It's no secret that air travel is a big reason for the spread of airborne diseases.
Now, new research out of Children's Hospital in Boston finds a direct connection between the slow down of air travel after 9-11 and a milder flu season during that time.
"After September 11, we turned off for a number of weeks domestic air travel and in fact, there was evidence that this study showed decreased spread of flu," said David Weber, a researcher of infectious diseases.
Dr. Weber says the finding could be useful information in case of a pandemic. Perhaps by restricting air travel, that could give the nation time to stockpile things like food and water and medicine in the event of an impending crisis.
As for this year's cold and flu season, officials say the best way you can protect yourself even if you get a flu shot is frequent hand washing.