Japanese child flu vaccine aided elderly: study

BOSTON - A now-abandoned Japanese programme that vaccinated 20 million schoolchildren against the flu probably prevented tens of thousands of deaths among the elderly and infirm each year, according to a study in Thursday's New England Journal of Medicine.

Dr Thomas A Reichert and his colleagues from Japan, the United States and France used health data from the US and Japan to conclude that the influenza death rate was three to four times lower in Japan during the vaccination programme than it was before or after the childhood immunizations.

They said immunized children created a barrier that slowed the spread of the flu, a phenomenon known to biologists as herd immunity.

When the Japanese stopped making the shots mandatory in 1987, the death rate began to rise.

"The vaccination of Japanese children prevented about 37,000 to 49,000 deaths per year, or about 1 death for every 420 children vaccinated," the researchers said.

The Reichert group said the results, if confirmed, should encourage health officials to consider giving the flu vaccine to children.

Japan is the only country to attempt to control the spread of the influenza virus by vaccinating its children instead of the elderly. An epidemic in 1957 taught the Japanese that youngsters play a big role in spreading the disease.

Childhood flu vaccinations began in 1962 and became mandatory in 1977. But in 1987, parents were allowed to decline the vaccine for their children. The programme was discontinued in 1994 because of doubts about the programme's effectiveness and fears that the vaccines were harming children.

The Reichert team found that the death rate for pneumonia and the flu, which had traditionally been much higher than in the US, declined by half between 1962 and 1972, and dropped by another 40 percent between 1972 and 1987.

"The Japanese rates rose steadily after 1987, and more steeply after 1994, to values similar to those in Japan before 1962," they found. "A correspondence between these changes and the rate of use of vaccine in both countries is clear."

At the time, researchers did not look at the death rates among the elderly or chronically ill when the vaccination programme was under way.

"Only with the discontinuation of the programme have its effects become clear," they said.

It was not until 1997 that Japan began recommending the influenza vaccine for elderly people and people with chronic medical conditions, the researchers said.