title: Maternal immune response and neonatal seroprotection from a single dose of a monovalent nonadjuvanted 2009 influenza A(H1N1) vaccine: a single-group trial.
abstract: BACKGROUND
  Pregnant women and infants who get influenza are at increased risk for severe illness.
  
  
  OBJECTIVE
  To evaluate the immunogenicity and transplacental antibody transfer of 2009 pandemic influenza A(H1N1) vaccine administered during pregnancy.
  
  
  METHODS
  Prospective, multicenter, single-group clinical trial. (ClinicalTrials.gov registration number: NCT01024400)
  
  
  METHODS
  Five level-3 perinatal centers in France.
  
  
  METHODS
  107 pregnant women between 22(0/7) and 32(0/7) weeks of gestation.
  
  
  METHODS
  An intramuscular dose of a nonadjuvanted H1N1 vaccine that contained 15 mcg of hemagglutinin.
  
  
  METHODS
  Proportion of women with an influenza antibody titer of 1:40 or greater at days 21 and 42 after vaccination, delivery, and 3 months after delivery. Seroconversion rate, fold increase in the geometric mean titer 21 days after vaccination, and proportion of neonates with an antibody titer of 1:40 or greater at birth were also assessed.
  
  
  RESULTS
  At baseline, 19% of the women had an antibody titer of 1:40 or greater. At day 21, 98% of the women had an antibody titer of 1:40 or greater, the seroconversion rate was 93%, and the fold increase in geometric mean titer was 67.4. At day 42, delivery, and 3 months after delivery, 98%, 92%, and 90% of the women, respectively, had an antibody titer of 1:40 or greater. Ninety-five percent of the cord serum samples obtained from 88 neonates showed an antibody titer of 1:40 or greater. The median neonate-mother antibody titer ratio was 1.4.
  
  
  CONCLUSIONS
  Only healthy pregnant women were selected. Data on hemagglutination inhibition antibody titers of infants were reported only at birth.
  
  
  CONCLUSIONS
  A single dose of a nonadjuvanted influenza A(H1N1) vaccine with 15 mcg of hemagglutinin triggered a strong immune response in pregnant women and a high rate of neonatal seroprotection.
  
  
  BACKGROUND
  French National Institute of Health and Medical Research.
authors.affiliation: Université Paris Descartes, Paris, France.
authors.forename: Vassilis
authors.initials: V
authors.lastname: Tsatsaris
authors.forename: Catherine
authors.initials: C
authors.lastname: Capitant
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz
authors.forename: Corine
authors.initials: C
authors.lastname: Chazallon
authors.forename: Sophie
authors.initials: S
authors.lastname: Bulifon
authors.forename: Didier
authors.initials: D
authors.lastname: Riethmuller
authors.forename: Olivier
authors.initials: O
authors.lastname: Picone
authors.forename: Patrice
authors.initials: P
authors.lastname: Poulain
authors.forename: Fanny
authors.initials: F
authors.lastname: Lewin
authors.forename: Fabrice
authors.initials: F
authors.lastname: Lainé
authors.forename: Evelyne
authors.initials: E
authors.lastname: Jacqz-Aigrain
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Aboulker
authors.forename: Odile
authors.initials: O
authors.lastname: Launay
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D007251:Influenza, Human / Q000517:prevention & control*; D008431:Maternal-Fetal Exchange; D008875:Middle Aged; D009500:Neutralization Tests; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control*; D011262:Pregnancy Trimester, Second / Q000276:immunology; D011263:Pregnancy Trimester, Third / Q000276:immunology; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines