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