Contrary to current international guidelines, there is little risk of tuberculosis transmission linked to air travel, and tracing and screening air passengers and crew who might have been exposed to a person with tuberculosis is a highly inefficient resource-intensive process. Indeed, often limited resources would be better used by countries on other more effective aspects of tuberculosis control, according to a Review of the evidence published in the March edition of the Lancet Infectious Diseases.
Recent WHO guidelines recommend the tracing of airline passengers exposed to people with pulmonary tuberculosis who were seated in adjacent rows for longer than 8 hours, and that all commercial air travel should be prohibited until a person is no longer infectious. However, although tracing and screening is advocated in international guidelines, it is based on limited research about the risk of tuberculosis associated with air travel, and its true benefit is currently unknown.
Ibrahim Abubakar from the University of East Anglia, UK, who chaired the European Centre for Disease Prevention and Control (ECDC) working group on tuberculosis and air travel, reviewed the evidence from 39 studies looking at the transmission of tuberculosis during commercial air travel to determine if current international recommendations are justified. In total, 13 studies involving more than 4328 passengers from six countries were analysed.
The majority of studies found no evidence of tuberculosis transmission associated with air travel. Only two studies reported convincing evidence of transmission.
In total, 2761 passengers and crew were screened, yet only ten were found to have converted from a negative to a positive tuberculin skin reaction (with a high probability of progressing to active disease). Importantly, no cases of active tuberculosis resulting from transmission during air travel were reported.
The author comments: "Although an airline cabin is a closed confined space, the cumulative duration of exposure is relatively short compared with households or…other modes of transport where individuals might travel on the same route daily."
Additionally, the review points out that the difficulty of tracing air passengers, the complexity of contacting different national authorities, the poor response from passengers who are usually told that their risk is very low, and the cost of investigation, compared with the actual number of passengers with tuberculosis, makes the resource-intensive process highly inefficient.
Dr Abubakar concludes: "The burden of tuberculosis in many countries, including some middle-income countries, remains high. Many of these countries do not have the resources to investigate incidents of tuberculosis related to air travel…and resources might be better spent addressing other priorities of tuberculosis control and helping achieve all millennium development goals related to tuberculosis."
Dr Ibrahim Abubakar, University of East Anglia, Norwich, UK. T) +44 (0)1603 593 496 E) i.abubakar@uea.ac.uk
For full Review, see: http://press.thelancet.com/airtravel.pdf
Journal
The Lancet Infectious Diseases