Restrictions in the movement of people have been a common response to the coronavirus pandemic, whether that’s on a national level or even on a regional level within countries.  With so many of us working remotely, this has in some cases resulted in an exodus of cities towards more rural areas, where space and access to nature make it somewhat easier and more comfortable to see out any lockdown measures.

New research explores what kind of impact this mobility may have had on the transmission of the virus.  The researchers focused specifically on the impact this movement from large cities to more rural areas may have had.

“Instead of taking mobility, or the lack of mobility, for granted, we decided to explore how an altered mobility would affect the spreading,” the researchers say. “The real answer lies in the sign of the result. People always assume that closing borders is good. We found that it is almost always bad.”

Urban exodus

The researchers developed a simple model to explore how migration patterns might affect the spread of disease, with a particular focus on population density.  The model suggests that attempts to limit the movement of people from high density to low density areas would actually be counter-productive, as the migration actually reduces the spread of disease.

The model involved a group of people in two locations, and assumed that their travel was largely random.  SIR, which stands for susceptible, infected, and recovered, dynamics was then used to track the spread of the disease through the interactions between people.

The simulation was run 10,000 times to try and gain a decent understanding of the way disease spreads between the two locations when migration was solely from the large city to the small town.  The results suggest that while the movement of people to small towns may slightly increase the risk for those in the small towns, it significantly reduces the risk for the population as a whole.

“Collaboration between different governments and administrations is an essential ingredient towards controlling a pandemic, and one should consider the possibility of small-scale sacrifices to reach a global benefit,” the researchers conclude.