Sunday, 8th of February 2015 Print


  1. Nicola P. Klein, MD, PhDa,
  2. Edwin Lewis, MPHa,
  3. Bruce Fireman, MAa,
  4. Simon J. Hambidge, MD, PhDb,
  5. Allison Naleway, PhDc,
  6. Jennifer C. Nelson, PhDd,
  7. Edward A. Belongia, MDe,
  8. W. Katherine Yih, PhD, MPHf,
  9. James D. Nordin, MD, MPHg,
  10. Rulin C. Hechter, MD, PhDh,
  11. Eric Weintraub, MPHi, and
  12. Roger Baxter, MDa

- Author Affiliations

  1. aKaiser Permanente Vaccine Study Center, Oakland, California;
  2. bKaiser Permanente Colorado Institute for Health Research, Denver and Department of Ambulatory Care Services, Denver Health, Denver, Colorado;
  3. cThe Center for Health Research, Kaiser Permanente Northwest, Portland, Oregon;
  4. dGroup Health Cooperative and the University of Washington, Seattle, Washington;
  5. eCenter for Clinical Epidemiology & Population Health, Marshfield Clinic Research Foundation, Marshfield, Wisconsin;
  6. fHarvard Pilgrim Health Care Institute, Boston, Massachusetts;
  7. gHealthPartners Research Foundation, Minneapolis, Minnesota;
  8. hResearch and Evaluation, Kaiser Permanente Southern California, Pasadena, California; and
  9. iImmunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia

Abstract below; full text is at

BACKGROUND AND OBJECTIVES: All measles-containing vaccines are associated with several types of adverse events, including seizure, fever, and immune thrombocytopenia purpura (ITP). Because the measles-mumps-rubella-varicella (MMRV) vaccine compared with the separate measles-mumps-rubella (MMR) and varicella (MMR + V) vaccine increases a toddlers risk for febrile seizures, we investigated whether MMRV is riskier than MMR + V and whether either vaccine elevates the risk for additional safety outcomes.

METHODS: Study children were aged 12 to 23 months in the Vaccine Safety Datalink from 2000 to 2012. Nine study outcomes were investigated: 7 main outcomes (anaphylaxis, ITP, ataxia, arthritis, meningitis/encephalitis, acute disseminated encephalomyelitis, and Kawasaki disease), seizure, and fever. Comparing MMRV with MMR + V, relative risk was estimated by using stratified exact binomial tests. Secondary analyses examined post-MMRV or MMR + V risk versus comparison intervals; risk and comparison intervals were then contrasted for MMRV versus MMR+V.

RESULTS: We evaluated 123 200 MMRV and 584 987 MMR + V doses. Comparing MMRV with MMR + V, risks for the 7 main outcomes were not significantly different. Several outcomes had few or zero postvaccination events. Comparing risk versus comparison intervals, ITP risk was higher after MMRV (odds ratio [OR]: 11.3 [95% confidence interval (CI): 1.9 to 68.2]) and MMR + V (OR: 10 [95% CI: 4.5 to 22.5]) and ataxia risk was lower after both vaccines (MMRV OR: 0.8 [95% CI: 0.5 to 1]; MMR + V OR: 0.8 [95% CI: 0.7 to 0.9]). Compared with MMR + V, MMRV increased risk of seizure and fever 7 to 10 days after vaccination.

CONCLUSIONS: This study did not identify any new safety concerns comparing MMRV with MMR + V or after either the MMRV or the MMR + V vaccine. This study provides reassurance that these outcomes are unlikely after either vaccine. .

  • Copyright © 2015 by the American Academy of Pediatrics

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This Article

  1. Published online January 5, 2015 Pediatrics Vol. 135 No. 2 February 1, 2015
    pp. e321 -e329
    (doi: 10.1542/peds.2014-1822)

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