Air travel is now widely accessible, with a resulting increase in the numbers of international air travellers and a consequently greater risk of communicable diseases being spread by infectious travellers. The transmission of airborne infections between people in confined spaces such as aircraft cabins is of particular concern to health officials and the general public. In the early 1990s, several reports concerning the transmission of tuberculosis (TB) infection including its then most dangerous form, multidrugresistant TB (MDR-TB), from infectious travellers to other passengers and crew during long flights, caused anxiety among travellers and serious concern among public health officials and airline companies. The World Health Organization (WHO) published guidelines in 1998 defining the extent of the problem and the potential risks, and providing recommendations for travellers, physicians, health authorities and airline companies.

The recommendations were based on the limited evidence available at the time:

investigations involving seven contagious TB patients and some 2600 potentially exposed air travellers. A second edition of the guidelines was published in 2006