The number of asthma hospitalizations by age group (in multiples of the mean) in Canada graphed by the week of the year

Reproduced from: Johnston NW, Johnston SL, Norman GR, et al. The September epidemic of asthma hospitalization: School children as disease vectors. J Allergy Clin Immunol 2006; 117:557. Copyright © 2006. Illustration used with the permission of Elsevier Inc. All rights reserved.