A review of the evidence published in the March edition of The Lancet Infectious Diseases reports that there is little risk of tuberculosis transmission linked to air travel. This is contrary to current international guidelines. In addition, tracing and screening air passengers and crew who might have been exposed to a person with tuberculosis is a highly inefficient resource-intensive process. In fact, in some cases limited resources would be better used by countries on other more effective aspects of tuberculosis control.
The latest World Health Organization (WHO) guidelines recommend the tracing of airline passengers exposed to people with pulmonary tuberculosis who were seated in nearby rows for longer than eight hours. In addition, all commercial air travel should be prohibited until a person is no longer infectious. Tracing and screening is advocated in international guidelines. However, it is based on limited research about the risk of tuberculosis associated with air travel. Also, the true benefit is currently unknown.
Ibrahim Abubakar, University of East Anglia, UK, chaired the European Centre for Disease Prevention and Control (ECDC) working group on tuberculosis and air travel. He reviewed the evidence from thirty nine studies looking at the transmission of tuberculosis during commercial air travel to verify if current international recommendations are justified. In total, thirteen studies involving more than 4,328 passengers from six countries were analyzed.
Only two studies reported realistic evidence of transmission. The majority of studies found no evidence of tuberculosis transmission associated with air travel.
In total, 2,761 passengers and crew were screened. 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. Significantly, there were no reports of cases of active tuberculosis resulting from transmission during air travel.
The author remarks: “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.”
Moreover, the review indicates that compared with the actual number of passengers with tuberculosis, the resource-intensive process is highly inefficient because of:
• 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
• the cost of investigation
Dr Abubakar writes in conclusion: “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.”
“Tuberculosis and air travel: a systematic review and analysis of policy”
Lancet Infect Dis 2010; 10: 176-83
Written by Stephanie Brunner (B.A.)