Dr. Raymond Fong – a consultant infectious diseases at Changi General Hospital – had commented in response to my earlier post on legal aspects of tuberculosis management that one other challenging issue sometimes faced by doctors was with regards to air travel and tuberculosis.

There have been a number of incidents regarding passengers and crew members of commercial airlines that had been exposed to tuberculosis during flights, the most famous of which remains undoubtedly the 2007 tuberculosis scare involving U.S. lawyer Andrew Speaker. Briefly, he was probably asymptomatic, and was diagnosed to have pulmonary tuberculosis after several investigations including PPD testing, CT thorax, and bronchoscopy (an incidental chest X-ray for rib pain after a fall showed a spot in his lung). He was subsequently told he had multidrug-resistant tuberculosis, but that he was not infectious. Although he was still advised not to travel, he flew off to Greece for his wedding. While in Rome for his honeymoon, the U.S. Centers for Disease Prevention and Control (CDC), believed that he actually had extensively drug-resistant tuberculosis (although this turned out to be incorrect) and tried to persuade him to turn himself in to the Italian health authorities. Because he believed that the CDC had no means of getting him back to the U.S.A., he arranged to fly from Rome to Prague and then to Montreal, before driving back via the U.S. – Canadian border. He was finally detained and placed under involuntary isolation in Denver, following which he attempted to sue CDC for disclosing his identity and medical condition (this was finally dismissed after a round of appeals in 2012).

Probably partially as a result of this case, the WHO updated its guidelines on the prevention and control of tuberculosis and air travel in 2008 (3rd edition).

Cover page of the WHO Guidelines on TB and Air Travel, 3rd edition (2008).

What do the guidelines say about air travel for patients with tuberculosis? Basically, it is quite straightforward and only applies to patients with infectious tuberculosis (i.e. pulmonary or less commonly laryngeal tuberculosis only – tuberculosis infecting other organs are practically considered non-infectious, given that tuberculosis spreads mainly via aerosols).

1. Patients with pulmonary tuberculosis can only fly on commercial flights if their sputum is negative for the organism (acid-fast bacilli) on microscopy on at least 2 separate occasions.
2. However, if the patient has multi- or extensively drug-resistant tuberculosis, then he or she should not travel unless he/she has documented at least two consecutive negative sputum cultures for tuberculosis.
3. The physician’s responsibility is to inform the patients and warn them against taking commercial flights if they fall under the above categories. He/she has to inform the public health authority of the country if he/she believes any patient intends to travel against advice, and also if he/she is aware of any exceptional circumstances that require the patient to fly.
4. The physician also has a responsibility to inform the public health authority if he/she is aware that a patient had taken a commercial flight up to 3 months prior to the diagnosis of pulmonary tuberculosis.
5. The public health authority should contact the airline is a patient with pulmonary tuberculosis had taken a flight of at least 8 hours duration in the preceding 3 months prior to diagnosis.
6. A contact investigation can be carried out after risk assessment by the public health authority, with a request for assistance from international bodies (WHO, CDC, ECDC, etc.) if required, and if more than a single country is involved.

There are some practical issues that have to be worked through however. One of the more common scenarios (albeit for a relatively rare condition) involves medical tourists who come to Singapore for treatment of their illnesses and are subsequently found to have tuberculosis. Physicians from the TB Control Unit described the management of an Indonesian patient with extensively drug-resistant tuberculosis in 2010, where the patient required lung surgery before the disease was brought under control. She stayed in Singapore for at least 7 months, incurring a cost that was estimated to be upwards of SGD100,000.00. Because Mycobacterium tuberculosis complex grows relatively slowly, it takes some 4-6 weeks before the laboratory is confident that there is no growth of MTC from a specimen. Under WHO’s guidelines, medical tourists who are diagnosed with multi- or extensively drug-resistant tuberculosis in Singapore will not be able to leave the country for months (although I am aware of at least one such patient who left Singapore via ferry), which involves a significant cost given that Singapore is by no means a cheap country to live in. What if they are unable to bear this cost?