000 and 11.96/100 000, respectively. The reported incidence rate increased with an increase in population density. Spatiotemporal scan analyses showed that cases clustered in the southwest and northeast of Baoshan District. Epidemiological follow-up investigations of 1 520 cases revealed that the main clinical symptoms were cough (97.63%) and sputum production (41.58%), and 98.13% of the cases were confirmed by positive nucleic-acid test results. Among the 1 475 cases with immunization records, 83.53% had completed the four-dose pertussis vaccine before onset. The complication incidence rates, from high to low, were in the 0-dose vaccination group, 1‒3-dose vaccination group and 4-dose vaccination group. The duration of cough, from long to short, was observed in the the 0-dose vaccination group, 1‒3-dose vaccination group and 4-dose vaccination group, correspondingly.

Conclusion It is recommended to improve the pertussis surveillance system in medical institutions and establish an active monitoring network, prioritizing deployment in school settings and areas with high population density. Enhancing diphtheria-tetanus-pertussis (DTP) vaccination coverage among 6-year-old children and further optimizing the pertussis immunization strategies are essential to prevent and reduce the risk of pertussis among school-aged children.