title: Immunogenicity of trivalent inactivated influenza vaccination received during pregnancy or postpartum.
abstract: OBJECTIVE
  To estimate the effects of gestational age and other maternal factors on immunologic responses to influenza vaccination.
  
  
  METHODS
  Antepartum and postpartum women receiving influenza vaccination as part of routine clinical care were enrolled through four consecutive vaccination seasons (starting October 2006 through January 2010). Immunologic responses to trivalent inactivated influenza vaccine and monovalent H1N1 were assessed as well as factors influencing vaccine responsiveness. Serum samples were obtained at baseline and 4-8 weeks postvaccination.
  
  
  RESULTS
  Two hundred thirty-nine participants were included in the current analysis. Seroconversion rates to trivalent inactivated influenza vaccine strains were lowest in the first trimester (54.8%) and immediately postpartum (54.8%) and were highest in the late third trimester (69.6%) and late postpartum (69.4%); these differences were not statistically significant (P=.23). In a multivariable model, higher baseline antibody levels (P<.001) and prior year flu vaccination (P=.03) were both significantly associated with reduced odds of seroconversion. Overall, results were consistent when comparing trivalent inactivated influenza vaccine and monovalent pandemic H1N1 responses. Although there was overall no significant association between gestational age at vaccination (P=.23) or prepregnancy body mass index (P=.16), we observed somewhat lower rates of seroconversion for women vaccinated in the first trimester and for obese women.
  
  
  CONCLUSIONS
  Adequate immunologic responses to inactivated influenza vaccines were demonstrated during pregnancy and the postpartum period. No diminution of immunogenicity was observed in the third trimester, a time of increased clinical vulnerability to influenza.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Science, Mount Sinai School of Medicine, New York, New York 10029, USA. rhoda.sperling@mssm.edu
authors.forename: Rhoda S
authors.initials: RS
authors.lastname: Sperling
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Engel
authors.forename: Sylvan
authors.initials: S
authors.lastname: Wallenstein
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kraus
authors.forename: Jose
authors.initials: J
authors.lastname: Garrido
authors.forename: Tricia
authors.initials: T
authors.lastname: Singh
authors.forename: Lisa
authors.initials: L
authors.lastname: Kellerman
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Moran
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D005260:Female; D005865:Gestational Age; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000097:blood / Q000517:prevention & control*; D009765:Obesity / Q000097:blood / Q000276:immunology; D049590:Postpartum Period / Q000276:immunology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control*; D015164:Vaccines, Inactivated / Q000097:blood / Q000276:immunology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated