1 Department of Medicine, St Joseph's Healthcare Hamilton, Hamilton, Ontario, ON, Canada; McMaster University, Hamilton, ON L8S 4K1, Canada. Electronic address: chudk@mcmaster.ca.
2 Division of Allergy & Immunology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
3 Department of Medicine, St Joseph's Healthcare Hamilton, Hamilton, Ontario, ON, Canada; Department of Pediatrics, St Joseph's Healthcare Hamilton, Hamilton, Ontario, ON, Canada; McMaster University, Hamilton, ON L8S 4K1, Canada.
4 Allergy Division, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy.
5 Department of Medicine, St Joseph's Healthcare Hamilton, Hamilton, Ontario, ON, Canada; McMaster University, Hamilton, ON L8S 4K1, Canada.
6 Department of Medicine, St Joseph's Healthcare Hamilton, Hamilton, Ontario, ON, Canada; Department of Health Research Methods, Evidence and Impact, St Joseph's Healthcare Hamilton, Hamilton, Ontario, ON, Canada; McMaster University, Hamilton, ON L8S 4K1, Canada; Michael G DeGroote Cochrane Canada Centre, Hamilton, ON, Canada.