5Reducing the risk of exposure to M. tuberculosis on aircraft

Publication Details

5.1. Definition of infectious TB for air travel purposes

National public health authorities should inform international partners if either of the following definitions for infectious TB or potentially infectious TB is fulfilled. For action at national level, national public health authorities may modify these definitions based on more specific criteria in accordance with their national guidelines.

  • Infectious TB. All cases of respiratory (pulmonary or laryngeal) TB which are sputum smear-positive and culture-positive (if culture is available).
  • Potentially infectious TB. All cases of respiratory (pulmonary or laryngeal) TB which are sputum smear-negative and culture-positive (susceptible, MDR-TB or XDR-TB).
  • Non-infectious TB. All cases of respiratory TB which have two consecutive negative sputum-smear and negative culture (if culture is available) results.

Patients with MDR-TB or XDR-TB are considered non-infectious if there is evidence of a clinical response to treatment and two consecutive negative sputum-culture results* have been obtained.

*

After at least 6 weeks of incubation.

Action recommended for each category

  1. For cases of infectious TB: it is recommended to start contact-investigation procedures, taking into consideration national contact-investigation policies.
  2. For cases of potentially infectious TB: additional information should be requested to conduct a risk assessment and determine whether a contact investigation should be considered.
  3. For non-infectious TB cases: no further action is required.

5.2. Precautions before travel

People with infectious or potentially infectious TB should not travel by commercial air transportation on a flight of any duration

People known to have infectious or potentially infectious TB should be advised not to travel on commercial aircraft until there is no longer a risk of transmitting infection to others, i.e. until they become non-infectious. If, under exceptional circumstances, travel on a short flight is essential while a person is still infectious, commercial carriers or other public transportation should not be used. Alternative private transportation (e.g. ground ambulance transportation, air ambulance, private carrier) should be considered. If the use of commercial carriers is unavoidable (e.g. transfer to a tertiary care facility), a specific travel protocol should be agreed upon in advance between the public health authorities and airline(s) involved in the countries of departure, arrival and any transit points, and strictly applied.

Symptoms of pulmonary TB are not specific (e.g. cough) and people with TB are often infectious long before the disease is diagnosed. Therefore, the majority of aircraft passengers with undiagnosed infectious TB are unlikely to be identified as infectious before boarding. Since it is difficult to determine whether a person may be medically unfit to travel, passengers with infectious TB are more likely to be identified after, rather than at the time of, a flight.

It is not justified to deny boarding systematically to all TB patients who are undergoing treatment. Most patients with drug-sensitive TB become non-infectious after two weeks of adequate treatment (20, 21). The responsible public health authority/physician involved should carry out a risk assessment including duration of treatment, clinical response, potential infectivity, potential drug resistance, and duration of the proposed flight. Patients infected with MDR-TB or XDR-TB will require a longer period of adequate treatment and detailed follow-up, with satisfactory clinical response to treatment, and sputum-culture conversion to negative before being confirmed as non-infectious and allowed to travel.

Physicians should inform all patients with infectious or potentially infectious TB that they pose a risk of infection for others, particularly those with whom they are in close contact for prolonged periods of time. Physicians should advise patients that they must not travel by any public air transportation, or by other public transportation, as long as they are considered infectious or potentially infectious according to the above criteria.

Patients being investigated for potentially infectious TB should follow the physician’s advice on whether to travel. Physicians should advise these patients not to plan to travel until the diagnosis and infectious status have been confirmed.

The physician and/or public health authority must give clear advice or instruction on whether travel may or may not be undertaken. Patients intending to travel against this advice should be reported to the appropriate public health authority for any necessary action to be taken, potentially together with the airline, in accordance with national legislation.

5.3. Precautions during travel

If during a flight a passenger is suspected of having infectious TB, because he or she informs the cabin crew or experiences severe symptoms such as haemoptysis, the cabin crew should try to relocate the passenger in an area without close contact with other passengers if space is available. One cabin-crew member should be designated to look after the ill passenger, preferably the crew member who has already been dealing with him/her. The ill passenger should be given a surgical face mask to prevent the dissemination of infectious droplets.1 If no mask is available or if the mask cannot be tolerated, the passenger should be given an adequate supply of paper tissues (or towels if necessary) and instructed to cover the nose and mouth at least when speaking, coughing or sneezing, and to dispose of the tissues appropriately.

Cabin crew should follow standard universal precautions when handling potentially infectious material (e.g. wear gloves, place disposables in a biohazard bag (if available) or in a sealed plastic bag, etc.) (30). The cabin-crew member designated to look after the possible index case may wear a surgical mask to protect against inhalation of infectious droplets, especially if the ill person cannot tolerate a mask. Cabin crew should receive routine training on the use of surgical masks. The IATA guidelines for suspected communicable disease in-flight, which have been approved by WHO, should always be followed by all airlines (31).

ICAO standards require the pilot in command to inform the air-traffic control provider that the aircraft may be carrying such a case; the IHR have similar requirements (see Annex 1). When advised, the air-traffic controller will transmit a message to the destination airport control tower, for onward transmission to the local public health authority. Timely communication provides an opportunity for the authority to prepare for arrival of the aircraft. It is important for States to develop a local procedure for reliably informing the health authority when notified of the imminent arrival of the aircraft concerned. (Other provisions of the IHR may also apply.)

Footnotes

1

Surgical masks retain and prevent the passage of infectious droplets but do not prevent the passage of aerosol suspensions of bacteria. They are therefore most effective when worn by the person who is the infectious source.