The coronavirus has the Netherlands in its grip. We are trying to stop the epidemic by keeping one and a half metres apart and following separate walking routes in stores and offices. But how effective are these measures in indoor spaces?
“The National Institute for Public Health and the Environment uses scientific models to chart the spread of the coronavirus in the whole of the Netherlands and specific regions,” explains infectious disease epidemiologist Quirine ten Bosch. “However, the measures also have an influence at much smaller scales: can you go to the movies or dine out at your favourite restaurant? We want to know exactly what happens in indoor spaces and how the behaviour of people indoors influences the spread of corona, including when the measures are less strictly observed. With this information, you can design measures that enable people to do as much as possible while still staying safe.”
TU Delft's crowd monitoring system
Epidemiologists of the Quantitative Veterinary Epidemiology chair group are collaborating with partners from TU Delft’s ActiveModeLab to track interactions between people with a crowd monitoring system. To this end, the TU Delft canteen has been equipped with sensors and cameras that monitor how many people are in the room and how much distance they keep from each other. “We link this data to a transmission model that simulates the spread of the coronavirus in a room,” says Ten Bosch. “The model takes account of various factors such as the quantity of virus particles left on a table or virus droplets in the air.”
The epidemiologists are aware that not everyone always keeps a distance of one and a half metres from others, while in terms of the contamination risk it probably makes a big difference whether you keep one metre or one and a half metres apart. “We have not monitored in restaurants yet, but we expect that if people comply with the measures they will not walk around much in restaurants and so they will have prolonged contact with relatively few people. They will therefore face only a small risk of contamination, although this will vary greatly depending on the setting.”
Corona tool for restaurants
Quirine ten Bosch ultimately hopes to be able to provide restaurant owners, store owners or managers of concert halls with more insight into measures they can take to further reduce the risk of infection. For this purpose, the Quantitative Veterinary Epidemiology chair group is developing a tool called "SamenSlimOpen" (OpenSmartTogether) which will initially only be for restaurant owners. The owners can see how the risk of contamination will change if, for example, they spread the tables further apart or have customers dine during time slots of at most an hour and a half. “We expect the risk of contamination in restaurants to be relatively low, especially if owners use the tool. However, at the national level, the number of infections in restaurants does make a difference, because thousands of people go out to dine.”
The government can use the research results to determine their policy, and restaurant owners can use the tool to make their restaurants as corona-proof as possible. “Ultimately, we want to make the tool usable for stores, offices and large concert halls, so that we will soon all be able to do more in a safe manner.”