Effectiveness of the Booster of SARS-CoV-2 Vaccine among Japanese Adolescents: A Cohort Study

Yoshika Saito; Kana Yamamoto; Morihito Takita; Masahiro Kami; Masaharu Tsubokura; Kenji Shibuya

doi:10.3390/vaccines10111914

Effectiveness of the Booster of SARS-CoV-2 Vaccine among Japanese Adolescents: A Cohort Study

Vaccines (Basel). 2022 Nov 12;10(11):1914. doi: 10.3390/vaccines10111914.

Authors

Yoshika Saito¹, Kana Yamamoto^{1

2}, Morihito Takita^{1

2}, Masahiro Kami^{1

3}, Masaharu Tsubokura^{2

3

4}, Kenji Shibuya^{3

4}

Affiliations

¹ Research Division, Medical Governance Research Institute, 2-12-13-201 Takanawa, Tokyo 108-0074, Japan.
² Department of Radiation Health Management, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1247, Japan.
³ Soma COVID Vaccination Medical Center, 63-3 Nakamura-Kitamachi, Soma 976-8601, Japan.
⁴ Tokyo Foundation for Policy Research, 3-2-1 Roppongi, Tokyo 106-6234, Japan.

Abstract

Vaccination is effective in preventing COVID-19-related hospitalization among all age groups, but there is limited evidence on the effectiveness of the booster of the SARS-CoV-2 vaccine among adolescents. We analyzed the data on the status of SARS-CoV-2 infection and their vaccination profiles in adolescents aged 13-18 years in Soma city (Fukushima, Japan) (n = 1835) from 14 May to 15 June 2022. The crude incidence rate and 95% confidence interval were calculated with the negative-binomial regression model after classifying the immunization status. The crude effectiveness of a booster administration to prevent infections was estimated as 86.4% (95% confidence interval: 57.2-95.7) when compared with the primary vaccination alone. The results of this study support that the community-based mass vaccination campaign of a booster dose among adolescents has additional protection from COVID-19 during the period of the B.1.1.529 (omicron) variant wave.

Keywords: COVID-19; adolescent; booster; infection; vaccination.

Grants and funding

This study is supported in part by a grant of the collaborative studies for radiation disasters and medical science in the Fukushima Medical University, entitled ‘The long-term health survey for the adolescents evacuated after the Great East Japan Earthquake’ (Fukushima, Japan).