Fly without fear of catching TB
|Fly without fear of catching TB
Dr. Marc Siegel
June, 5 2007
Working on the chest ward at Bellevue Hospital, I often took care of
patients with drug-resistant tuberculosis.
Andrew Speaker, the young Atlanta attorney now quarantined in Denver, has a
form of TB that is extensively resistant.
But as soon as his phlegm tested negative for the bacteria, doctors at
Bellevue and his other hospital stops probably removed their masks, as I did
with my patients.
No doubt they also allowed him to move around the ward and ultimately to
leave the hospital. This is not so irresponsible as it sounds: The risk of
infecting anyone with TB is very low when a patient lacks symptoms and none
of the culprit bacteria is found in his mucous.
This case was reportedly found by coincidence on an X-ray and subsequently
confirmed on a culture. Unlike most patients with TB, Speaker has never
coughed or had fevers or lost weight.
Although TB is very difficult to cure, it is not easy to catch. So why am I
receiving so many calls this week from anxious patients worried that they
are going to catch the deadly bacteria on their plane flights? We all tend
to personalize the risk of catching the latest mysterious bug in the news.
Too much media focus makes us feel susceptible when the actual risk is
minimal. We can add "extensively drug-resistant TB" to E. coli, bird flu,
mad cow disease and SARS, remote killers that have made us all paranoid.
Tuberculosis itself is a rampant problem worldwide, with close to 8 million
new cases of acute TB every year, half of which show at least some
resistance to antibiotics. Drug resistance occurs, at least in part, because
of noncompliance with TB medicines. In my practice, the patients who would
ignore travel advisories were generally the same patients who would stop
taking their medicines.
Although Speaker is the first TB patient to be quarantined in 44 years,
according to the Centers for Disease Control and Prevention, he doesn't pose
a significant risk to others. Consider that there have been fewer than 50
cases of this extremely resistant TB in the United States over the past 14
years. Catching any TB requires very close contact. The risk is 20 percent
for close contact with someone sick with active TB. But the risk is probably
much less than 1 percent for passengers on any of Speaker's flights because
he wasn't coughing, had no fever and was receiving some treatment. There has
not yet been a single case of active tuberculosis resulting from exposure on
The CDC has been accused of inadequate public health surveillance in the
Speaker case, but that's not entirely fair. When he boarded a plane to
Europe, the agency was not yet aware that Speaker had the extensively
drug-resistant kind of TB. If public health officials had known, they
certainly would have isolated him beforehand, not because of a high risk of
transmission but because this kind of TB is so difficult to treat that even
a remote theoretical risk is too much to take. Finding extensive drug
resistance after several months' delay should not justify an exaggeration of
the minuscule risk of transmission, but rather be a wakeup call for more
rapid drug-sensitivity tests.
All of us bring viruses and bacteria with us onto airplanes, but our basic
civil rights should protect us from being put through an infectious disease
Geiger counter each time we board. When it comes to tuberculosis, filtering
now in use on airlines (which removes 99.9 percent of viral and bacterial
particles the size of tuberculosis and even smaller) has been shown to
reduce significantly circulating bacteria in an airplane cabin, including
Tuberculosis resides deep in the lungs and is transmitted by deep coughing
and prolonged exposure. Initial infections are generally mild or
undetectable, except by a TB skin test. TB goes on to cause significant
disease in only 5 percent of cases, and many of these patients are
immuno-compromised or suffering from other diseases.
In several studies, transmission of TB has been demonstrated only in flights
much longer than the ones Speaker took. In the early 1990s, six passengers
and one crew member who had active TB (two knew they had TB but didn't
inform the airline; the others found out after the flight) were studied by
the CDC, and their 2,600 contacts were followed. Only a few cases of TB
conversion were found from close contact - on flights longer than eight
hours. These patients (as opposed to Speaker) were all highly symptomatic
and had TB in their sputum, and yet no one got sick from the exposure.
Despite the prevalence of TB in the Third World (it infects one out of three
people worldwide, more than 90 percent in developing countries, and annually
kills more than a million), to date not a single case of active tuberculosis
has been found to be the result of exposure on a plane.
Increased awareness of tuberculosis, a major worldwide killer, is a valuable
public health goal. Instead, the Speaker case has set off an irrational wave
of plane fear.
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