Abstract
The study objectives were to analyze the epidemiological characteristics of pertussis in Henan Province, China, and to evaluate the impact of pertussis vaccination strategy adjustments on population infection rates. A retrospective analysis was conducted on the reported pertussis cases in Henan Province from 2012 to 2024. The concentration of IgG antibodies against pertussis toxin (anti-PT IgG) was measured in 18,528 healthy individuals from 2022 to 2024. The positive rate (≥20 IU/mL) and median concentration (MC) were calculated, and the infection rate was estimated based on anti-PT IgG ≥ 40 IU/mL, using the susceptible-exposed-infectious-recovered-vaccinated (SEIRV) model to predict the effect of adding a pertussis booster dose at 6 years. The average annual incidence of pertussis in Henan Province from 2012 to 2024 was 2.21 per 100,000 population. The overall anti-PT IgG positivity rate was 16.42 %, and the MC was 4.66 IU/mL. The antibody concentration is influenced by age, gender, and vaccine type. The population that completed the full course of vaccination had the highest anti-PT IgG positive rate (17.81 %) and the highest MC (4.97 IU/mL). The population that vaccinated the diphtheria-tetanus-acellular pertussis-inactivated polio vaccine-haemophilus influenzae type b (DTaP-IPV/ Hib) had the highest MC (14.83 IU/mL). The total estimated infection rate of pertussis was 7,833.45 per 100,000, peaking in the 6-year age group (10,809.72 per 100,000). When the estimated coverage rate of the pertussis booster vaccination reaches 83.21 %, the infection rate could be decreased by 71.41 %. The incidence of pertussis in Henan Province has increased, and the infection rate is higher than anticipated. Booster immunization at age six can significantly lower the risk of infection.