Abstract:
Objective To evaluate the vaccine effectiveness (VE) of the adsorbed acellular diphtheria-tetanus-pertussis (DTaP) vaccine in infants and young children aged 2 years and under in Gansu province, thereby providing evidence for optimizing the immunization strategies for pertussis in underdeveloped western regions of China.
Methods A retrospective cohort was established, including 176 688 resident children born in Gansu province from January 1 to December 31, 2023. The Poisson regression model was adopted to calculate the relative risk (RR) for evaluating the VE of 1–4 doses of DTaP vaccine against pertussis and pertussis-related hospitalization, after adjusting for factors such as region and sex.
Results The coverage rates of the 1st to 4th doses of DTaP vaccine among infants and young children aged 2 years and under in Gansu province were 92.88%, 91.15%, 89.22%, and 41.96%, respectively. The VE of the 1st to 4th doses against pertussis was 43.67% (95%CI: 39.60%–55.21%), 71.30% (95%CI: 50.13%–79.96%), 90.91% (95%CI: 88.82%–92.68%), and 99.20% (95%CI: 77.91%–99.80%), respectively. The VE of the 1st to 4th doses against pertussis-related hospitalization was 56.14% (95%CI: 18.13%–77.80%), 63.90% (95%CI: 22.71%–85.46%), 73.02% (95%CI: 58.10%–82.34%), and 94.40% (95%CI: 64.32%–98.70%), respectively.
Conclusions The DTaP vaccine provides significant protection against pertussis and pertussis-related hospitalization in infants and young children aged 2 years and under in Gansu province in a dose-dependent manner. Efforts should focus on improving the timeliness of primary immunization and the coverage of booster doses.
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