title: Letter to the editor.
authors.affiliation: Vaccine Preventable Bacterial Diseases, National Microbiology Laboratory, Public Health Agency of Canada.
authors.forename: Raymond Sw
authors.initials: RS
authors.lastname: Tsang
authors.affiliation: Public Health Ontario Laboratory, Public Health Ontario, Faculty of Medicine, University of Toronto, Toronto, Ontario.
authors.forename: Frances B
authors.initials: FB
authors.lastname: Jamieson
authors.affiliation: Laboratoire de santé publique du Québec, Institut national de santé publique du Québec, Ste-Anne-de Bellevue.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Lefebvre
authors.affiliation: Institut national de santé publique du Québec, Centre de recherche du CHU de Québec, Laval University, Laval, Québec.
authors.forename: Rodica
authors.initials: R
authors.lastname: Gilca