title: Reactogenicity and immunogenicity of an inactivated influenza vaccine administered by intramuscular or subcutaneous injection in elderly adults.
abstract: In many countries there is no clear recommendation regarding the preferred route of administration of inactivated influenza vaccines. In a randomised, observer blind study of 720 elderly subjects, a split, trivalent influenza vaccine was significantly more immunogenic for both A strains (H3N2 and H1N1, p = 0.0016 and 0.003, respectively) when given intramuscularly compared to subcutaneously. This difference was due entirely to a gender effect, with females in the intramuscular (IM) group having a significantly greater serological response than females in the subcutaneous (SC) group for both of these strains. Similar results were seen with local adverse effects. These data suggest that vaccination practices that ensure intramuscular injection are required for optimal administration of influenza vaccines in the elderly.
authors.affiliation: Discipline of General Practice, School of Medical Practice & Population Health, University of Newcastle, Callaghan, NSW 2308, Australia. drifcook@bigpond.com
authors.forename: Ian F
authors.initials: IF
authors.lastname: Cook
authors.forename: Ian
authors.initials: I
authors.lastname: Barr
authors.forename: Gunter
authors.initials: G
authors.lastname: Hartel
authors.forename: Dimity
authors.initials: D
authors.lastname: Pond
authors.forename: Alan W
authors.initials: AW
authors.lastname: Hampson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D007273:Injections, Intramuscular; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
chemical_list: D007252:Influenza Vaccines; D015164:Vaccines, Inactivated