A new and super-interesting study was published in Nature this week examining the relative risk of SARS CoV2 virus spread in various environments like restaurants and bars, gyms, grocery stores and a host of other environments.
The researchers used a model that integrates fine-grained, dynamic mobility networks to simulate the spread of SARS-CoV-2 in 10 of the largest US metropolitan statistical areas. They used cell phone data to map the hourly movements of 98 million people from neighborhoods to evaluate the relative contribution to viral spread from places like restaurants and bars, gyms, retail stores, churches, and other places. They developed a model that accurately fits the real case COVID-19 trajectory.
Just as other research has shown, their model predicts that a small minority of “super-spreader” places account for a large majority of infections. Restaurants and bars were far and away the riskiest environments. Gyms were a distant second with 4x less risk than restaurants and bars.
They conclude that interventions like restricting maximum occupancy at restaurants and bars is a more effective intervention than uniformly reducing mobility (e.g. a broad-based stay at home order):
“This highlights the non-linearity of predicted infections as a function of visits: one can achieve a disproportionately large reduction in infections with a small reduction in visits. Reopening full-service restaurants has the largest predicted impact on infections, due to the large number of restaurants as well as their high visit densities and long dwell times.”
Important information to take into consideration as we again enter exponential amplification of the virus and diminishing hospital capacity.