Japan's immunization program resumed proactively recommending the use of the human papillomavirus (HPV) vaccine nationwide in April 2022, after suspending this recommendation in June 2013. The promotion of catch-up vaccinations is an urgent issue to reduce the increase in cervical cancer and other cancers caused by low vaccination rates. In addition, the National Immunization Program still has issues to be considered, such as the adoption of the 9-valent vaccine, establishment of an appropriate number of vaccinations according to age, and routine immunization of males. There is a history of eliminating the use of the measles, mumps, and rubella vaccine and the mouse brain-derived, purified inactivated Japanese encephalitis vaccine, as well as suspending the HPV vaccine recommendation in Japan. These decisions have led to the current preventable infectious disease burden. In order to make the right policy decisions based on science-based assessments, it is necessary to establish a safety assessment platform to evaluate the causal relationship between vaccines and adverse events following immunization. Information technology, which has been promoted with the coronavirus disease 2019 vaccine in the current pandemic, may assist in providing more detailed vaccine safety evaluations for other vaccines.