Reducing the transmission of infectious diseases at airports

Transport hubs such as airports play a major role in the spread of transmissible diseases. Now, a project called PANDHUB is looking at ways of reducing that risk and managing high-threat endemics. Project coordinator Ilpo Kulmala talks to Eva Grey about lessons learned so far, and what airports can do to keep their staff and passengers safe from dangerous diseases.

Launched in November 2014, the European Union-funded PANDHUB research project saw a team of scientists join forces to tackle the spread of high-threat diseases in transport hubs across the world.

Air travel is regarded as a particularly conductive environment for air-borne diseases or illnesses transmitted by direct physical contact, while high-density airports visited by millions of passengers a day can accelerate the spread of infectious diseases.

Illnesses such as measles, tuberculosis and influenza, transmitted by coughing, sneezing or contact with contaminated surfaces, pose a particular threat.

Global transmission

Past international health crises such as the SARS outbreak of 2003, which spread to 37 countries and caused about 1,000 deaths, and the H1N1 swine flu virus in 2009 which killed about 300,000 people worldwide, show just how quickly such afflictions can spread if they are not quickly contained.

According to data from the project, in 2014 there were 3.3 million flights around the world, 44% of which were long haul. International Air Transport Association (IATA) figures show that last year, 3.5 billion people flew around the world, with that number forecast to double over the next 15 years.

Due to globalisation, growing populations and the increased accessibility and ubiquity of air travel, airports now need to have a strong prevention mechanism in place and a solid response plan in the event of a pandemic.

The EU invested €3.1m into the three-year research project, the aim of which is to assess threats, forecast, and to model and develop an action plan in the event of a crisis. The results are expected to be released in October 2017.

Five participant bodies – Public Health England and the University of Nottingham from the UK, Assistance Publique and MEDES from France and the University of Eastern Finland – have been working under the coordination of the VTT Technical Research Centre of Finland.

The outcomes will also be shared with institutions including the European Centre for Disease Prevention and Control (ECDC), the World Health Organization (WHO) and transport hub operators in an effort to create a safer, healthier environment for passengers and staff alike.

Eva Grey: How did the idea behind PANDHUB come about, and why is this study necessary?

Ilpo Kulmala: PANDHUB is a security-themed project funded under the Seventh Framework Programme of the EU. In the rapidly changing world, new threats may emerge quickly, and to prepare for them we need to understand the threats more deeply.

Therefore, our consortium comprising of public health experts, infectious disease specialists, health emergency managers, microbiologists, epidemiologists and contamination control specialists decided to apply for the [EU] grant.

EG: Why would you say airports are high risk?

IK: In all transport hubs, like ground transport, there is an increased risk for disease transmission from infectious individuals to susceptible persons, due to high passenger densities in confined spaces and numerous frequently touched surfaces.

Our investigation identified these hot spots, which are points or sites within a traffic hub environment where the risk for microbial transmission is at least periodically increased due to favourable conditions or human behaviour.

Moreover, airports are unique because there is the mixing of people from around the world with different population immunity and endemic diseases.

EG: The project has been running since November 2014. What has been achieved so far?

IK: One achievement was the creation of scenarios and selection of scenario agents which will be used in the later work, which is currently classified.

Our scenario agents include naturally occurring diseases, such as pandemic influenza and Ebola, as well as agents which may be spread intentionally. They are selected so that they cover as widely as possible different disease transmission routes.

We will investigate how a transport hub environment aids disease spread and what strategies can be implemented at transport hubs to help mitigate disease spread.

Disease surveillance tools have been reviewed and while some surveillance systems have relevance to transport hub incidents, none are specifically linked to transport hubs, or can be certain of picking such signals up quickly.

Therefore the proposed enhancement is to use more than one system and integrating data sources together to likely increase detection of events in transport hubs. One possibility could be the combination of Emergency Department systems with telephone help-lines.

Out of the reviewed microbial detection and identification methods, a DNA-based method seems to be the most interesting alternative for detection of specific high-threat pathogens.

An important phase in the pathogen detection or identification is the sampling: where to sample to get a representative result? Here the work done will give insight to the selection of appropriate sampling points.

The communication flows in case of high-threat pathogen incidents have also been reviewed. This looked at the communication flows in case of a serious health incident at international, EU and national level. This work serves as background information in the development of the communication tools, as well as the epidemiological data collection tool.

Lastly, an IT tool utilising mobile technology has been developed for data collection in case of pandemics.

EG: Considering that the number of airline passengers is forecast to double in the next 15 years, do you think the risks are growing?

IK: It is likely that diseases will spread around the world quicker due to increased air travel.

Airports are possible places where the infectious individuals may interact with airport staff and other passengers. The risk for disease transmission will depend on several factors like the disease transmission mode and infectivity of the disease, as well as vaccination status and duration of exposure, and possible protective measures.

It may thus be difficult to say for sure whether the risk for disease transmission will increase, but perhaps that the possibilities for this will increase.

EG: What new information do you expect to come out of PANDHUB, and how will it be used by airports?

IK: The study will give us more detailed information about how different diseases are transmitted in transport environments, what actions will need to be taken to prepare for and respond to high-threat pathogen incidents.

Moreover, we asked what some effective counter-measures for different diseases are, and how contaminated areas can be cleaned quickly and efficiently.

Airport staff will hopefully take the results into consideration in their preparedness and response planning. Airports can also find useful measures that organisations and individuals can undertake to reduce disease transmission risk.

EG: What can airports do now to keep staff and passengers safe from dangerous diseases?

IK: Personal behaviour is one important factor: in case of respiratory diseases coughing etiquette (cover your cough and sneezes, do not spread your respiratory droplets over other passengers), hand hygiene, no face touch (several diseases can spread indirectly first by touching contaminated surfaces and then eyes, mouth or nose), maintain separation (over 1m) between persons.

Organisational measures can be applied to reduce congestion, and perhaps mixing of transfer passengers from regions where dangerous diseases prevail.

For airborne diseases sufficient ventilation and air cleaning is important. Enhanced surface cleaning may be necessary to reduce transmission of certain diseases. Personal protection may be needed for some diseases.