A Second Wave? What Do People Mean by COVID Waves? - A Working Definition of Epidemic Waves

Risk Manag Healthc Policy. 2021 Sep 13:14:3775-3782. doi: 10.2147/RMHP.S326051. eCollection 2021.

Authors

Stephen X Zhang¹, Francisco Arroyo Marioli², Renfei Gao³, Senhu Wang⁴

Affiliations

¹ Faculty of Professions, University of Adelaide, Adelaide, SA, Australia.
² Central Bank of Chile, Santiago, Chile.
³ Manchester Business School, University of Manchester, Manchester, UK.
⁴ Department of Sociology and the Centre for Family and Population Research, National University of Singapore, Singapore.

Abstract

Introduction: Policymakers and researchers describe the COVID-19 epidemics by waves without a common vocabulary on what constitutes an epidemic wave, either in terms of a working definition or operationalization, causing inconsistencies and confusions. A working definition and operationalization can be helpful to characterize and communicate about epidemics.

Methods: We propose a working definition of epidemic waves in the ongoing COVID-19 pandemic and an operationalization based on the public data of the effective reproduction number R.

Results: Our operationalization characterizes the numbers and durations of waves (upward and downward) in 179 countries.

Discussions: The proposed working definition of epidemic waves provides a common and consistent vocabulary that can enable healthcare organizations and policymakers to make better description and assessment of the COVID crisis to make more informed resource planning, mobilization, and allocation temporally in the continued COVID-19 pandemic.

Keywords: COVID wave; epidemic wave; epidemiology; infection; second wave.

Grants and funding

Dr Senhu Wang received funding from the Major Project of the National Social Science Fund of China (No. 19ZDA149) at Nanjing University, China and Assistant Professor Start-up Grant and Center for Family and Population Research Faculty Development Grant at the National University of Singapore.