title: Hospitalization of pregnant women with pandemic A(H1N1) 2009 influenza in Canada.
abstract: This article describes the epidemiology of pandemic A(H1N1) 2009 influenza in all Canadian pregnant women admitted to hospital, and compares it with historical inter-pandemic influenza activity. We used weekly hospitalization and death counts of laboratory-confirmed pandemic A(H1N1) influenza cases reported to the Public Health Agency of Canada's (PHAC) 2009-2010 national pandemic influenza surveillance programme. Pregnant women infected and admitted with the pandemic strain were described and compared with: (1) confirmed admissions of all women of reproductive age; (2) all admitted cases reported to PHAC; and (3) to a historical average of inter-pandemic seasonal influenza admissions, and pneumonia and influenza (P&I) admissions for pregnant women. During the pandemic, 263 pregnant women with confirmed infections were admitted; four died in their third trimester. The median age for admitted pregnant cases was 27.5 years, which is consistent with the median age of the 3-year historical inter-pandemic pregnant comparison group. Aboriginal women appeared to be overrepresented but ethnicity was unavailable for 15.2% of all pregnant cases. Overall admission volumes were higher than those for seasonal influenza in the historical comparison group but were lower than those for P&I admissions. Despite increased admission volumes, severe outcomes in pregnant women were proportionally fewer than in all cases admitted for influenza A(H1N1) infection during the pandemic.
authors.affiliation: H1N1 Task Force, Centre for Immunization and Respiratory Infectious Diseases Public Health Agency of Canada, Ottawa, ON, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Rolland-Harris
authors.forename: J
authors.initials: J
authors.lastname: Vachon
authors.forename: R
authors.initials: R
authors.lastname: Kropp
authors.forename: J
authors.initials: J
authors.lastname: Frood
authors.forename: K
authors.initials: K
authors.lastname: Morris
authors.forename: L
authors.initials: L
authors.lastname: Pelletier
authors.forename: R
authors.initials: R
authors.lastname: Rodin
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002170:Canada / Q000453:epidemiology; D005006:Ethnicity; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000401:mortality / Q000821:virology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology* / Q000401:mortality / Q000821:virology*; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult