"This is the first time that a study's been able to show a direct link between the numbers of people traveling and the rate of spread of a virus," said John Brownstein, an epidemiologist at Children's Hospital, who led the new research.
However, there is no proof in the study that air travel restriction will actually help in future, since there was only a postponement and not a reduction in the number of deaths, argue other scientists. Moreover, if a pandemic were to strike, would a 2-week delay be more important than the financial turmoil of severe restriction of travel.
"You wouldn't want to have people look at this and say, `Ah, this is overwhelming evidence that if the pandemic occurs, we should shut down air travel," said Dr. Anthony Fauci of the National Institutes of Health, the government's chief influenza specialist. "What does it buy you? That's the real critical issue."
Added Dr. William Schaffner of Vanderbilt University, who advises the government on flu issues: "We're all sure that airlines play a role. . . . Leaping from this sort of analysis to interdiction of air travel I think is provocative, and we have to be very careful about that."
The flu is spread by people through coughs, sneezes and germy hands. However, scientists fail to comprehend how a community outbreak moves outward until every year's flu strain spreads across countries.
In addition, a new and potent flu strain develops every few decades and causes worldwide epidemic.
To curb the next epidemic, a better understanding of those geographic patterns is required.
According to earlier reports, small children who bring the flu home and spread it to elders generate community outbreaks. This spreads between the cities and states in the U.S. when these sick elders go to work.
The government data on flu and pneumonia deaths in 9 U.S. regions during the period 196-2005 were examined by the scientists.
Brownstein, who conducted the study with Dr. Kenneth Mandl, a pediatric emergency physician at Children's, said, "The study's findings suggest that if a flu pandemic began, air travel restrictions might buy a little time for health officials to take such steps as rounding up medications. But we're not saying we could prevent the pandemic just by travel restrictions," he emphasized.