The facts of TB transmission in travel

The facts of TB transmission in travel

JAKARTA: The World Health Organization (WHO) has issued
Tuberculosis and Air Travel: Guidelines for Prevention and
Control to inform the world's 1.4 billion air passengers and
airlines on preventing transmission of the disease.

WHO stresses the risk remains low although transmission during
air travel has been documented. Airlines, passengers, physicians
and health authorities need to be informed on measures to
minimize risk of infection and prevent development of active TB
when infection does occur.

"We want to make air travel safer, reduce the risk of TB
transmission and increase passengers' confidence that they are
adequately protected from risk of infection when they travel,"
said Dr. Mario Raviglione of WHO's Communicable Disease
Operational and Epidemiological Research unit.

"We are confident that these guidelines will be a substantial
aide in achieving that goal."

The effort has been welcomed by the airline industry.
According to Dr. Claus Curdt-Christiansen of the International
Civil Aviation Organization (ICAO), TB ranks as "one of the most
vexing aeromedical problems of modern air transportation" because
of the prevalence of air travel.

"Within the next decade we an expect more than two billion
passengers per year in scheduled air traffic alone," he said.
"Long-haul flights combined with the confined space of a
passenger cabin and the close proximity to copassengers from the
entire world may facilitate the spread of contagious diseases.

"In-flight exposure to infectious tuberculosis from
copassengers has become a realistic airline possibility owing to
the high prevalence of tuberculosis in some regions of the world.
It is to be hoped WHO's guidelines will be studied by all doctors
related to the airline industry and its regulatory agencies, and
that the recommendations given will be implemented without delay
by health authorities and airline companies worldwide."

The guidelines were produced in collaboration with
international TB experts, civil aviation authorities and airline
company representatives. They recommend tracing and informing
passengers and crew members who were on a commercial flight with
an infectious person, if the flight, including ground delays
(during which passengers remain on board the aircraft with little
or no ventilation), lasted more than eight hours. This is to be
done if less than three months have elapsed between the flight
and notification of the case to the health authorities.

The guidelines were prompted by increasing reports of TB
outbreaks on airlines. However, between 1992 and 1996 in studies
involving seven patients with active TB and 2,600 passengers and
crew with whom they had contact, the U.S. Centers for Disease
Control and Prevention (CDC) found only a few instances of TB
transmission.

But because airlines have not always had the proper mechanisms
in place to follow-up on passengers, CDC was not able to reach
all passengers on the flights where transmission occurred. There
may consequently be many additional unreported cases.

Once cases are notified by the health authorities, airline
companies should inform passengers and crew of possible exposure
and encourage them to establish whether infection might have
occurred and whether preventive therapy is needed, the guidelines
say.

Incomplete airline records (either because no passenger
details have been recorded or those recorded are incorrect) would
make this difficult. WHO says it is essential that airlines
maintain as comprehensive and reliable records as possible.

In addition, maximum efficiency air filters should be
installed and properly maintained on all aircraft and ground
delays kept to a minimum. Anyone with infectious TB should
postpone travel until they become noninfectious. Boarding can and
should be denied to people known to have infectious TB.

The Aerospace Medical Association and the Airline Medical
Directors Association also support the recommendations.

Ten Recommendations

For travelers:

* Persons with infectious TB should postpone travel until they
become noninfectious.

For physicians and health authorities:

* After assessing a recent (i.e. within three months) history
of air travel in a patient with suspected or confirmed active TB,
physicians should immediately inform the health authority, in
addition to submitting the required notification for a TB case.

* Health authorities should promptly contact the airline
company if a person with infectious TB is known to have traveled
on commercial aircraft in a flight of at least eight hours'
duration within the preceding three months.

For airline companies:

* Airline companies should cooperate fully with health
authorities in determining whether informing passengers and crew
of potential exposure to M.tuberculosis is indicated and which
passengers to inform.

* Airline companies should cooperate fully with health
authorities in informing passengers and crew when potential
transmission of M.tuberculosis is suspected.

* In order to inform promptly passengers of any potential
health risk (exposure to M.tuberculosis or other infectious
diseases, exposures to toxins, etc.), airline companies should
require home or work addresses and telephone numbers for all
passengers.

* Airline companies should ensure that all crew receive
adequate training in first aid and in using universal precautions
when there may be exposure to body fluids. They should also
ensure that adequate emergency medical equipment/supplies are on
all aircraft (including gloves, HEPA masks, and biohazards
disposal bags).

* Airline companies should have prearranged access to
physicians with expertise in communicable diseases who are
readily available to consult with health authorities.

* Records of all illnesses and medical emergencies occurring
abroad should be kept for at least three years.

* Ground delays should be kept at a minimum, and HEPA filters
with maximum efficiency (99.97 percent at 0.3 microns) should be
installed and properly maintained on all aircraft.

-- WHO