FIGURE 1.

Study cohorts and exclusions. (A) Influenza hospitalization cohort. (B) RSV hospitalization cohort. (C) SARS‐CoV‐2 hospitalization cohort. Exclusions were made in the order in which they appear. RSV, respiratory syncytial virus; SARS‐CoV‐2, severe acute respiratory syndrome coronavirus 2; OHIP, Ontario health insurance plan. ^†Influenza and RSV hospitalizations prior to the 2010–11 respiratory virus season were excluded to reduce selection bias due to changes in testing behavior following the H1N1 influenza epidemic in 2009–2010. ^‡Virus seasonality was defined as November through May, and November through April for influenza and RSV, respectively