Rewind: We published the following blog post last spring on how airports worldwide are reacting to the threat of swine flu (H1N1 virus). Worth a second look as local TV news stations nationwide hype the use of fever scanners overseas.

April 30: Hong Kong's main airport may be the world's most aggressive when it comes to flu prevention methods. Since 2003, arriving passengers have had to walk through "fever scanners." The body-heat sensors, which look like metal detectors, scan to see if a passenger is feverish.

If the body temperature is 100 degrees Fahrenheit or higher, a red image shows up on a computer screen. Officials then pull the passenger aside for secondary screening (such as a throat examination, etc.), in case he or she might be a carrier of a contagious flu or a virus that may cause a potentially fatally pneumonia. Passengers with a confirmed fever are detained and sent to a clinic for additional observation. If doctors find symptoms of a respiratory illness and the traveler has passed through a city with a confirmed swine-flu outbreak, the traveler will be quarantined at a hospital for two or three days until tests could confirm the presence of the flu.

Australia is rushing to add the body-heat scanners to their airports. A handful of other international airports also use the fever screening machines, including Indonesia's, Malaysia's, and Taiwan's main international airports.

But are the $50,000 body-heat scanners worthwhile? French researchers recently tried to find out. They ran a study on the accuracy of the fever detectors on more than 2,000 people, comparing their temperature readings at a distance with the use of the standard thermometer. The scanners only detected one out of six people who had fevers and illnesses. That's an awful lot of people slipping through the system. The body-heat machines also falsely reported lots of people as having fevers who turned out not to have fevers, inconveniencing them at the airport checkpoints.

In an interview with a New York Times article, Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention, said:

When Hong Kong was hit with severe acute respiratory syndrome, or SARS, "increased border screening on entry and exit was not an effective way of identifying cases or preventing transmission."

One reason is that passenger screening might not work with swine flu because the symptoms often show up two to seven days after the person has become contagious.

But some of the ideas that Hong Kong airport workers have seem pretty smart to me. They're putting up "fresh sheets of plastic film over elevator buttons so that any sick people pressing the buttons would not share their germs with too many people who pressed the same buttons later," reports the New York Times. Every little measure like that has got to help slow the spread of an illness.