Estimated Rates of Hospitalization, ICU Admission, and Mortality by Age and Risk Group for pH1N1 in Ontario, April to June 2009.

aHigh-risk conditions include one or more of: asthma, emphysema, chronic obstructive pulmonary disease, diabetes, heart disease, cancer, and stroke.
bDenominators were inflated 10-fold to account for expected underrepresentation of less severe pH1N1 cases among laboratory-confirmed cases.