title: Revaccination with a 23-valent pneumococcal polysaccharide vaccine induces elevated and persistent functional antibody responses in adults aged 65 > or = years.
abstract: BACKGROUND
  Older adults are at high risk of developing invasive pneumococcal disease, but the optimal timing and number of vaccine doses needed to prevent disease among this group are unknown. We compared revaccination with 23-valent pneumococcal polysaccharide vaccine (PN23) with primary vaccination for eliciting initial and persistent functional antibody responses.
  
  
  METHODS
  Subjects aged > or = 65 years were enrolled. Functional (opsonic) and total immunoglobulin (Ig) G antibody levels were measured following either PN23 primary vaccination (n = 60) or revaccination 3-5 years after receiving a first PN23 vaccination (n = 60). Antibody against vaccine serotypes 4, 14, and 23F was measured at prevaccination (day 0), 30 days after vaccination, and 5 years after vaccination.
  
  
  RESULTS
  By day 30, both primary vaccination and revaccination induced significant increases in opsonic and IgG antibody levels. Day 30 levels following revaccination were slightly lower but not significantly different than those after primary vaccination. Year 5 levels were similar in both groups and remained significantly higher than prevaccination levels for primary vaccination subjects. There was good agreement between postvaccination opsonic and IgG antibody levels.
  
  
  CONCLUSIONS
  Revaccination of older adults with PN23 was comparable to primary vaccination for inducing elevated and persistent functional and IgG antibody responses.
authors.affiliation: Merck Research Laboratories, North Wales, Pennsylvania 19454, USA. susan_manoff@merck.com
authors.forename: Susan B
authors.initials: SB
authors.lastname: Manoff
authors.forename: Charles
authors.initials: C
authors.lastname: Liss
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Caulfield
authors.forename: Rocio D
authors.initials: RD
authors.lastname: Marchese
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Silber
authors.forename: John
authors.initials: J
authors.lastname: Boslego
authors.forename: Sandra
authors.initials: S
authors.lastname: Romero-Steiner
authors.forename: Gowrisankar
authors.initials: G
authors.lastname: Rajam
authors.forename: Nina E
authors.initials: NE
authors.lastname: Glass
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Whitney
authors.forename: George M
authors.initials: GM
authors.lastname: Carlone
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology* / Q000378:metabolism; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines