Abstract Importance Despite vaccinations reducing the global burden of pertussis, its resurgence poses a significant public health challenge. China expanded its pertussis immunization strategy in January 2025 by introducing a booster dose for 6-year-old children. It is therefore critical to investigate the current pertussis epidemiology and assess the immediate impact of this booster vaccination. Objective The primary objective was to investigate pertussis community-based epidemiology in China, with the secondary aim to evaluate the epidemiological impact of pertussis booster vaccinations. Design, Setting and Participants: A time-trend analysis was performed of pertussis cases reported through home-based surveillance platform from May 2024 to August 2025 in four cities (Beijing, Shanghai, Guangzhou and Shenzhen) of China. Main Outcome(s) and Measure(s): Detection rate and number of pertussis cases were calculated and compared were calculated and compared between different age groups and before/post implementation of booster vaccination strategy. Results A total of 3319 of 67238 (4.9%) were confirmed as pertussis from May 2024 to August 2025 across four surveillance cities in China. The outbreak peaked at over 300 biweekly cases during May and June 2024. Notably, 1759 (52.4%) pertussis cases occurred in school-aged children (Fig A). Genomic surveillance revealed ptxP3 strains dominated (95.2%, 60/63) (Table 1). Booster vaccination was associated with a reduction in the pertussis detection rate, ranging from 1.22% to 5.22% in the target age groups (Fig B). Conclusions and Relevance This study revealed a significant pertussis resurgence in China, characterized by a distinct shift in disease burden from preschool to school-age children. The predominance of hypervirulent ptxP3 strains likely contributes to this resurgence. The 6-year-old booster vaccination shows potentially protective effects for the high-risk school-age populations although continued surveillance is required to assess its impact in the medium to long term. These findings suggest that the needs for proactive implementation of updated immunization strategies to address shifting susceptibility populations. This abstract is funded by: National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No.2024ZD0522501)
Xiang et al. (Fri,) studied this question.