title: Real-time surveillance to assess risk of intussusception and other adverse events after pentavalent, bovine-derived rotavirus vaccine.
abstract: BACKGROUND
  A pentavalent, bovine-derived rotavirus vaccine (RotaTeq, Merck) was licensed in 2006 for use in infants. A previously licensed rotavirus vaccine was withdrawn due to elevated risk of intussusception. We prospectively evaluated the risk of intussusception and other pre-specified adverse events among RotaTeq recipients in the Vaccine Safety Datalink.
  
  
  METHODS
  The exposed population included children from age 4 to 48 weeks who received RotaTeq between May 2006 and May 2008. Adverse events over the subsequent 30 days were ascertained from inpatient, outpatient, and emergency department files; cases of intussusception were validated by medical record review. An adaptation of sequential probability ratio testing was employed to compare the cumulative number of observed and expected adverse events on a weekly basis, and a "signal" was generated if the log-likelihood ratio reached a predetermined threshold. This allowed near real-time monitoring to detect selected adverse events. The expected number of cases of intussusception was determined from historical rates in the VSD population.
  
  
  RESULTS
  There were 207,621 doses of RotaTeq administered to the study population; 42% were first doses. Five children had computerized diagnosis codes for intussusception, and 6.75 cases were expected based on historical rates (relative risk = 0.74). No elevation in risk was identified for intussusception or any other adverse event. Two of five children with suspected intussusception based on diagnosis codes met the case criteria after medical record review.
  
  
  CONCLUSIONS
  This study illustrates the feasibility of rapid vaccine safety assessment and provides additional evidence that RotaTeq is not associated with an increased risk of intussusception.
authors.affiliation: Marshfield Clinic Research Foundation, Epidemiology Research Center (ML2), 1000 North Oak Ave, Marshfield, WI 54449, USA. belongia.edward@marshfieldclinic.org
authors.forename: Edward A
authors.initials: EA
authors.lastname: Belongia
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Irving
authors.forename: Irene M
authors.initials: IM
authors.lastname: Shui
authors.forename: Martin
authors.initials: M
authors.lastname: Kulldorff
authors.forename: Edwin
authors.initials: E
authors.lastname: Lewis
authors.forename: Ruihua
authors.initials: R
authors.lastname: Yin
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Lieu
authors.forename: Eric
authors.initials: E
authors.lastname: Weintraub
authors.forename: W Katherine
authors.initials: WK
authors.lastname: Yih
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.forename: James
authors.initials: J
authors.lastname: Baggs
mesh_terms: D005260:Female; D006801:Humans; D007223:Infant; D007443:Intussusception / Q000139:chemically induced* / Q000453:epidemiology*; D008297:Male; D011446:Prospective Studies; D018570:Risk Assessment; D022243:Rotavirus Vaccines / Q000009:adverse effects*; D014613:Vaccines, Attenuated / Q000009:adverse effects
chemical_list: C492535:RotaTeq; D022243:Rotavirus Vaccines; D014613:Vaccines, Attenuated