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Waning immunity, prevailing non-vaccine type ptxP3 and macrolide-resistant strains in the 2024 pertussis outbreak in China: a multicentre cross-sectional descriptive study

Jiehao Cai, Qiyi Liu, Bi-Quan Chen, Yue Jiang, Xiaoyan Zeng, Jiebin Huang, Daojiong Lin, Huanyou Li et al.

The Lancet Regional Health - Western Pacific, 2025

23 citations

Abstract

Summary Background In the spring and summer of 2024, an unexpected large outbreak of pertussis hit China, with the annual incidence of pertussis (34.03/100,000) more than 12-fold higher than that of 2023 (2.71/100,000). We aimed to assess clinical and molecular epidemiological patterns and unravel the reasons behind the 2024 pertussis outbreak. Methods PCR-confirmed pertussis cases were enrolled from five sentinel hospitals in Shanghai, Anhui, Hainan, Fujian, and Inner Mongolia between 1 January and 30 September 2024. The epidemiological data of PCR-confirmed cases, as well as the clinical data and vaccination history of hospitalized cases were collected. Nasopharyngeal swab samples were collected from partial pertussis cases and their household contacts for Bordetella pertussis culture during the local peak months. Antimicrobial susceptibility testing and whole genome sequencing were performed on all 394 isolates to evaluate six antibiotic susceptibility and characterize the antigenic, virulent, and phylogenetic characteristics of the circulating isolates. Findings A total of 14,874 cases of pertussis were PCR-confirmed in the 5 sentinel hospitals, peaking in April to July. Infants represented 9.6% of cases and children aged 4–10 years represented 74.3% of cases in the five hospitals. Of the 7238 (48.7%) cases with vaccination data, 6563 (90.7%) were fully vaccinated. Breakthrough pertussis cases were mainly observed in fully vaccinated children since the age of 7 months.…

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Evidence Hub reads this as a cross-sectional, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause.

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