SEATTLE, Sept. 11 (UPI) -- A vaccination program that targets children first and reaches 70 percent of the U.S. population would mitigate pandemic influenza H1N1, researchers said.

Ira Longini and colleagues at the Vaccine and Infectious Disease Institute at Fred Hutchinson Cancer Research Center in Seattle used computer models to determine what would mitigate the H1N1 pandemic.

The researchers said that to bring the swine flu epidemic under control aggressive vaccination of the population must begin at least a month before the epidemic peak, concentrating on children as much as possible.

The study, published in Science Express, the early online edition of the journal Science, recommends children ages 6 months to 18 be vaccinated first, as well as those with chronic diseases and those working in healthcare and emergency services personnel.

Although social distancing and the use of antiviral medicines can be partially effective at slowing pandemic flu spread, vaccination remains the most effective means of pandemic influenza control, the study authors said.

From a cost effectiveness aspect, vaccination remains the most effective measure, while closing schools and other social gathering places is the least cost effective, the researchers said.