Airports: what are the areas most at risk of infectious disease transmission?

Using a mathematical model, scientists from Inserm, Sorbonne University and CSIC-IFISC have succeeded in defining the areas most at risk of contamination in airports. The results of this study could help reduce the transmission of infectious diseases between travellers.

Reduce the risk of transmission

To carry out this study, the researchers chose a place with a high population density: Heathrow airport in London, the busiest in Europe. Subsequently, they developed a mathematical model built from anonymous GPS data from more than 200,000 individuals. These data come from the geolocation of their mobile phone between February and August 2017.

Thus, the scientists were able to visualize the routes taken by these people in the airport and detect the places of the most intense contact. They then cross-referenced this information with data on the spread of the H1N1 flu virus and Covid-19.

Bars and restaurants: the areas most at risk?

According to the results of the models, it is not the corridors, the counters or even the baggage control areas which are the most risky places. Bars and restaurants, common areas that “connect travelers and airport workers who are in the same place for long periods of time”, are the riskiest, say the researchers. Shops and waiting rooms before boarding are also places at high risk of disease transmission.

“The danger of these contagion zones results from the balance between the number of people who pass through them and the length of their stay. These places are not always the busiest within the airport, but they involve more contact sustained over longer periods of time between individuals, allowing diseases to be transmitted”adds the lead author of the study.

These areas represent only about 2% of the accessible surface of Heathrow airport. Scientists have also discovered that by decontaminating these spaces (air filtering, systematic disinfection of surfaces or the use of Far-UVC lamps), “we observe a 50% reduction in the risk of having a secondary case of H1N1 following a first case imported into the airport. This reduction is 40% for Covid-19”.

A generalized model to study future pathogens

As the researchers point out, this mathematical model could be generalized to other places of high population concentration such as stations, metros, trains, shopping centers or even conference halls. This would also allow, in the future, to study other uncategorized pathogens.

“The implementation of spatial immunization measures reduces the number of infections among airport users and, to a lesser extent, among airport workers. Well targeted and implemented in places identified as most at risk, these measures would contain and/or delay the spread of infectious agents to the rest of the world via airports and other centers of affluence.Our model could be particularly useful in the early stages of a possible future epidemic, while the first cases imported into airports and train stations have not yet been detected”, concludes Mattia Mazzoli.