Using a mathematical model, the researchers managed to identify the areas most at risk from the point of view of the transmission of infectious diseases at Heathrow airport. A study that could be generalized to many other places.
This is a study that could help limit the transmission of infectious diseases. Of the scientists from Inserm, Sorbonne University and CSIC-IFISC modeled the places most at risk of contamination in an airport, a place where people stay for a long time and where a distance between individuals cannot always be respected.
Crowds and gatherings, with the resulting prolonged contact between individuals, are indeed a crucial factor in the transmission of viruses.
GPS data
An international team of researchers took the busiest airport in Europe as a model: Heathrow Airport in London. Between February and August 2017, so well before the outbreak of the Covid-19 pandemic, GPS data from the mobile phones of 200,000 travelers or employees was collected, which makes it possible to visualize the journeys of each of them in the airport.
They were then mathematically crossed with data concerning the spread of diseases such as the H1N1 flu or Covid-19. Thus, the areas where the risks of spreading viruses have been identified.
Restaurants, waiting rooms, shops…
According to the results of this study, it is not the places with the most mixed populations that are the most risky in terms of the spread of the virus. Conversely, it appears that it is rather a question of places where one remains motionless for a fairly long period.
“These places are not always the busiest within the airport, but they involve more sustained contact over longer periods between individuals, allowing diseases to be transmitted”, emphasizes Mattia Mazzoliresearcher at Inserm and first author of the study.
It is therefore not the corridors or the queues of the control areas but the bars, restaurants, shops or waiting rooms before boarding where there is a risk of catching a virus carried by another passenger in an airport. These areas represent only about 2% of the accessible surface of Heathrow airport.
Risk reduction
The models then made it possible to show that by targeting these areas most at risk with spatial immunization measures, that is to say by decontaminating them, we observe a 50% reduction in the risk of having a second case of H1N1 flu following a first case imported into the airport. This reduction is 40% for Covid-19.
“In the places we have identified with our model, developing dedicated approaches such as air filtering, systematic surface disinfection or the use of Far-UVC lamps can significantly reduce the risk of spreading agents. pathogens, beyond the first cases arriving at an airport or train station without being detected”, explains Mattia Mazzoli.
Generalizable model
If airports are particularly scrutinized, more than other crowded places, it is because they constitute a constant flow of entries and exits but, above all, because they can lead to the spread of an infectious disease at the level global.
However, as the scientists of this study explain, this mathematical model can be generalized and is applicable to other places of transit or crowd mixing.
It would thus be possible, for each case, to locate the areas at high risk of contamination. This model could therefore be particularly useful in the very early stages of an epidemic.
