N Engl J Med. Spread of a Novel Influenza A (H1N1) Virus via Global Airline Transportation

[Giuseppe]

NEJM -- Spread of a Novel Influenza A (H1N1) Virus via Global Airline Transportation

Correspondence

Published at www.nejm.org June 29, 2009 (10.1056/NEJMc0904559)

Spread of a Novel Influenza A (H1N1) Virus via Global Airline Transportation


To the Editor:

Throughout March and April 2009, international air travelers departing from Mexico were unknowingly transporting a novel influenza A (H1N1) virus1 to cities around the world. We analyzed the flight itineraries for all passengers departing from commercial airports in Mexico between March and April 2008, using data from the International Air Transport Association (IATA). The purpose of this analysis was to show how travelers ? and consequently to predict how H1N1 ? would disseminate worldwide during the initial wavefront of this epidemic. We analyzed IATA data from March and April 2008 for the following reasons: the data accounted for more than 95% of all passenger trips worldwide via commercial airlines, they included information on the flight origins and destinations of actual passengers, data on passenger itineraries for the period from March through April 2009 were unavailable at the time of this analysis, the global pattern of passenger departures from Mexico between March and April varies minimally from year to year, and the epidemic in Mexico was largely unrecognized during the period from March through April 2009, with passenger departures presumably following their usual seasonal pattern.
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<cite cite="http://content.nejm.org/cgi/content/full/NEJMc0904559">NEJM -- Spread of a Novel Influenza A (H1N1) Virus via Global Airline Transportation</cite>

[the doctor]

Re: N Engl J Med. Spread of a Novel Influenza A (H1N1) Virus via Global Airline Transportation

By tracking commercial airliner traffic from Mexico from March through April of 2008 to other places in the world, these Canadian investigators were able to predict with an accuracy of >80&#37; the pattern of worldwide flu spread seen after May 2009.

What this study confirms is the novel H1N1 pandemic strain has been spread primarily by people traveling by commercial aircraft from Mexico to other parts of the world in the spring of this year.

Grattan Woodson, MD