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A new report claims that a mass
influenza (flu) vaccination campaign in Japan between 1962
and 1987 prevented one death in the
elderly for every 420 children vaccinated -- resulting in 37,000
to 49,000 lives saved every year. At that time, very few elderly Japanese
or others at high risk were given the vaccine, the strategy used in the
US and other countries to prevent flu deaths.
The investigators were working on the premise that
vaccinating the elderly only protects about half of those immunized. Targeting
children creates what researchers call "herd
immunity" - protection against infection that susceptible
people get when most of the population is immune to a virus.
Since 1997, Japan has recommended
that the elderly and other high-risk
individuals receive flu shots, which will allow researchers
to determine which strategy is most effective.
Japan launched its previous campaign in the early
1960s, after a devastating flu epidemic was blamed for about 8,000 deaths
over two seasons and led to widespread school closures.
By the late 1980s, 50%
to 85% of all Japanese schoolchildren had been immunized against influenza.
But lawsuits alleging adverse
side effects and skepticism over the campaign's effectiveness
caused the rate of vaccination to plummet and by 1994, Japan's program
ended. Soon, the report indicates, flu-related deaths among the elderly
began to climb.
After Japan launched the vaccination campaign, the
rate of influenza-related death dropped to levels equal to those in the
US despite an increase in the number of elderly people. Earlier, the rate
of death from influenza in Japan was 3- to 4-times higher than in the
US.
The New England Journal
of Medicine March 22, 2001; 344: 889-896
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