RT Journal Article SR Electronic T1 Canada needs a national immunization program: an open letter to the Honourable Anne McLellan, federal minister of health JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 567 OP 568 VO 168 IS 5 A1 Monika Naus A1 David W. Scheifele YR 2003 UL http://www.cmaj.ca/content/168/5/567.abstract