Spread of disease no worse on planes

AIR PASSENGERS are no more at risk from contracting infectious diseases than people on the ground, a leading infectious disease specialist has said.

Despite the widely held belief that the enclosed cabin and poorer air quality on planes facilitate the transmission of diseases, Dr Paddy Mallon, consultant in infectious diseases at the Mater hospital, said the potential for spreading airborne pathogens on board a plane was no greater than in similar enclosed spaces on the ground.

Dr Mallon was commenting on the findings of a report by the European Centre for Disease Prevention and Control (ECDC) which found the incidence of diseases being spread via aircraft was “surprisingly low” considering the volume of air travel.

The ECDC’s Risk Assessment Guidelines for Infectious Diseases Transmitted on Aircraft report, published earlier this month, analysed the scientific data relating to the onboard transmission of 12 diseases, including influenza, severe acute respiratory syndrome (Sars), tuberculosis and measles.

It found that while there had been a number of cases of onboard transmission, the risk of contracting these diseases was no greater than in similar enclosed spaces on the ground, such as trains or offices.

The report noted that ventilation patterns on aircraft played a lesser role in disease transmission than was commonly thought and that the quality of air on board commercial airliners was often higher than in certain air-conditioned buildings.

Nevertheless, the study warned that there was a need to remain vigilant as passengers in a closed cabin environment can be exposed to infectious diseases afflicting fellow passengers.

It said the emergence of Sars in 2003 demonstrated the potential of a new disease to “suddenly appear and spread globally via air travel”.

When a public health risk is detected, the report recommended that the “contact tracing” of passengers who were exposed during a flight was an essential step towards containment. Dr Mallon said an individual’s susceptibility to contracting disease from another person, whether in an aircraft or on the ground, depended largely on how easily the disease itself transmitted.

Certain viruses, such as influenza, are produced in large amounts in the body during infection, so the potential to spread infection was greater than with some bacterial diseases where the “disease burden or load” was less, he said.

“With influenza, when we cough or sneeze, mucus particles carrying the disease get propelled about us, so the distance of contact is also an important factor.”