title: Intussusception after rotavirus vaccines reported to US VAERS, 2006-2012.
abstract: BACKGROUND
  In 2006 and 2008, 2 new rotavirus vaccines (RotaTeq [RV5] and Rotarix [RV1]) were introduced in the United States.
  
  
  METHODS
  We assessed intussusception events reported to the Vaccine Adverse Event Reporting System from February 2006 through April 2012 for RV5 and from April 2008 through April 2012 for RV1. For RV5, we conducted a self-controlled risk interval analysis using Poisson regression to estimate the daily reporting ratio (DRR) of intussusception comparing average daily reports 3 to 6 versus 0 to 2 days after vaccination. We calculated reporting rate differences based on DRRs and background rates of intussusception. Sensitivity analyses were conducted to assess effects of differential reporting completeness and inaccuracy of baseline rates. Few reports were submitted after RV1, allowing only a descriptive analysis.
  
  
  RESULTS
  The Vaccine Adverse Event Reporting System received 584 confirmed intussusception reports after RV5 and 52 after RV1, with clustering 3 to 6 days after both vaccines. The DRR comparing the 3- to 6-day and the 0- to 2-day periods after RV5 dose 1 was 3.75 (95% confidence interval = 1.90 to 7.39). There was no significant increase in reporting after dose 2 or dose 3. Over all 3 doses, the excess risk of intussusception was 0.79 events (95% confidence interval = -0.04 to 1.62) per 100 000 vaccinations. From the sensitivity analyses, we conclude that under a worst-case scenario, the DRR could be 5.00 and excess risk per 100 000 doses could be 1.36.
  
  
  CONCLUSIONS
  We observed a persistent clustering of reported intussusception events 3 to 6 days after the first dose of RV5 vaccination. This clustering could translate to a small increased risk of intussusception, which is outweighed by the benefits of rotavirus vaccination.
authors.affiliation: National Center for Emerging and Zoonotic Infectious Diseases, Atlanta, GA, USA. pyh0@cdc.gov
authors.forename: Penina
authors.initials: P
authors.lastname: Haber
authors.forename: Manish
authors.initials: M
authors.lastname: Patel
authors.forename: Yi
authors.initials: Y
authors.lastname: Pan
authors.forename: James
authors.initials: J
authors.lastname: Baggs
authors.forename: Michael
authors.initials: M
authors.lastname: Haber
authors.forename: Oidda
authors.initials: O
authors.lastname: Museru
authors.forename: Xin
authors.initials: X
authors.lastname: Yue
authors.forename: Paige
authors.initials: P
authors.lastname: Lewis
authors.forename: Frank
authors.initials: F
authors.lastname: Destefano
authors.forename: Umesh D
authors.initials: UD
authors.lastname: Parashar
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems; D006801:Humans; D007223:Infant; D007443:Intussusception / Q000453:epidemiology* / Q000209:etiology*; D012306:Risk; D018570:Risk Assessment; D012400:Rotavirus Infections / Q000517:prevention & control*; D022243:Rotavirus Vaccines / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology
chemical_list: D022243:Rotavirus Vaccines
keywords: VAERS; adverse event; intussusception; rotavirus vaccines; safety monitoring