title: Influenza Vaccine is Protective Against Laboratory-confirmed Influenza in Obese Children.
abstract: BACKGROUND
  Obesity emerged as a novel risk factor for severe disease during the 2009 H1N1 influenza pandemic. Murine studies indicate that obesity is associated with ineffective response to influenza vaccine, but few human studies exist. We aimed to determine if influenza vaccine is protective against laboratory-confirmed influenza in obese children.
  
  
  METHODS
  Body mass index, vaccination status, and laboratory-confirmed influenza data were analyzed from a previously conducted prospective study in which active surveillance for influenza-like illness was conducted in 8 elementary schools in Los Angeles County during the 2010-2011 influenza season. Polymerase-chain reaction (PCR) was performed on combined nose/throat swabs collected from children with influenza-like illness at presentation to the school nurse or during absenteeism.
  
  
  RESULTS
  Of 4260 children with height/weight data, 1191 (28.0%) were obese (body mass index ≥95th percentile). Respiratory specimens were obtained from 858 (20.1%) children. Unvaccinated obese compared with vaccinated obese children acquired 3 times more PCR-confirmed influenza (62 vs. 17 per 1000 children, P = 0.003) and missed more school days (4.6 vs. 3.2 per 100 school days, P < 0.001) during influenza season. Obese children with PCR-confirmed influenza were more likely to present with cough (86.2 vs. 72.4%, P = 0.030) and missed more school per episode (2.4 vs.1.9 days, P = 0.023) compared with nonobese children. Among vaccinated children, rates of PCR-confirmed influenza were similar in obese and nonobese children (17 vs. 20 per 1000 children, P = 0.77).
  
  
  CONCLUSIONS
  Obese children with PCR-confirmed influenza suffered from more cough and missed more school days than their nonobese peers. Influenza vaccination protected obese children against PCR-proven influenza illness.
authors.affiliation: From the *Division of Infectious Diseases, Hasbro Children's Hospital, Providence, Rhode Island; †Alpert Medical School of Brown University, Providence, Rhode Island; ‡Division of Infectious Diseases, Children's Hospital Los Angeles, Los Angeles, CA; §Los Angeles County Department of Public Health, and ¶Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Smit
authors.forename: Hai-Lin
authors.initials: HL
authors.lastname: Wang
authors.forename: Edward
authors.initials: E
authors.lastname: Kim
authors.forename: Noel
authors.initials: N
authors.lastname: Barragan
authors.forename: Grace M
authors.initials: GM
authors.lastname: Aldrovandi
authors.forename: Alvin Nelson
authors.initials: AN
authors.lastname: El Amin
authors.forename: Laurene
authors.initials: L
authors.lastname: Mascola
authors.forename: Pia S
authors.initials: PS
authors.lastname: Pannaraj
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000235:genetics; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control* / Q000821:virology; D008297:Male; D009765:Obesity / Q000453:epidemiology*; D062486:Public Health Surveillance; D012307:Risk Factors; D013334:Students; D014611:Vaccination
chemical_list: D007252:Influenza Vaccines