There exists some ambiguity across jurisdictions and thus there is no clear universal case definition of COVID-19 hospitalization.
Public Health Ontario measures hospitalization as “the number of confirmed COVID-19 cases that reported ever being hospitalized during their infection”- i.e., all cases reported as ever being hospitalized during their infection.
The category “incidental COVID-19 hospitalizations” has been proposed. This refers to patients who are primarily admitted for other ailments and test positive as part of routine screening.
Some jurisdictions and health agencies have started differentiating between those who were admitted for COVID-19-related illness and incidental admissions. Ontario and Saskatchewan have begun using this category in their regular reporting of COVID-19 statistics.
New data from Australia, New Zealand, the US, and Canada indicate that 30 to 50 percent of COVID-19 hospitalizations are “incidental COVID-19 hospitalization” – 46% of COVID-19 hospitalizations in Ontario (as of January 11th, 2022) and 40% in Saskatchewan (as of January 26th, 2022)
Some expert opinions caution that such binary categorization may oversimplify clinical reality, and suggests also employing an ‘indeterminate’ category
Asamoah, G; Badea, A; Reeder, B; Groot, G; Muhajarine, N; Howell-Spooner, B; Young, C. What is the (case) definition of hospitalization for COVID-19 in similar jurisdictions? 2022 Feb 10. Document no.: CAC220101 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2022. 9 p. (CEST rapid review report).