The estimated impact of the 5-year national vaccination program on the trend of 23-valent pneumococcal polysaccharide vaccine vaccination rates in the elderly in Japan, 2009-2018.

Pneumonia is the third most common cause of death in Japan. Low vaccination rates are thought to be related to low levels of public subsidy. Since 2014, the Japanese government has offered subsidies through a 5-year national routine vaccination program of the 23-valent pneumococcal polysaccharide vaccine (PPV23) for older adults at age ≥65 years with 5-year age intervals. We previously reported that, 2 years into the 5-year program, the estimated vaccination rate was 40.6% at the end of 2015, a significant increase compared with periods before the program introduced. Here, we present an update on the estimated vaccination coverage of the 5-year national routine vaccination program at the end of 2018. The PPV23 vaccination rates were calculated by dividing the cumulative amount shipped to each municipality by the population aged ≥65 years. At the end of 2018, the completion of the 5-year national immunization program, the estimated cumulative vaccination rate was 74%. Stepwise regression analysis revealed that the annual PPV23 vaccination rate significantly increased after 2014 (from 2 to 5% prior to 2014, to 10-11% after 2014), and remained steady for 2014-2018. Our findings suggest that the 5-year national routine vaccination subsidy program was successful in achieving a steady and higher vaccination rate of PPV23 in Japan.