Impact of COVID-19 vaccination by implementation timing and coverage rate in relation to misinformation prevalence in Japan.

Vaccine [Vaccine] 2025 Jun 20; Vol. 59, pp. 127273. Date of Electronic Publication: 2025 May 20.

Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yuki Furuse reports financial support was provided by Japan Agency for Medical Research and Development. Yuki Furuse reports financial support was provided by Japan Society for the Promotion of Science. Takahiro Tabuchi reports financial support was provided by Japan Society for the Promotion of Science. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
COVID-19 vaccines have saved many lives during the pandemic. However, the implementation strategy of vaccination in some countries may not have been ideal. In this study, we investigated the impact of vaccination on COVID-19 mortality in counterfactual scenarios for different vaccine implementation timings and coverage in Japan. To do so, we developed a mathematical model to predict the number of COVID-19 deaths using weekly data on COVID-19 cases, vaccination coverage, vaccine effectiveness, and the proportion of SARS-CoV-2 variants. We also reanalyzed survey data from our previous study about the prevalence of misinformation beliefs and attitudes toward COVID-19 vaccination, in order to build counterfactual scenarios in which we had managed misinformation better or worse. In Japan, the COVID-19 death toll was 14,994 in 2021 before the emergence of the Omicron variant in December. Counterfactual scenario simulations using the mathematical model revealed that 30,117 deaths were averted by vaccination in 2021, considering the direct and indirect effects of vaccines. If we had failed to manage the influence of misinformation, vaccination coverage would have dropped from 83.4 % to 76.6 %. And there would have been 1020 more deaths. The death toll could have decreased by 431 in a scenario for better misinformation management, assuming vaccination coverage of 88.0 %. Three-month delayed vaccination implementation would have increased the death toll by 22,216, whereas three-month early implementation would have averted 7003 deaths. Therefore, implementation timing had a stronger effect than vaccination coverage. This study highlights the importance of assessing vaccination strategies from the perspective of misinformation management and timing to start vaccination rollout.
(Copyright © 2025 The Authors. Published by Elsevier Ltd.. All rights reserved.)

English

Publisher: Elsevier Science Country of Publication: Netherlands NLM ID: 8406899 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1873-2518 (Electronic) Linking ISSN: 0264410X NLM ISO Abbreviation: Vaccine Subsets: MEDLINE

COVID-19*/prevention & control , COVID-19*/mortality , COVID-19*/epidemiology , COVID-19 Vaccines*/administration & dosage , COVID-19 Vaccines*/immunology , Vaccination Coverage*/statistics & numerical data , Communication* , Vaccination*/statistics & numerical data, Humans ; Japan/epidemiology ; SARS-CoV-2/immunology ; Models, Theoretical ; Vaccine Efficacy ; Health Knowledge, Attitudes, Practice ; Prevalence

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