title: Immunogenicity and reactogenicity to Haemophilus influenzae type B (Hib) conjugate vaccine among rural Alaska adults.
abstract: BACKGROUND
  Despite routine vaccination and declining disease rates, Haemophilus influenzae type b (Hib) invasive disease still occurs in rural Alaska. Colonization studies indicate persistent transmission of Hib among village residents, including adults. As part of a project to eliminate Hib carriage in three rural villages, we evaluated a cohort of Alaska adults for antibody response and reactogenicity to a single dose of Hib conjugate vaccine (HbOC).
  
  
  METHODS
  75 previously unvaccinated, randomly-selected adults in one village received a single dose of HbOC vaccine and completed a side-effects diary. Sera and oropharyngeal specimens were collected at baseline, two months and one year.
  
  
  RESULTS
  No participants were colonized with Hib or reported serious side-effects. At baseline, 97% of adults had IgG anti-PRP concentrations > or = 0.15 microg/mL, 69% > or = 1 microg/mL, and 28% > or = 5 microg/mL. Two months post-vaccination, 100% of participants had concentrations > or = 0.15 microg/mL, 93% > or = 1 microg/mL, and 86% > or = 5 microg/mL. After 1 year, 98% had IgG anti-PRP concentrations > or = 0.15 microg/mL, 86% > or = 1 microg/mL, and 67% > or = 5 microg/mL. GMCs were 1.9, 33.3 and 8.4 microg/mL at baseline, 2 months and 1 year post-vaccine, respectively (p < 0.01). Serum bactericidal activity increased from a baseline geometric mean titer of 2,205 to 8,349 two months post vaccination and declined to 1102 after one year.
  
  
  CONCLUSIONS
  HbOC vaccine was immunogenic and well-tolerated among Alaskan adults. Nearly 90% of the adults developed an antibody level associated with protection against Hib colonization which persisted for 1 year in 67% of participants.
authors.affiliation: Arctic Investigations Program, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, Alaska, USA. CDentinger@cdc.gov
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Dentinger
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Hennessy
authors.forename: Lisa R
authors.initials: LR
authors.lastname: Bulkow
authors.forename: Alisa L
authors.initials: AL
authors.lastname: Reasonover
authors.forename: Sandra
authors.initials: S
authors.lastname: Romero-Steiner
authors.forename: Patricia F
authors.initials: PF
authors.lastname: Holder
authors.forename: Patricia Gomez
authors.initials: PG
authors.lastname: de Leon
authors.forename: George M
authors.initials: GM
authors.lastname: Carlone
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Parks
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Parkinson
authors.forename: Rosalyn J
authors.initials: RJ
authors.lastname: Singleton
authors.forename: Orin S
authors.initials: OS
authors.lastname: Levine
authors.forename: Jay C
authors.initials: JC
authors.lastname: Butler
mesh_terms: D000328:Adult; D000413:Alaska; D000907:Antibodies, Bacterial / Q000097:blood; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D012424:Rural Population; D018074:Vaccines, Conjugate / Q000009:adverse effects* / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D018073:Haemophilus Vaccines; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D018074:Vaccines, Conjugate