The study, conducted by Professor Thomas Plümper, looked into spatial contagion between local counties in England and found that cross district spatial contagion adds a very important amplifier to an already infectious disease.
As a result of the cross district spatial contagion, such as commuting, one additional individual per 100,000 is infected in other districts. This was shown to raise infections by a staggering total of 241 newly infected individuals per 100,000 people on average after seven weeks in the pre-lockdown period.
In contrast, if working from home was implemented earlier, the absence of spatial contagion would have meant that one additionally newly infected person, would only result in 72 newly infected individuals per 100,000 people by week seven.
“In other words, the high degree of spatial contagion during the pre-lockdown period roughly triples the number of cases. This is because in modern times, there is a faster and stronger spatial contagion than, for example, during the times of the plague. Mankind is more mobile and people travel longer distances at much higher speeds,” says Professor Plümper from the Department of Socioeconomics at WU.
However, the results also show that measures of social distancing not only managed to break the exponential growth of new infections within a region, but also drastically reduce the spread of the disease across local boarders.
For this reason, the researchers support a shift to local policies aimed at controlling the pandemic, which was successful in countries like Germany when the pandemic first hit.
They add that governments should move to decentralised control policies once the worst is over and weekly new infections have declined to low two-digit numbers per 100,000 people.
“We expect that decentralised, federal countries will find it easier to organise local control strategies, but one could hope that more centralised nation-states will eventually overcome the institutional disadvantages they face and also manage to successfully employ local strategies to keep the pandemic at bay,” says Professor Plumper.
The study was published in the journal Social Science and Medicine.