Epidemiological characteristics and survival analysis of pertussis in Quzhou.

Despite high vaccination coverage in high-income countries, recent reports of pertussis resurgence have heightened public concern about vaccine effectiveness and vaccination. Quzhou City has gradually transitioned from DTwP to DTaP vaccines, achieving a remarkable vaccination coverage rate of 99%. However, since 2024, there has been a significant surge in pertussis cases in Quzhou City. We collected data on pertussis cases, described the epidemiological characteristics of pertussis outbreaks in Quzhou City, examined pertussis vaccination history, and conducted a COX survival analysis. Pertussis cases reported in Quzhou City from January to April 2024 were far higher than those reported in previous years during the same period. Geographically, cases were concentrated in the central region and predominantly affected children under 9 years old, with a focus on the 5-9 age group. Survival analysis revealed that the risk of pertussis incidence increased by 2.84 times (HR = 2.87, 95% CI = 2.27 ~ 3.63) when comparing self-paid vaccines to free vaccines. The pertussis situation in Quzhou City remains critical, emphasizing the need for enhanced immunization strategies and further optimization of pertussis immunization protocols.