The Japanese experience with vaccinating schoolchildren against influenza

The landmark study by Reichert et al. (2001) systematically analyzed the impact of Japan’s national policy to vaccinate schoolchildren against influenza on overall and pneumonia/influenza-associated mortality, spanning 1949–1998 Historically, influenza-control strategies worldwide have focused on vaccinating the elderly and high-risk populations because of their susceptibility to severe outcomes. Japan, however, from 1962 to 1987, uniquely implemented a policy of mass immunization of schoolchildren, based on epidemiologic insights that children are primary amplifiers and disseminators of influenza transmission Using robust epidemiological methods, the authors compared seasonally adjusted mortality rates for all causes and for pneumonia/influenza in Japan and the United States, calibrated against baseline (November) mortality. Vaccine distribution records were integrated to quantify coverage. The analysis revealed that, prior to widespread school-based vaccination, Japan’s winter excess mortality was three to four times higher than in the United States. Following policy implementation, excess mortality declined sharply, converging with US levels—even as Japan’s elderly population...