Effectiveness of four doses of pertussis vaccine during infancy diminished in elementary school age: A test-negative case-control study in Japan. Issue 1 (3rd January 2021)

• Record Type: Journal Article
• Authors: Ohfuji, Satoko; Okada, Kenji; Mouri, Yoko; Mihara, Yuka; Ishii, Shigeki; Miyata, Akiko; Fujino, Motoko; Motomura, Chikako; Ito, Hiroaki; Ohta, Mitsuhiro; Kasahara, Yoshihito; Nakamura, Hideo; Hasui, Masaki; Yoshikawa, Tetsushi; Tanaka, Takaaki; Nakano, Takashi; Koshida, Rie; Araki, Kaoru; Hara, Megumi; Hirota, Yoshio
• Is Part Of: Vaccine. Volume 39:Issue 1(2021)
• Page Start: 11
• Page End: 17
• Publication Date: 2021-01-03
• Subjects: Effectiveness -- Pertussis vaccine -- School-aged children -- Test-negative case-control study -- Japan; OR odds ratio -- VE vaccine effectiveness -- DTaP vaccines acellular pertussis vaccine combined with diphtheria-tetanus toxoids -- Tdap tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine -- PT-IgG IgG for pertussis toxin -- LAMP method loop-mediated isothermal amplification method -- CI confidence interval; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2020.11.035
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: A test-negative case-control study examined an effectiveness of pertussis vaccine. 4 doses of vaccine provided a high effectiveness in subjects under 6 years of age. Vaccine effectiveness declines with time passed since the fourth dose. 4 doses of pertussis vaccine have no preventive effect for school-aged children. Abstract: Objective: The Japanese national immunization program recommends that children receive 4 doses of acellular pertussis vaccine between 3 months and 2 years of age. Nevertheless, the number of pertussis cases is increasing in elementary school children aged 6–12 years. Therefore, a test-negative case-control study was conducted to assess the effectiveness of the pertussis vaccine program. Methods: Subjects included children aged ≥3 months who visited a collaborating hospital due to pertussis-specific cough between October 2017 and November 2019. All subjects underwent diagnostic tests for pertussis, and those diagnosed as positive were regarded as cases. Subjects diagnosed as pertussis-negative were classified as controls. Vaccination history was collected using a questionnaire administered to parents with reference to immunization records. Logistic regression models were employed to calculate the odds ratio (OR) and 95% confidence interval for laboratory-confirmed pertussis. Results: Of 187 recruited subjects (120 cases and 67 controls), questionnaire responses were obtained for 145 subjects (95 cases and 50 controls). Compared with unvaccinated subjects, the vaccine effectiveness (VE) of 4 doses was 70% among all subjects and reached to 90% with marginal significance among subjects under 6 years of age. However, among school-aged subjects, the VE was not suggestive of protection against pertussis (VE: 8%). For vaccinees given 4 doses, the OR for developing pertussis increased significantly with longer duration since the fourth dose (compared with <4.5 years, OR of 6.0–8.2 years = 5.74; OR of ≥8.3 years = 3.88; P for trend by duration < 0.01). Conclusion: Effectiveness of administering 4 doses of pertussis vaccine during infancy decreases with time passed since the fourth dose. This regimen does not protect school-aged children against pertussis.