The Japanese Experience with Vaccinating Schoolchildren against Influenza
The New England Journal of Medicine -- March 22, 2001 -- Vol. 344, No. 12
Thomas A. Reichert, Norio Sugaya, David S. Fedson, W. Paul Glezen, Lone Simonsen, Masato Tashiro
Abstract
Background. Influenza epidemics lead to increased mortality, principally among elderly
persons and others at high risk, and in most developed countries, influenza-control efforts focus
on the vaccination of this group. Japan, however, once based its policy for the control of
influenza on the vaccination of schoolchildren. From 1962 to 1987, most Japanese
schoolchildren were vaccinated against influenza. For more than a decade, vaccination was
mandatory, but the laws were relaxed in 1987 and repealed in 1994; subsequently, vaccination
rates dropped to low levels. When most schoolchildren were vaccinated, it is possible that herd
immunity against influenza was achieved in Japan. If this was the case, both the incidence of
influenza and mortality attributed to influenza should have been reduced among older persons.
Methods. We analyzed the monthly rates of death from all causes and death attributed to
pneumonia and influenza, as well as census data and statistics on the rates of vaccination for
both Japan and the United States from 1949 through 1998. For each winter, we estimated the
number of deaths per month in excess of a base-line level, defined as the average death rate in
November.
Results. The excess mortality from pneumonia and influenza and that from all causes were
highly correlated in each country. In the United States, these rates were nearly constant over
time. With the initiation of the vaccination program for schoolchildren in Japan, excess mortality
rates dropped from values three to four times those in the United States to values similar to
those in the United States. The vaccination of Japanese children prevented about 37,000 to
49,000 deaths per year, or about 1 death for every 420 children vaccinated. As the vaccination
of schoolchildren was discontinued, the excess mortality rates in Japan increased.
Conclusions. The effect of influenza on mortality is much greater in Japan than in the United
States and can be measured about equally well in terms of deaths from all causes and deaths
attributed to pneumonia or influenza. Vaccinating schoolchildren against influenza provides
protection and reduces mortality from influenza among older persons. (N Engl J Med
2001;344:889-96.)
Source Information
From Becton Dickinson and Entropy Limited, Upper Saddle River, N.J. (T.A.R.); the
Department of Pediatrics, Nippon Kokan Hospital, Kawasaki, Japan (N.S.); Aventis
Pasteur-MSD, Lyons, France (D.S.F.); the Influenza Research Center, Baylor College of
Medicine, Houston (W.P.G.); the National Institute of Allergy and Infectious Diseases,
Bethesda, Md. (L.S.); and the National Institute of Infectious Diseases, Tokyo, Japan (M.T.).
Address reprint requests to Dr. Reichert at 262 W. Saddle River Rd., Upper Saddle River, NJ
07458, or at doctom_us@yahoo.com.
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