Just “flattening the curve” is not enough, says Moritz Kraemer

Small, close-knit communities are at high risk for rapid, intense COVID outbreaks especially if they haven’t yet experienced outbreaks of COVID-19, shows a new study led by Branco Weiss Fellow Moritz Kraemer and co-authored by research teams at the University of Oxford and Boston’s Northeastern University.

The paper ”Crowding and the shape of COVID-19 epidemics”, published in Nature Medicine, shows that whether COVID outbreaks come to a fast, dramatic peak or whether they are long and drawn-out is more closely related to city layout and social structures than city size and density. Traditional epidemic models are based on a single population, but in reality, large cities are made up of many linked communities. This enables an outbreak to travel through city populations community-by-community resulting in a prolonged, sustained epidemic. “Public health measures are often focused on ‘flattening the curve’”, says Dr. Kraemer. “But this research shows that what that curve looks like will be very different from city to city, town to town, or even neighbourhood to neighbourhood. Measures should be developed with that perspective in mind.”

The researchers used highly spatially resolved daily epidemiological data from Chinese cities and Italian provinces, climate and population data, and the response to local interventions as measured by human mobility data. The paper includes a map of risk intensity covering 310 cities across the world showing those at risk of shorter, more overwhelming peaks, such as Novosibirsk, Russia and Ulaanbaatar, Mongolia, and those likely to have more extended outbreaks, including Madrid, Spain and Colombo, Sri Lanka.

Read the paper in Nature Medicine