title: Pertactin-negative Bordetella pertussis strains: evidence for a possible selective advantage.
abstract: BACKGROUND
  A recent increase in Bordetella pertussis without the pertactin protein, an acellular vaccine immunogen, has been reported in the United States. Determining whether pertactin-deficient (PRN(-)) B. pertussis is evading vaccine-induced immunity or altering the severity of illness is needed.
  
  
  METHODS
  We retrospectively assessed for associations between pertactin production and both clinical presentation and vaccine history. Cases with isolates collected between May 2011 and February 2013 from 8 states were included. We calculated unadjusted and adjusted odds ratios (ORs) using multivariable logistic regression analysis.
  
  
  RESULTS
  Among 753 isolates, 640 (85%) were PRN(-). The age distribution differed between cases caused by PRN(-) B. pertussis and cases caused by B. pertussis producing pertactin (PRN(+)) (P = .01). The proportion reporting individual pertussis symptoms was similar between the 2 groups, except a higher proportion of PRN(+) case-patients reported apnea (P = .005). Twenty-two case-patients were hospitalized; 6% in the PRN(+) group compared to 3% in the PRN(-) group (P = .11). Case-patients having received at least 1 pertussis vaccine dose had a higher odds of having PRN(-) B. pertussis compared with unvaccinated case-patients (adjusted OR = 2.2; 95% confidence interval [CI], 1.3-4.0). When restricted to case-patients at least 1 year of age and those age-appropriately vaccinated, the adjusted OR increased to 2.7 (95% CI, 1.2-6.1).
  
  
  CONCLUSIONS
  The significant association between vaccination and isolate pertactin production suggests that the likelihood of having reported disease caused by PRN(-) compared with PRN(+) strains is greater in vaccinated persons. Additional studies are needed to assess whether vaccine effectiveness is diminished against PRN(-) strains.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Stacey W
authors.initials: SW
authors.lastname: Martin
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Lucia
authors.initials: L
authors.lastname: Pawloski
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Margaret
authors.initials: M
authors.lastname: Williams
authors.affiliation: Vermont Department of Health, Burlington.
authors.forename: Keeley
authors.initials: K
authors.lastname: Weening
authors.affiliation: Washington State Department of Health, Seattle.
authors.forename: Chas
authors.initials: C
authors.lastname: DeBolt
authors.affiliation: Seattle Children's Hospital, Seattle, Washington.
authors.forename: Xuan
authors.initials: X
authors.lastname: Qin
authors.affiliation: Multnomah County Health Department, Portland, Oregon.
authors.forename: Laura
authors.initials: L
authors.lastname: Reynolds
authors.affiliation: Minnesota Department of Health, St. Paul.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Kenyon
authors.affiliation: New York State Department of Health, Albany.
authors.forename: Gregory
authors.initials: G
authors.lastname: Giambrone
authors.affiliation: Connecticut Department of Health, Hartford.
authors.forename: Kathy
authors.initials: K
authors.lastname: Kudish
authors.affiliation: Colorado Department of Health and Environment, Denver.
authors.forename: Lisa
authors.initials: L
authors.lastname: Miller
authors.affiliation: New Mexico Department of Health, Santa Fe.
authors.forename: David
authors.initials: D
authors.lastname: Selvage
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Adria
authors.initials: A
authors.lastname: Lee
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Tami H
authors.initials: TH
authors.lastname: Skoff
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Hajime
authors.initials: H
authors.lastname: Kamiya
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Cassiday
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Tondella
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Clark
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis* / Q000235:genetics* / Q000276:immunology; D015153:Blotting, Western; D001886:Bordetella pertussis / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D057131:Immune Evasion; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010567:Pertussis Vaccine / Q000008:administration & dosage*; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D010566:Virulence Factors, Bordetella / Q000032:analysis* / Q000235:genetics* / Q000276:immunology; D014917:Whooping Cough / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D055815:Young Adult
chemical_list: D001425:Bacterial Outer Membrane Proteins; D010567:Pertussis Vaccine; D010566:Virulence Factors, Bordetella; C068929:pertactin
keywords: Bordetella pertussis; acellular vaccine; mutations; pertactin; waning immunity