Better air onboard reduces spread of disease on aircrafts

The spread of infectious diseases in-flight, can possibly be reduced by increasing ventilation within aircraft cabins, suggests a review published in this week’s issue of The Lancet.

Dr.Mark Gendreau (Lahey Clinic Medical Centre, MA, USA) and colleagues looked at data from studies into the transmission of diseases during commercial air travel and they found that although commercial airlines are a suitable environment for the spread of disease carried by passengers or crew, the environmental control systems used in commercial aircraft appear to restrict the spread of airborne diseases. Good ventilation in confined spaces reduces the concentration of airborne organisms, one air exchange can remove over 63% of airborne organisms suspended in a particular space. Data from an in-flight tuberculosis investigation has revealed that doubling ventilation rate in the cabin reduces infection risk by half and suggests that the risk of disease transmission to other symptom-free passengers within the aircraft cabin is restricted to sitting within two rows of a contagious passenger for a flight time of more than 8 h. This is also relevant to other airborne infectious diseases. However, in one outbreak of SARS, passengers as far as seven rows away from the source passenger were affected.

Disinsecting aircraft - spraying before landing to kill insects - and vector control around airports, as well as immunisation, seem to have been effective in non-endemic areas. International Health regulations recommend disinsecting aircraft travelling from countries with malaria and other vector-borne disease but only five countries currently do so (Australia, Caribbean, India, Kiribati, and Uruguay).

The team believe the aviation industry and medical community should employ an education strategy aimed at the general public on health issues related to air travel and infection. Even simple good hand hygiene has been proven to reduce the risk of disease transmission, and air travellers need to make it part of their normal travel routine.

Increased affordability and availability of air travel and mobility of people, make airborne, food-borne, vector-borne infectious diseases more common and more easily transmitted and is an important public health issue.Health officials have had to re-examine the potential of these agents because of increased fears of bioterrorism which could be spread by air travel. The SARS outbreak of 2002 showed how air travel can have an important role in the rapid spread of newly emerging infections and could potentially even start pandemics. In addition to flight crew, public health officials and health care professionals have an important role in the management of infectious diseases transmitted on airlines and should be familiar with guidelines provided by local and international authorities, says Dr Gendreau.