title: Enhanced Genetic Characterization of Influenza A(H3N2) Viruses and Vaccine Effectiveness by Genetic Group, 2014-2015.
abstract: During the 2014-2015 US influenza season, expanded genetic characterization of circulating influenza A(H3N2) viruses was used to assess the impact of the genetic variability of influenza A(H3N2) viruses on influenza vaccine effectiveness (VE).
  
  
  
  A novel pyrosequencing assay was used to determine genetic group, based on hemagglutinin (HA) gene sequences, of influenza A(H3N2) viruses from patients enrolled at US Influenza Vaccine Effectiveness Network sites. VE was estimated using a test-negative design comparing vaccination among patients infected with influenza A(H3N2) viruses and uninfected patients.
  
  
  
  Among 9710 enrollees, 1868 (19%) tested positive for influenza A(H3N2) virus; genetic characterization of 1397 viruses showed that 1134 (81%) belonged to 1 HA genetic group (3C.2a) of antigenically drifted influenza A(H3N2) viruses. Effectiveness of 2014-2015 influenza vaccination varied by influenza A(H3N2) virus genetic group from 1% (95% confidence interval [CI], -14% to 14%) against illness caused by antigenically drifted influenza A(H3N2) virus group 3C.2a viruses versus 44% (95% CI, 16%-63%) against illness caused by vaccine-like influenza A(H3N2) virus group 3C.3b viruses.
  
  
  
  Effectiveness of 2014-2015 influenza vaccination varied by genetic group of influenza A(H3N2) virus. Changes in HA genes related to antigenic drift were associated with reduced VE.
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Brendan
authors.initials: B
authors.lastname: Flannery
authors.affiliation: University of Pittsburgh Schools of Health Sciences, Pennsylvania.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Zimmerman
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Larisa V
authors.initials: LV
authors.lastname: Gubareva
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Garten
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention Atlanta Research and Education Foundation, Georgia.
authors.forename: Jessie R
authors.initials: JR
authors.lastname: Chung
authors.affiliation: University of Pittsburgh Schools of Health Sciences, Pennsylvania.
authors.forename: Mary Patricia
authors.initials: MP
authors.lastname: Nowalk
authors.affiliation: Group Health Research Institute, Seattle, Washington.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Jackson
authors.affiliation: Group Health Research Institute, Seattle, Washington.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Jackson
authors.affiliation: Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor.
authors.forename: Arnold S
authors.initials: AS
authors.lastname: Monto
authors.affiliation: Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor.
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Ohmit
authors.affiliation: Marshfield Clinic Research Foundation, Wisconsin.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Belongia
authors.affiliation: Marshfield Clinic Research Foundation, Wisconsin.
authors.forename: Huong Q
authors.initials: HQ
authors.lastname: McLean
authors.affiliation: Baylor Scott & White Health, Texas A&M Health Science Center College of Medicine, Temple.
authors.forename: Manjusha
authors.initials: M
authors.lastname: Gaglani
authors.affiliation: Department of Molecular Virology and Microbiology, and Pediatrics, Baylor College of Medicine, Houston, Texas.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Piedra
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Vasiliy P
authors.initials: VP
authors.lastname: Mishin
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Anton P
authors.initials: AP
authors.lastname: Chesnokov
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention Atlanta Research and Education Foundation, Georgia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Spencer
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Swathi N
authors.initials: SN
authors.lastname: Thaker
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: John R
authors.initials: JR
authors.lastname: Barnes
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Angie
authors.initials: A
authors.lastname: Foust
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Wendy
authors.initials: W
authors.lastname: Sessions
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Xiyan
authors.initials: X
authors.lastname: Xu
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Katz
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention.
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Fry
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002675:Child, Preschool; D005260:Female; D040961:Genetic Drift; D014644:Genetic Variation; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007223:Infant; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014481:United States; D055815:Young Adult
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines
keywords: genetic characterization; influenza; influenza vaccine; pyrosequencing; vaccine effectiveness