流感疫苗对孩子也是安全有效

One of the first studies of the effectiveness of flu vaccine in young children suggests that vaccination should be considered for youngsters before they reach their first birthday.

Older adults are considered to have the greatest chance of dying from the flu, but young children are also very much at risk. Not so much of dying, but certainly of getting sick with complications that can require a hospital stay.

Only a few countries currently vaccinate young children against the flu. The United States is one. Another is Finland, where Dr. Terho Heikkinen of the University of Turku led this new study.

"The problem has been that there has been no clear data on the efficacy of the vaccine in the youngest children," says Heikkinen. "And therefore, many countries, although they think that influenza is an important illness in young children, they have been reluctant in moving forward in vaccination until some convincing data are available."

Heikkinen and his colleagues set out to provide that convincing data.

Children in their study ranged from nine months to just over three years old. As a whole, those who were vaccinated were less likely to get the flu. That was especially true among the youngest, those under age two. In that group, 12 percent of those who did not get a vaccination came down with flu, but only four percent who were fully vaccinated got the disease.

"This is the first study that clearly shows that the inactivated vaccine that's available for young children these days is clearly effective, even in the age group younger than two years," he said.

The results of vaccination are actually better than those numbers suggest. In the 2007-2008 flu season, when this study was conducted, the vaccine was designed to protect against two varieties of the flu, but it turned out to be largely ineffective against type B. Against type A influenza, 10 percent of the unvaccinated under-twos got sick, but only two percent of those who were fully vaccinated got the flu.

Heikkinen does not say that young children should start getting flu shots. But he said his study - and one other study that examined the issue a few years ago - both concluded that flu vaccines can be effective and safe for this age group, so policy makers, doctors, and parents ought to at least think about it.

"I believe that the vaccine recommendations of young children will be at least reconsidered in all countries that do not vaccinate at this time."

Terho Heikkinen's study is published online by the journal, The Lancet Infectious Diseases.