3.1. Background
This chapter covers cleaning and disinfection procedures for both airports and aircraft.
Cleaning refers primarily to the removal of visible dirt or particles; however, the cleaning process and some products used for cleaning also result in disinfection. Cleaning is normally undertaken on a routine and frequent basis. In this chapter, the primary process of removal of visible dirt and particles is referred to as “cleaning”, even if some disinfection occurs at the same time.
Disinfection refers to specific measures taken to control, deactivate or kill infectious agents, such as viruses and bacteria. Disinfection is normally undertaken on an infrequent basis, during periodic maintenance checks or after a public health event, such as the suspected carriage of an infectious passenger. Disinfection is usually preceded by cleaning of the affected area, and this is assumed to occur when “disinfection” is referred to in this chapter.
In 2006, over 2 billion passengers were carried by airlines operating scheduled flights (ICAO, 2006). This fact indicates that commercial air transport is potentially an efficient means for spreading communicable disease widely by surface contact and proximity to infected persons.
Possible routes of infection transmission that might occur on board aircraft fall into three categories:
directly inhaled respiratory droplets, suspended airborne particles, or both;
direct contact with faecal matter, blood or other body fluids;
contact with respiratory secretions, faecal matter or body fluids deposited on surfaces or, for maintenance crews, entrained in ventilation systems.
The main source of infection for other travellers is from an infected person, and proximity to an infected person is an important risk factor for airborne infection. Once an infected person has left the scene, most of the risk from droplet exposure will have been removed. The residence time of suspended airborne particles may be longer and will depend on the particles' mass and on the ventilation rate/air circulation patterns in the cabin (ANSI/ASHRAE, 2008).
Airborne exposure aside, there is a concern that the agent of disease (pathogen) can remain in the airport or aircraft environment by contaminating common surfaces (e.g. fomites) after the infected traveller has departed. However, the guidance in this chapter is directed primarily at the second and third possible routes of transmission. The cause of illness for an individual traveller may not be known immediately and possibly not for some time afterwards; in many cases, the diagnosis may never be known. This guidance therefore adopts a “universal precaution” approach that treats all respiratory secretions, faeces, blood and other body fluids as potentially infectious.
Sometimes, a case of communicable disease is known only several days (or longer) after the infected person has travelled and may have deposited pathogens on surfaces in the airport or on the aircraft. The risk of infection upon contact with such contaminated surfaces will depend on the viability of the organism, the number of organisms, whether the surface has been properly cleaned and/or disinfected, whether the pathogen is touched and transferred and also the susceptibility of the traveller. Frequent hand washing reduces the risk. As time passes and as a result of routine cleaning activities, the risk that any transmissible pathogens remain in place reduces, even without specific disinfection procedures.
There may be epidemiological information available to guide the public health response, such as an outbreak occurring at the origin of the flight (e.g. the 2003 episode of SARS). In such instances, public health experts recommend specific measures targeted at a particular pathogen.
To reduce the risk of transfer of pathogens from an infected person to others via surfaces or inanimate objects on the aircraft or in the airport, it is necessary for aircraft and airport operators and ground handling agents to have a coordinated plan in place to deal with the arrival of an affected 1 aircraft having carried such a traveller or the presence of a person with a communicable disease in the airport. For aircraft, the plan needs to take into account the unusual features of the aircraft cabin in comparison with a ground-based facility. For airports, the plan should address the challenge of managing potential contamination in a large public space, such as the terminal building. Such plans should also address potential contamination of an aircraft or airport with an infectious agent that is not transmitted person to person. Considering that it may be difficult to identify an aircraft carrying an infected person, the focus should be on (a) the assumption that all aircraft are periodically occupied by infected travellers and therefore require routine and frequent cleaning and disinfection and (b) the fact that certain events (e.g. persistent coughing on board) may increase the risk of disease transmission and that such incidents should be investigated so that, if a case of communicable disease is suspected, it leads to specific disinfection measures.
