The immune response was robust for all these children regardless of age, previous antibody status, or whether the child had received a seasonal flu shot, the researchers found.
Nolan noted that ongoing studies are testing whether one 7.5-microgram dose is enough to confer full protection from the H1N1 flu.
Based on the findings of this study and others, health officials around the world may want to reconsider the recommendation about the number of shots and doses children need to be protected, he said.
Dr. Anthony E. Fiore, a medical epidemiologist in the influenza division at the U.S. Centers for Disease Control and Prevention and co-author of an accompanying journal editorial, said that although the studied showed a good immune response to a single dose, "we would like to see additional studies."
Fiore noted that data from seasonal flu vaccine suggests that two doses are "the best choice for children under the age of 10. It's premature to go to the next step and say children only need one dose of the H1N1 vaccine," he said.
Parents should not rely on this study if their child received only one dose of the H1N1 flu vaccine, Fiore said.
"Don't relax based upon this study, thinking they don't need that second dose, because they really do to be certain and provide a level of an immune response that we are more confident is going to protect them," he said.
Infectious disease expert Dr. Marc Siegel, an associate professor of medicine at New York University in New York City, noted that last week's recall of children's H1N1 flu vaccine because it was not potent enough may be much ado about nothing.
Almost 800,000 children's doses of H1N1 swine flu vaccine were
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