title: Effectiveness of inactivated influenza vaccine in children less than 5 years of age over multiple influenza seasons: a case-control study.
abstract: The effectiveness of influenza vaccine over multiple influenza seasons in children less than 5 years of age has not been well studied. This is especially important to assess because of the recent recommendation for routine influenza vaccination in childhood. We conducted a matched case-control study to assess the vaccine effectiveness of Trivalent Inactivated Influenza Vaccine (TIV) against laboratory-confirmed, medically attended influenza among children 6-59 months of age at the start of each influenza season from 1999-2000 through 2006-2007 in Olmsted County, MN, USA. The children vaccinated against influenza accordingly to the 2007 ACIP guidelines had a lower risk of laboratory-confirmed medically attended influenza illness (Odds Ratio: 0.14, 95% Confidence Interval: 0.03-0.71) than the unvaccinated children. TIV provided strong protection against laboratory-confirmed medically attended influenza in children 6-59 months old in the fully vaccinated group. This trend continued in the partially vaccinated group (Odds Ratio: 0.27, 95% Confidence Interval: 0.07-0.97) but the protection provided maybe suboptimal.
authors.affiliation: Mayo Graduate School of Medicine, Mayo Clinic, Rochester, MN, United States. joshi.avni@mayo.edu
authors.forename: Avni Y
authors.initials: AY
authors.lastname: Joshi
authors.forename: Vivek N
authors.initials: VN
authors.lastname: Iyer
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: St Sauver
authors.forename: Robert M
authors.initials: RM
authors.lastname: Jacobson
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Boyce
mesh_terms: D016022:Case-Control Studies; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008910:Minnesota / Q000453:epidemiology; D012621:Seasons; D016896:Treatment Outcome; D014611:Vaccination; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D007252:Influenza Vaccines; D015164:Vaccines, Inactivated