WASHINGTON -- Studies of the new swine flu vaccine show children 10 and older will need just one shot for protection -- but younger kids almost certainly will need two.
Protection kicks in for older children within eight to 10 days of the shot, just like it does for adults, the National Institutes of Health announced Monday.
But younger children aren't having nearly as robust an immune reaction to the swine flu vaccine, and it appears they'll need two shots 21 days apart, said Dr. Anthony Fauci, head of NIH's National Institute of Allergy and Infectious Disease.
That's not a surprise because the very young often need two doses of vaccine against regular winter flu the very first time they're immunized against that version of influenza, too, Fauci said.
In other developments Monday:
The U.S. ordered more swine flu vaccine, bringing its eventual total to 251 million doses, up from the long-planned 195 million doses. Normally, fewer than 100 million people get a winter flu shot.
The extra orders were from Sanofi Pasteur's Pennsylvania flu-shot factory and from Maryland-based MedImmune LLC, which makes a nasal-spray version.
Heart patients who catch the flu may have more to worry about than just a fever or the sniffles: The virus also could spark a heart attack, new research shows.
Amid the global outbreak of swine flu, experts say it's crucial heart patients get vaccinated against both regular flu and swine flu to avoid medical problems. Doctors said swine flu isn't any more dangerous than regular flu, but it's important for heart patients to get vaccinated because more flu viruses will be circulating this year.
British researchers analyzed 39 previous studies of heart patients and found a consistent link between flu and heart attacks. Up to half of all unexpected flu deaths were because of heart disease, the researchers found.
The study was published online today in the British medical journal, The Lancet Infectious Diseases.
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