Catch your flight—not a disease
Before you fly, take a moment to consider whether you risk spreading disease to fellow passengers-or vice versa. "People know tuberculosis, colds and flu are contagious," said Dr. David Streitwieser, medical director for MedAire's MedLink Service. "What may not be as well known is that rashes such as chicken pox and the varicella virus [shingles] are also spread by both inhaling and direct contact."
Streitwieser cautioned against relying on face masks in flight to prevent the spread of disease. "Masks are helpful," he said, "but the best disposable mask is about 95 percent effective and the standard mask available on the open market that is not custom fit is probably going to reduce effectiveness by 75 percent."
Infection can occur by simply touching an object as much as several hours after it has been contaminated, Streitwieser explained. He said that passengers who touch things in public places should wash their hands and avoid touching their nose, mouth or eyes. Indeed, washing your hands-frequently and thoroughly with soap and warm running water-is one of the best things you can do to avoid catching and spreading infection.
While you can contract an illness by exposure to a small number of germs, they have to multiply in your body before you become contagious. "A typical incubation period for most respiratory viruses, from exposure to onset of the disease, is several days, with some diseases, such as hepatitis, taking months," Streitwieser said. "The important thing to remember is you can often be contagious before you have the full symptoms."
Severe Acute Respiratory Syndrome- better known as SARS-is among the more lethal viruses to have infected airplane passengers. "One of the really scary things we discovered about SARS was even people who were young and healthy were succumbing to it," said Brad Waite, D.O., medical program director for AirCare International of Olympia, Wash.
"A fair number of people who were caring for SARS victims contracted it themselves," added Waite, who is a board-certified emergency physician. "Those patients were in infectious disease wards but it didn't seem to matter at all.
"I think SARS is more infectious than TB or influenza," Waite said. "People were being infected at a greater distance from the carrier than you'd expect.
"SARS hasn't been seen since the 2003 outbreak," Waite added. "That doesn't mean it won't raise its ugly head again. It hasn't been eradicated; it just went into hiding."
Aircraft ventilation systems are better than the media would lead people to believe, Waite suggested. "Most aircraft built in the last 10 years have better quality air circulation than most office buildings, and HEPA [high-efficiency particulate air] filters are becoming common in newer aircraft." HEPA filters are capable of removing 99.97 percent of airborne particles 0.3 micrometers in diameter or larger, which includes tuberculosis.
The news earlier this year of an Atlanta lawyer who took several airline flights despite having been diagnosed with multidrug-resistant tuberculosis shocked the public. He flew from the U.S. to Europe to attend his wedding and then to Canada before heading back into the States, making it doubly shocking in that there were so many missed opportunities to stop him along the way. However troubling that situation was, Waite feels it's not quite as bad as it might appear.
"If you look at the World Health Organization recommendations for following up on TB exposure, they suggest passengers up to two rows on either side [of the infected passenger] should be checked," Waite said. "The fact is, there never have been confirmed transmissions of tuberculosis in an aircraft. There have been one or two instances when someone's test turned positive but you can be infected with TB and never actually get the disease."
Waite recommends that anyone who has been exposed to the TB bacillus and develops a positive skin test be treated, but he said it is largely a preventive measure in case the patient's immune system deteriorates. "When that happens," he explained, "the body's control mechanisms don't function properly and it becomes possible to develop the active disease. However, significant exposure is required for it to develop. Having said that, people who have TB are advised to delay travel until they're no longer contagious. Normally, that [requires] about two weeks of treatment, provided the disease isn't a multiple drug resistant strain.
"The truth is, influenza spreads much more easily than TB and anyone who has an acute respiratory problem, such as a cough and fever, shouldn't fly," he continued. "The longer the flight and the smaller the cabin, the more important that becomes. If it is absolutely necessary for [a passenger] to fly, the pilot should assure the individual is kept as far from others as possible and the passenger should wear a mask."