Influenza vaccination coverage in Chiburijima Island, Japan: Impact of diversification of vaccination place.

Influenza vaccination rate in Chiburijima Island increased by 20% between 2007 and 2017, although the rate among the elderly Japanese people decreased by 4% based on the national data of routine immunization. Shortening the distance to vaccination places might improve the coverage as elderly people are often restricted due to transportation means. Sustained and multifaceted strategies are necessary for better immunization coverage.