title: Low pertussis toxin antibody levels in two regional cohorts of Canadian pregnant women.
abstract: Infants under 6 months of age are at greatest risk of mortality and severe morbidity from pertussis disease. Interventions that increase pertussis protection in newborns are therefore a clear public health imperative. The objective of this study was to assess maternal pertussis toxin antibody (anti-PT) level as a potential source of mother-to-child transfer of pertussis-associated antibodies that may reduce neonatal risk of pertussis disease. Anti-PT level was assessed in a 2013 cohort of pregnant women from two regions in two Canadian provinces, British Columbia and Nova Scotia. Basic demographics, health, and pertussis immunization history were collected, along with blood specimens. Anti-PT levels were compared for self-reported vaccination status and prior pertussis disease. To assess secular trend, a parallel analysis was also undertaken, using anonymized residual sera from a 1996-1997 cohort of pregnant women in British Columbia. A total of 169 pregnant women participated in the study - 50 from Nova Scotia and 119 from British Columbia. The mean and median age of participants from both sites was 31 years of age (range 16-42 years). The lower limit of quantification of the anti-PT assay was 10 ELISA units per milliliter (EU/ml). Overall, 59% of women had anti-PT levels less than 10 EU/ml and anti-PT level did not differ with time since last self-reported pertussis vaccination (χ(2)(2)=3.166, p=0.205). Among a 1996-1997 cohort of pregnant women in British Columbia, 101 of 200 (51%) had anti-PT levels less than 10 EU/ml. Our study found that most pregnant women in two geographically disparate health regions in Canada have low residual anti-PT levels, may be vulnerable to pertussis infection themselves, and would unlikely be a source of passive ante- or postnatal transfer of anti-PT to their newborn.
authors.affiliation: Fraser Health Authority, Office of the Chief Medical Health Officer, #400 - 13450 102 Ave, Surrey, British Columbia, Canada V3T 0H1. Electronic address: mark.bigham@fraserhealth.ca.
authors.forename: Mark
authors.initials: M
authors.lastname: Bigham
authors.affiliation: Fraser Health Authority, Office of the Chief Medical Health Officer, #400 - 13450 102 Ave, Surrey, British Columbia, Canada V3T 0H1.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Konrad
authors.affiliation: Fraser Health Authority, Office of the Chief Medical Health Officer, #400 - 13450 102 Ave, Surrey, British Columbia, Canada V3T 0H1.
authors.forename: Paul
authors.initials: P
authors.lastname: Van Buynder
authors.affiliation: Fraser Health Authority, Office of the Chief Medical Health Officer, #400 - 13450 102 Ave, Surrey, British Columbia, Canada V3T 0H1.
authors.forename: Jan
authors.initials: J
authors.lastname: Van Buynder
authors.affiliation: British Columbia Public Health and Microbiology Reference Laboratory, British Columbia Centre for Disease Control, 655 West 12th Ave, Vancouver, British Columbia, Canada V5Z 4R4.
authors.forename: Judy
authors.initials: J
authors.lastname: Isaac-Renton
authors.affiliation: Canadian Center for Vaccinology, Dalhousie University, Capital Health and the IWK Health Centre, Goldbloom RCC Pavilion, 4th Floor, 5850/5980 University Ave, Halifax, Nova Scotia, Canada B3K 6R8.
authors.forename: May
authors.initials: M
authors.lastname: ElSherif
authors.affiliation: Canadian Center for Vaccinology, Dalhousie University, Capital Health and the IWK Health Centre, Goldbloom RCC Pavilion, 4th Floor, 5850/5980 University Ave, Halifax, Nova Scotia, Canada B3K 6R8.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Halperin
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D001955:British Columbia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007112:Immunity, Maternally-Acquired; D009674:Nova Scotia / Q000453:epidemiology; D037342:Pertussis Toxin / Q000276:immunology*; D011247:Pregnancy; D016036:Seroepidemiologic Studies; D014917:Whooping Cough / Q000453:epidemiology* / Q000517:prevention & control; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D037342:Pertussis Toxin
keywords: Canada; Pertussis toxin antibody; Pregnant women