Featured Research

from universities, journals, and other organizations

A Public Health Lesson From 9/11: To Curb The Flu, Limit Flights

Date:
September 17, 2006
Source:
Children's Hospital Boston
Summary:
A detailed analysis of influenza patterns indicates that the sharp dip in air travel after September 11, 2001, slowed flu spread and delayed the onset of the 2001-2002 U.S. flu season, report researchers at Children's Hospital Boston. Their findings suggest that limiting airline volume could buy critical time during a flu pandemic.

Seasonal variability in the regional timing of influenza mortality in the United States (1996-2005).
Credit: Image courtesy of Public Library of Science

A detailed analysis of influenza patterns indicates that the sharp dip in air travel after September 11, 2001 slowed flu spread and delayed the onset of the 2001-2002 U.S. flu season, report researchers at Children's Hospital Boston. Their findings, published in the September 12, 2006 issue of the online journal PLoS Medicine, suggest that limiting airline volume could buy critical time during a flu pandemic.

Most previous investigations of the effect of air travel on influenza spread have relied on simulations of flu activity rather than actual data.

"The post-September 11th flight ban was a natural experiment on the effect of flight restrictions on disease spread," says John Brownstein, PhD, the paper's lead author and a faculty member of the Children's Hospital Informatics Program (CHIP) at the Harvard-MIT Health Sciences and Technology program. "For the first time we've been able to show, using real data, that air travel spreads the flu, suggesting that reducing the number of air passengers might ameliorate a flu pandemic."

The spread of avian flu (H5N1) in Asia and Europe, including some likely cases of person-to-person transmission, has intensified debate over whether flight restrictions should be imposed to curb emerging flu pandemics. Both the World Health Organization (WHO) and the United States government are considering such restrictions.

Using data on influenza mortality from the Centers for Disease Control and Prevention (CDC), Brownstein and senior investigator, Kenneth Mandl, MD, MPH, a CHIP faculty member and an attending physician in Children's Department of Emergency Medicine, measured the rate of influenza spread across the U.S. during nine flu seasons, from 1996-97 to 2004-05.

During the first five flu seasons, flu mortality consistently peaked on or around February 17. But in the flu season after September 11, 2001, the peak was delayed until March 2, nearly two weeks later than average. In subsequent years, the peaks moved back toward February 17 as airline activity resumed its pre-9/11 levels.

In addition, analysis of laboratory surveillance data from the WHO and CDC showed that in the 2001-2002 flu season, it took 53 days for flu to spread across the U.S., 60 percent longer than the average time of 33 days.

By contrast, in France, where flight restrictions were not imposed, there was no delay in flu activity during the 2001-2002 flu season.

Brownstein and Mandl, both also of Harvard Medical School, then compared their data on flu spread with monthly estimates of passengers on domestic and international flights, obtained from the U.S. Department of Transportation.

For domestic flights, airline volume in November 2001 was an especially strong predictor of flu spread. With the Thanksgiving holiday, November is typically one of the busiest travel months of the year, but in 2001, many people kept close to home or sought other forms of travel.

"Thanksgiving is when new flu strains often spread across the country," Brownstein notes.

For international flights, volume during September most strongly predicted the U.S. flu peak, suggesting that September is a key month for introduction of foreign flu strains. In September 2001, international flights fell 27 percent (from 4.9 to 3.5 million passengers), and peak flu mortality that winter was delayed by two weeks. In 2002, international travel was still down by 10 percent, and the U.S. peak was again delayed.

"When we first looked at our data we noticed that the 2001-2002 flu season was highly aberrant," Mandl recounts. "At first we thought it was a problem with the data, but then we realized we were seeing the shadow of September 11th cast upon the influenza season."

The research was funded by a grant from the National Library of Medicine.


Story Source:

The above story is based on materials provided by Children's Hospital Boston. Note: Materials may be edited for content and length.


Cite This Page:

Children's Hospital Boston. "A Public Health Lesson From 9/11: To Curb The Flu, Limit Flights." ScienceDaily. ScienceDaily, 17 September 2006. <www.sciencedaily.com/releases/2006/09/060915204607.htm>.
Children's Hospital Boston. (2006, September 17). A Public Health Lesson From 9/11: To Curb The Flu, Limit Flights. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2006/09/060915204607.htm
Children's Hospital Boston. "A Public Health Lesson From 9/11: To Curb The Flu, Limit Flights." ScienceDaily. www.sciencedaily.com/releases/2006/09/060915204607.htm (accessed April 19, 2014).

Share This



More Health & Medicine News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nine-Month-Old Baby Can't Open His Mouth

Nine-Month-Old Baby Can't Open His Mouth

Newsy (Apr. 19, 2014) Nine-month-old Wyatt Scott was born with a rare disorder called congenital trismus, which prevents him from opening his mouth. Video provided by Newsy
Powered by NewsLook.com
'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins