Content of review 1, reviewed on June 07, 2020

This paper analyses the influence of city size on the COVID-19 attack rate using growth data from March 14th through March 19th from more than 160 US cities.

The reproductive numbers R of the disease depends on the infectious period (the time interval during which a host is infectious) and the contact rate (the number of social contacts that can transmit the disease per unit time). The paper argues that the infectious period is a physiological property that cannot be changed, and that the reproductive numbers R depends on the city size because in larger cities the contact rate is higher. According to the literature, the interactions in a city are tied to socioeconomic networks and have an average degree (number of social connections per capita) that increases approximately as a power law of city size. This paper finds empirical evidence of the scaling effect of city size in COVID-19 growth rate.

The authors conclude that larger cities are expected to require more aggressive strategies to control epidemics than smaller cities and those higher values of R result in a greater required vaccination rate in order to stop the outbreak.

Source

    © 2020 the Reviewer (CC BY 4.0).

References

    J., S. A., G., B. M., A., B. L. M. 2020. COVID-19 attack rate increases with city size. MedRxiv.