Modelling studies to identify the indirect effects of vaccines and the optimal immunizaion policies

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K24159
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0908:Society medicine, nursing, and related fields
• Research Institution: Kyoto University (2020-2021); Hokkaido University (2019)
• Principal Investigator: Suzuki Ayako 京都大学, 医学研究科, 特定助教 (90849986)
• Project Period (FY): 2019-08-30 – 2022-03-31
• Keywords: 水痘 / 予防接種 / 新型コロナウイルス / 疫学 / 数理モデル

Outline of Final Research Achievements

In this research project, we examined the impact of the introduction of routine varicella vaccination and public health measures associated with the pandemic of COVID-19 on varicella epidemiological dynamics in Japan.
Since the routine varicella vaccination program was introduced in October 2014, the number of reported varicella cases decreased rapidly. However, this study showed that the number of susceptibels has increased especially in children older than 10 years old, suggesting the need for the supplementary vaccination to the unvaccinated birth cohorts in the future. Furthermore, the varicella vaccine is highly effective, and despite the decrease in the number of infected during the COVID-19 pandemic, the susceptible population has not increased. The result indicated that a large epidemic is unlikely to occur in the future, even after life goes back to normal as it was before the pandemic.

Free Research Field

社会医学

Academic Significance and Societal Importance of the Research Achievements

本研究の目的はワクチン接種政策、感染症対策への数理モデルの活用であり、特に水痘に着目し研究を実施した。２０１４年１０年に開始された水痘ワクチン定期接種化の効果について評価しワクチン未接種の世代への追加接種の必要性を検討した点や、新型コロナウイルス感染症に伴って実施されてきた公衆衛生対策が将来の水痘疫学動態に与える影響を検討して点で社会的意義がある研究である。また、水痘ワクチンの定期接種化による水痘感染年齢の上昇については以前より指摘されており、日本の疫学データを利用して定量的に示した点で学術的な意義も高いと考える。