title: Genetic sequence analysis of influenza viruses and illness severity in ill children previously vaccinated with live attenuated or inactivated influenza vaccine.
abstract: In a large comparative study in 2004-2005, children aged 6-59 months vaccinated with live attenuated influenza vaccine (LAIV) experienced 55% fewer cases of culture-confirmed influenza illness compared with trivalent inactivated influenza vaccine (TIV) recipients. To better understand the characteristics of the breakthrough influenza illnesses, we analyzed the HA1 genetic sequence for all available samples and examined disease severity by strain and treatment group. All 48 A/H1N1 viruses were well-matched to the vaccine, whereas all 276 A/H3N2 viruses and 349 (96%) influenza B viruses were mismatched to the vaccine. The incidence of fever or lower respiratory illness did not differ by strain; however, LAIV recipients had less febrile disease and fewer lower respiratory illnesses than TIV recipients. Viruses of each influenza B lineage caused more illnesses than A/H1N1 viruses; strategies to enhance protection against multiple influenza B lineages should be pursued.
authors.affiliation: MedImmune, Gaithersburg, MD, USA.
authors.forename: Chin-Fen
authors.initials: CF
authors.lastname: Yang
authors.forename: Robert B
authors.initials: RB
authors.lastname: Belshe
authors.forename: George
authors.initials: G
authors.lastname: Kemble
authors.forename: Eyun
authors.initials: E
authors.lastname: Song
authors.forename: Dan
authors.initials: D
authors.lastname: Ye
authors.forename: Brandon
authors.initials: B
authors.lastname: Liang
authors.forename: Tingting
authors.initials: T
authors.lastname: Yi
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ambrose
authors.forename: Kathy
authors.initials: K
authors.lastname: Coelingh
authors.forename: Robert E
authors.initials: RE
authors.lastname: Walker
mesh_terms: D002675:Child, Preschool; D006801:Humans; D015994:Incidence; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics*; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000235:genetics*; D009981:Influenza B virus / Q000145:classification / Q000235:genetics*; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000453:epidemiology*; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D017423:Sequence Analysis, RNA; D014613:Vaccines, Attenuated / Q000008:administration & dosage; D015164:Vaccines, Inactivated / Q000008:administration & dosage
chemical_list: D007252:Influenza Vaccines; D012367:RNA, Viral; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated