Differential contagiousness of respiratory disease across the United States

The initial contagiousness of a communicable disease within a given population is quantified by the basic reproduction number, denoted R . The value of R gives the expected number of new cases generated by an infectious person in a wholly susceptible population and depends on both pathogen and population properties. On the basis of compartmental models that reproduce Coronavirus Disease 2019 (COVID-19) surveillance data, we estimated region-specific R values for 280 of 384 metropolitan statistical areas (MSAs) in the United States (US), which account for 95% of the US population living in urban areas and 82% of the total population. Our estimates range from 1.9 to 7.7 and quantify the relative susceptibilities of regional populations to spread of respiratory diseases. One-Sentence Summary Initial contagiousness of Coronavirus Disease 2019 varied over a 4-fold range across urban areas of the United States. LA-UR-22-29514 ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement We acknowledge support from the 2020 Mathematical Sciences Graduate Internship program sponsored by the Division of Mathematical Sciences of the National Science Foundation. We acknowledge support from the Center for Nonlinear Studies at Los Alamos National Laboratory. We acknowledge support from NIH/NIGMS grant R01GM111510. We acknowledge support from the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory. We are grateful for access to the FARM cluster at University of California, Davis. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study involves only openly available human data, which can be obtained from the GitHub repository maintained by The New York Times collecting Coronavirus (Covid-19) data in the United States (https://github.com/nytimes/covid-19-data). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript.