title: Determining rubella immunity in pregnant Alberta women 2009-2012.
abstract: Rubella IgG levels for 157,763 pregnant women residing in Alberta between 2009 and 2012 were analyzed. As there have been no reported cases of indigenous rubella infection in Canada since 2005, there has been a lack of naturally acquired immunity, and the current prenatal population depends almost entirely on vaccine induced immunity for protection. Rubella antibody levels are significantly lower in younger maternal cohorts with 16.8% of those born prior to universal vaccination programs (1971-1980), and 33.8% of those born after (1981-1990) having IgG levels that are not considered protective (<15 IU/mL). Analysis across pregnancies showed only 35.0% of women responded with a 4-fold increase in antibody levels following post-natal vaccination. Additionally, 41.2% of women with antibody levels <15 IU/mL had previously received 2 doses of rubella containing vaccine. These discordant interpretations generate a great deal of confusion for laboratorians and physicians alike, and result in significant patient follow-up by Public Health teams. To assess the current antibody levels in the prenatal population, latent class modeling was employed to generate a two class fit model representing women with an antibody response to rubella, and women without an antibody response. The declining level of vaccine-induced antibodies in our population is disconcerting, and a combined approach from the laboratory and Public Health may be required to provide appropriate follow up for women who are truly susceptible to rubella infection.
authors.affiliation: Surveillance and Assessment, Alberta Ministry of Health, Edmonton, AB, Canada.
authors.forename: Florence Y
authors.initials: FY
authors.lastname: Lai
authors.affiliation: Surveillance and Assessment, Alberta Ministry of Health, Edmonton, AB, Canada.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Dover
authors.affiliation: Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
authors.forename: Bonita
authors.initials: B
authors.lastname: Lee
authors.affiliation: Department of Microbiology, Immunology & Infectious Diseases (MIID), University of Calgary, Calgary, AB, Canada; Provincial Laboratory for Public Health (ProvLab), Calgary, AB, Canada.
authors.forename: Kevin
authors.initials: K
authors.lastname: Fonseca
authors.affiliation: DynaLIFEDX Diagnostic Laboratory Services, Edmonton, AB, Canada; Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Natalia
authors.initials: N
authors.lastname: Solomon
authors.affiliation: Public Health Agency of Canada, Ottawa, ON, Canada.
authors.forename: Sabrina S
authors.initials: SS
authors.lastname: Plitt
authors.affiliation: Communicable Disease Control, Alberta Health Services, Edmonton, AB, Canada.
authors.forename: Joy
authors.initials: J
authors.lastname: Jaipaul
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Calgary, AB, Canada; Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Graham A
authors.initials: GA
authors.lastname: Tipples
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Calgary, AB, Canada; Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada. Electronic address: Carmen.Charlton@albertahealthservices.ca.
authors.forename: Carmen L
authors.initials: CL
authors.lastname: Charlton
mesh_terms: D000328:Adult; D000416:Alberta / Q000453:epidemiology; D000914:Antibodies, Viral / Q000097:blood*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control; D011295:Prenatal Care; D011296:Prenatal Diagnosis; D012409:Rubella / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G
keywords: Prenatal screening; Rubella; Total IgG antibody levels