LONDON (AP) -- Dutch scientists ignited a controversy Friday by suggesting that children would be better off skipping the seasonal flu vaccine this year -- a proposal flatly rejected by other health experts.

Their commentary, based largely on animal studies, was published online Friday in the British medical journal Lancet Infectious Diseases. The theory is that children infected with seasonal flu acquire a certain kind of immunity that might protect them against new flu outbreaks like swine flu or bird flu.

Other health officials said there was no proof that children are more likely to avoid swine flu by passing on a seasonal flu shot.

In the opinion piece, Guus Rimmelzwaan of Erasmus University and his colleagues suggested that health authorities reevaluate the recommendation by countries like the U.S. and Canada to give all healthy children between 6 months and 5 years old a flu shot. The World Health Organization recommends that healthy children under 2 get a flu shot.

In the 1957 Asian flu pandemic, the Dutch scientists noted that people infected with seasonal flu were less likely to catch the pandemic virus. They also cited data showing the same trend in mice and ferrets, the latter of which are believed to be a good model for flu in humans.

Other health experts said it would be dangerous to revise flu policies now for results based mainly on animal experiments.

"This is an interesting theory, but it does not reflect what we see in human populations," said Ville Peltola of Turku University Hospital in Finland, who co-authored an accompanying reaction piece in same medical journal.

Peltola said the study might also confuse parents.

"Skipping seasonal flu vaccine does not protect from swine flu, but it leaves the child without protection against seasonal flu," he said. Children under 2 are among the highest risk group of developing complications from seasonal flu, which kills up to 500,000 people worldwide every year.

"The best shot parents have at protecting their kids is to get them a shot in the arm or up the nose," said Dr. Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota. "Parents should get whatever vaccine is available and approved."

Osterholm said there was no biological reason why a seasonal flu infection might ward off swine flu. If that were the case, countries with low rates of seasonal flu vaccination -- such as Mexico -- would not have had a big swine flu problem.

"There is no evidence of a reduction in H1N1 in places where the flu vaccine hasn't been used," he said.

WHO said their flu vaccine recommendations remain unchanged.

"Flu vaccine is one of the most important tools we have against influenza," said spokesman Gregory Hartl. "Children are one of the groups most affected by seasonal flu and we recommend they continue to get vaccinated."

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