1 Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario, Canada.
2 Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States.
3 Division of Infectious Diseases, Children's Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, United States.
4 Department of Medicine, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
5 Department of Medicine and Centre for Quality Improvement and Patient Safety and University of Toronto, Toronto, Ontario, Canada.