title: Hospitalizations within 14days of vaccination among pediatric recipients of the live attenuated influenza vaccine, United States 2010-2012.
abstract: Live attenuated influenza vaccine (LAIV) is safe in healthy children ⩾2years. The original clinical trials excluded individuals with underlying conditions; however, post-marketing data suggest LAIV may be safe for these populations.
  
  
  
  We analyzed MarketScan Commercial Claims Databases from 2010 to 2012 to describe hospitalizations within 14days of vaccination among LAIV recipients. We evaluated LAIV recipients aged 2-18years and defined underlying conditions by presence of inpatient or outpatient ICD-9 code during the previous calendar year. We excluded asthma and immunocompromising conditions. We defined risk windows as 1-7days and 8-14days after vaccination; the control period was 12-4days prior to and 15-23days after vaccination. We conducted a self-controlled case series analysis using a conditional Poisson regression model to estimate incidence-rate ratios (IRR).
  
  
  
  1,216,123 children aged 2-18years received LAIV from 2010 to 2012. 634 children met our inclusion criteria and were hospitalized during the observation period (12days prior to vaccination to 23days after vaccination). Of those hospitalized, 72 (11.4%) had non-asthma, non-immunocompromising underlying conditions. Children with non-asthma, non-immunocompromising underlying conditions had an all-cause hospitalization IRR of 1.1 (95% CI 0.6-2.0, p=0.83) in the 1-7day risk period and 0.9 (95% CI 0.4-1.7, p=0.67) in the 8-14day risk period. Children with no underlying conditions had an all-cause hospitalization IRR of 0.9 (0.8-1.2, p=0.60) in the 1-7day risk period and 1.1 (95% CI 0.9-1.3, p=0.53) in the 8-14day risk period. There were no differences in all-cause hospitalization risk in individuals with non-asthma, non-immunocompromising underlying conditions compared to those without underlying conditions in the 1-7day (p=0.88) or 8-14day (p=0.24) risk period.
  
  
  
  We found no evidence of differences in post-LAIV hospitalization risk among children with non-asthma, non-immunocompromising underlying conditions compared to healthy children.
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Road MS A-32, Atlanta, GA 30329, USA; Epidemic Intelligence Service assigned to Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Road MS A-32, Atlanta, GA 30329, USA. Electronic address: amillman@cdc.gov.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Millman
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Road MS A-32, Atlanta, GA 30329, USA. Electronic address: SNB9@cdc.gov.
authors.forename: Sue
authors.initials: S
authors.lastname: Reynolds
authors.affiliation: Immunization Safety Office, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, 1600 Clifton Road MS D-26, Atlanta, GA 30329, USA. Electronic address: LZD5@cdc.gov.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Duffy
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Road MS A-32, Atlanta, GA 30329, USA. Electronic address: NCZ5@cdc.gov.
authors.forename: Jufu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Road MS A-32, Atlanta, GA 30329, USA. Electronic address: bpot6v6g@att.net.
authors.forename: Paul
authors.initials: P
authors.lastname: Gargiullo
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Road MS A-32, Atlanta, GA 30329, USA. Electronic address: AGF1@cdc.gov.
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Fry
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D011358:Product Surveillance, Postmarketing; D014481:United States; D014611:Vaccination / Q000009:adverse effects*; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated
keywords: Influenza; Live attenuated influenza vaccine; Pediatrics; Vaccination