Development and application of a Japanese vaccine database for comparative assessments in the post-authorization phase: The Vaccine Effectiveness, Networking, and Universal Safety (VENUS) study.

BACKGROUND: Japan currently lacks a data platform that can support quantitative assessments of the causal relationships between vaccines and adverse events. This study describes the development and application of the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) Study to facilitate such assessments.

METHODS: A database was created by linking public insurance enrollees' claims data with vaccination records acquired from participating municipalities. To provide an overview of the study data, we produced descriptive statistics of sex, age, and vaccinations. We also conducted a pilot study using the database to assess influenza vaccine safety during the 2018/2019 season among older persons (≥65 years) residing in a single municipality.

RESULTS: Our database was created using data from approximately 1.12 million individuals in 7 municipalities between 2013 and 2020. The data during fiscal year 2018 included 853,016 individuals (male: 363,079, female: 489,937) with a median age of 70 years (interquartile range: 52-79). We obtained information on 17 vaccine types, including the pneumococcal vaccine and influenza vaccine. In the pilot study, we analyzed 48,723 vaccinated persons matched with 48,723 unvaccinated persons. The only adverse event that occurred in both groups was Bell's palsy, which had an adjusted incidence rate ratio of 1.21 (95 % confidence interval: 0.48-3.07).

CONCLUSIONS: The VENUS Study is Japan's first healthcare data platform that enables comparative assessments of vaccinated and unvaccinated persons in large samples covering all age groups. Efforts are underway to increase the number of participating municipalities and to generate evidence on vaccine effectiveness and safety.