Liu Lun's research group from the School of Government and Management revealed the law of the risk of new crown epidemic transmission in urban activity venues

Urbanization and population agglomeration bring substantial benefits to socio-economic development, but they also increase the risks of crowd gathering and interaction, such as the spread of infectious diseases, as exemplified by the pandemic
.
In the spread of urban infectious diseases, the spatial places that accommodate the activities of different groups of people are the key links connecting the physical environment, human activities and risk transmission, and it is of great significance
to understand the risk of infectious disease transmission in different spatial places for scientifically formulated urban infectious disease prevention and control plans and improve the resilience of urban infectious diseases.
However, in the study of the transmission law of the new crown epidemic, the systematic assessment of the risk of epidemic transmission in various urban spatial places is still relatively lacking
.

In response to this problem, the study took 906 urban areas with a certain population size or above in Japan, the United Kingdom, the United States, and Brazil as cases, and collected the event venue control policies implemented by the above-mentioned cities from March to August 2020 and the corresponding new crown epidemic transmission data, forming a multinational city-level epidemic prevention and control policy database, which was included in the Oxford New Crown Policy Data Platform (supertracker.
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。 On this basis, the study evaluates the risk of epidemic transmission in 11 types of people's activity places (including schools, offices, shopping places, catering venues, etc.
) and urban spaces of different scales and densities from the site scale and the urban scale
.
For the site scale, the double difference method was used to identify the impact of the opening and closing of the activity venues of the above 11 types of people on the epidemic transmission, which reflected the epidemic transmission risk
of these activity venues.
The study found that while the risk of transmission varied across countries across event venues, the risk of contagion was higher
overall in sports, entertainment and dining establishments.
The study also found that the proportion of epidemic transmission in the above-mentioned public activity places is higher in small and medium-sized cities, which can provide a reference
for formulating more efficient epidemic prevention and control policies.

For the city scale, the study extracted the fixed effect of epidemic transmission in all sample cities from the statistical model constructed in the previous step, and analyzed the correlation
between this fixed effect and the size, density and socioeconomic characteristics of the population.
The study found that the risk of city-scale transmission did not increase with city size and density, and this conclusion was valid
in all sample countries.
This finding challenges people's general perception that large-scale and high-density cities have a higher risk of epidemics, and has certain hints
for the formulation of national epidemic prevention and control strategies and even the planning of urban scale systems.

Changes in the opening and closing of activity venues for 11 types of people in all sample cities from March to August 2020

Impact of epidemic transmission in 11 types of crowd activity venues in cities of different sizes and densities

The findings, titled "Infectiousness of places – Impact of multiscale human activity places in the transmission of COVID-19," were published in the Nature series NPJ Urban (NPJ Urban).
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。 Liu Lun, assistant professor at Peking University's School of Government and researcher at the Institute of Public Governance, is the first author and corresponding author of the paper, and collaborators include researchers
from Tsinghua University, the Massachusetts Institute of Technology, the University of Florida, and the University of Cambridge.

This research work was supported by the National Natural Science Foundation of China, the National Social Science Foundation of China, and the Institute of Public Governance of Peking University, and was supported
by the High Performance Computing Platform of Peking University.