TY - JOUR
T1 - Effectiveness of four doses of pertussis vaccine during infancy diminished in elementary school age
T2 - A test-negative case-control study in Japan
AU - Ohfuji, Satoko
AU - Okada, Kenji
AU - Mouri, Yoko
AU - Mihara, Yuka
AU - Ishii, Shigeki
AU - Miyata, Akiko
AU - Fujino, Motoko
AU - Motomura, Chikako
AU - Ito, Hiroaki
AU - Ohta, Mitsuhiro
AU - Kasahara, Yoshihito
AU - Nakamura, Hideo
AU - Hasui, Masaki
AU - Yoshikawa, Tetsushi
AU - Tanaka, Takaaki
AU - Nakano, Takashi
AU - Koshida, Rie
AU - Araki, Kaoru
AU - Hara, Megumi
AU - Hirota, Yoshio
N1 - Publisher Copyright:
© 2020 The Author(s)
PY - 2021/1/3
Y1 - 2021/1/3
N2 - 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.
AB - 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.
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U2 - 10.1016/j.vaccine.2020.11.035
DO - 10.1016/j.vaccine.2020.11.035
M3 - Article
C2 - 33229109
AN - SCOPUS:85096568148
SN - 0264-410X
VL - 39
SP - 11
EP - 17
JO - Vaccine
JF - Vaccine
IS - 1
ER -