Disinfectants tend to be oxidizers, and the interior of an aircraft contains many materials susceptible to damage from cleaning products and disinfectants. Metals used in the construction of the aircraft may corrode upon exposure to such products, safety-critical cables and wires may deteriorate on exposure and aircraft furnishings may have their fire resistance properties reduced. It is therefore necessary to exercise caution in selecting suitable products and before applying these products in aircraft. It is important to protect the health of the cleaning personnel and to ensure effective action; therefore, manufacturer's instructions must be followed carefully.
It is essential to provide a hygienic environment for travellers. Areas where food is prepared, stored and served, any surfaces commonly touched by people and washroom facilities, among others, should be kept free from contaminants that might compromise human health, even when there is no identified outbreak of disease. Prevention or mitigation of disease transmission is the goal. Hygienic conditions also minimize the likelihood of infestation by rodents, as vectors of disease.
3.1.1. International Health Regulations (2005)
According to the IHR (2005), States (competent authorities) must ensure, to the extent practicable, that traveller facilities at their international airports and on aircraft are kept free of sources of infection and contamination. In addition, capacity to adopt control measures, such as cleaning and disinfection, should be in place, with oversight by the competent authority, to prevent the spread of disease and its agents at airports and on aircraft.
If indications of a public health risk, including sources of infection and contamination, are found on board an international aircraft, the aircraft may be required to undergo health measures, such as disinfection, disinsection or decontamination, as appropriate, that are necessary to control risk and to prevent spread of disease (Article 27).
Health measures “shall be carried out so as to avoid injury and as far as possible discomfort to persons, or damage to the environment in a way which impacts on public health, or damage to baggage, cargo, containers, conveyances, goods or postal parcels” (Article 22) and “initiated and completed without delay, and applied in a transparent and non-discriminatory manner” (Article 42).
3.1.2. Critical aspects and rationale of cleaning and disinfection programmes
The critical aspects of cleaning and disinfection programmes include the availability of cleaning schedules and procedures for timely and effective airport and aircraft routine cleaning by designated personnel; procedures for disinfecting after an event; effective cleaning and disinfecting agents that are not detrimental to aircraft materials; appropriate personal protective equipment; and adequate training for designated personnel.
There are several reasons why cleaning and disinfection programmes are critical to ensuring a sanitary environment in airports and on aircraft, which, in turn, ensures that air travellers are exposed to minimum risk. Schedules and procedures for routine, effective airport and aircraft cleaning (and disinfection measures in higher-risk areas, when necessary) are vital in maintaining a hygienic environment. The availability of procedures for disinfecting after an event 2 is also critical, as body fluids, such as respiratory secretions, blood, vomit and faeces, may contain infectious agents that could be transmitted, if not properly contained.
Cleaning and disinfection on aircraft require special attention, as it is necessary to use agents that are not corrosive or otherwise detrimental to aircraft components. For this reason, not all effective cleaning and disinfecting agents can be used in the aircraft cabin.
Cleaning crews 3 need to be adequately trained so they understand and respect the procedures that will ensure effectiveness of the cleaning and disinfecting agents, use the proper personal protective equipment, prevent contamination of other areas and minimize occupational health and safety risks to personnel.
Unlike the routine procedure, post-event disinfection is not a frequent practice, and the requirements are likely to differ. It is therefore particularly important that the training emphasizes these “event-driven” procedures for the cleaning crew, because they will not be as familiar as routine cleaning procedures.
As noted above, competent authorities have responsibilities to ensure that international airports and aircraft are kept free of sources of infection and contamination (Article 22.1(a,b,c,d,e,g)). The competent authority needs to exercise oversight over cleaning and disinfection programmes so that its obligations under the IHR (2005) are fulfilled. Under the IHR (2005), the competent authorities are responsible for supervising service providers relating to travellers, baggage, cargo, containers, conveyances and goods at points of entry, including with inspections and medical examinations, as necessary. They are also responsible for supervision of disinfection, disinsection and decontamination of conveyances, as well as baggage, cargo, containers and goods under the IHR (2005). Finally, they are responsible for the supervision of the removal and safe disposal of any contaminated water or food, human or animal dejecta, wastewater and any other contaminated matter from a conveyance (Article 22.1(c,e–f)). In the context of conveyances (as well as baggage, cargo and goods) arriving from affected areas, the competent authorities are responsible for monitoring them so that they are free of sources of infection or contamination (Article 22.1(a)).
