UMHS LOGOUniversity of Michigan
Department of Pediatrics

Evidence-Based Pediatrics Web Site

Pertussis Vaccine Refusal Increases Risk of Pertussis InfectionEnter Title Here


  • What is the association of vaccine preventable illness with vaccine refusal?

Clinical Bottom Lines

  1. Parents are increasingly concerned about vaccine safety.
  2. Some parents believe vaccine preventable illnesses are not that serious and that their children are at low risk.
  3. Though vaccine refusal still represents a small proportion of parents, there is evidence to suggest that it is increasing over the last decade.

Summary of Key Evidence

  1. Case-control study of a large health maintenance organization in Colorado which identified 156 laboratory confirmed cases or pertussis in children from emergency departments, inpatient wards and outpatient clinics.
  2. Matched to 4 randomly selected controls by gender, length of KPCO enrollment and age at index date (i.e. infection).
  3. Those that refused pertussis vaccination were 22.8 times more likely to be infected (statistically significant).
  4. Eleven percent of all pertussis infections in the population were attributable to vaccine refusal.
  5. Refusers were mostly white, >30 years old and of a higher socioeconomic status.

Additional Comments

  • Vaccine acceptors were shown more likely to the doctor for a URI than vaccine refusers.
  • Vaccines refusers were more likely to be tested for pertussis than vaccine acceptors.


  1. 1. Glanz JM, McClure DL, Magid DJ, Daley MF, France EK, Salmon DA, Hambidge SJ. Parental refusal of pertussis vaccination is associated with an increased risk of pertussis infection in children. Pediatrics. 2009 Jun;123(6):1446-51.

CAT Author: <Stephen Patrick, MD, MPH

CAT Appraisers: <Francis McBee Orzulak, MD

Date appraised: <June 17, 2009

Last updated November 10, 2009
Department of Pediatrics and Communicable Diseases
© 1998-2002 University of Michigan Health System