Pertussis epidemiology and seroprevalence in Wujin District, Changzhou, China, 2024
摘要
China experienced its worst pertussis epidemic in 30 years during 2024, and Wujin District faced the same challenge. This study aims to investigate the epidemiological characteristics of pertussis and the immune status of the healthy population in Wujin District, Changzhou City.
MethodsThe study employed descriptive epidemiology for pertussis case analysis and a serological survey for population antibody assessment in Wujin District, 2024. The level of pertussis toxin (PT) IgG antibody was measured by the Enzyme-Linked Immunosorbent Assay (ELISA).
ResultsA total of 28 pertussis cases were reported in 2024 in Wujin District, with an incidence rate of 2.15 per 100,000 population. Although infants < 1 year had the peak incidence (84.02 per 100,000), the 5–9 year age group accounted for the largest proportion of cases (67.86%) with an incidence rate of 28.70 per 100,000. 521 participants were included in the serological survey. Anti-PT IgG levels were undetectable (< 5 IU/ml) in 49.52% of the participants. The overall positivity (≥ 20 IU/mL) rate and antibody concentration were 17.27% and 5.17 IU/mL, respectively. The antibody positive rate was highest in the 1.5–3 years age group (30.00%) and lowest in the 20–29 years age group (7.89%). The recent infection (≥ 80 IU/mL) rate was 2.11%, with the top two observed in the 6–9 years old group (7.69%) and the 10–14 years old group (5.88%). The seropositivity rates and antibody concentrations of vaccinated individuals were higher than those of unvaccinated subjects or those with unknown vaccination history (all P-values < 0.05).
ConclusionWujin District saw a striking predominance of pertussis cases in school-aged children (5–9 years) in 2024. The antibody levels against pertussis in the healthy population were generally low, especially among adolescents and adults, calling for reinforced active surveillance targeting these age groups.
Clinical trial numberNot applicable.