Influenza takes off with flights: Study

Researches at the Harvard University have provided concrete evidence that air travel plays a vital role in spreading the deadly influenza virus.

Under the study the researchers from Harvard University examined records of deaths attributed to flu and pneumonia, from nine U.S. regions, between 1996 and 2005. The report published in the PLoS Medicine journal linked the two week delay in the onset of the winter's flu season in the U.S. to the drop in air travel after the September 11, 2001, terrorist attacks.

In the U.S, it takes about 33 days for the flu virus to spread across the country having its peak fixed at around February 17. However the study records revealed that season’s peak shifted to March 2, taking around 53 days to spread in the 2001-02 session.

“As result of the 9/11 flight ban and reduced flying, the introduction of new strains was delayed," John Brownstein, an epidemiologist at Children's Hospital of Boston, who led the research, said.

Spreading quite easily through cough, sneeze and dirty hands, new and more deadly flu strains emerge every few decades leading to onset of worldwide epidemics.

The study claims to be the first one that links contribution of airline travel to the spreading of flu. Based on real life data the study stands different from the other ones that are based on computer generated models.

Brownstein said, “This was a natural experiment to test the effect of flight restrictions. The public health message is that there might be some value to limiting air travel at the beginning of a pandemic .Airline restrictions can't prevent the pandemic strain from coming to us, but restrictions can give us some amount of time to prepare." He indicated that the study could be used by policy makers as evidence in the decision making process.