[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address Please contact the publisher to request reinstatement.
[Skip to Content Landing]
Original Investigation
November 2013

Association Between Undervaccination With Diphtheria, Tetanus Toxoids, and Acellular Pertussis (DTaP) Vaccine and Risk of Pertussis Infection in Children 3 to 36 Months of Age

Author Affiliations
  • 1Institute for Health Research, Kaiser Permanente Colorado, Denver
  • 2Department of Epidemiology, Colorado School of Public Health, Aurora
  • 3Department of Pediatrics, University of Colorado, Aurora
  • 4Community Health Services, Denver Health, Colorado
  • 5Kaiser Permanente Vaccine Study Center, Oakland, California
  • 6Center for Child Health Care Studies, Department of Population Medicine, Harvard Pilgrim Health Care Institute and Harvard Medical School, Boston, Massachusetts
  • 7Group Health Cooperative, Seattle, Washington
  • 8Kaiser Permanente Northwest, Portland, Oregon
  • 9HealthPartners Research Foundation, Minneapolis, Minnesota
  • 10Department of Research and Evaluation, Southern California Kaiser Permanente, Pasadena
  • 11Immunization Safety Office, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
JAMA Pediatr. 2013;167(11):1060-1064. doi:10.1001/jamapediatrics.2013.2353

Importance  Undervaccination is an increasing trend that potentially places children and their communities at an increased risk for serious infectious diseases.

Objective  To examine the association between undervaccination and pertussis in children 3 to 36 months of age.

Design  Matched case-control study with conditional logistic regression analysis.

Setting  Eight managed care organizations of the Vaccine Safety Datalink between 2004 and 2010.

Participants  Each laboratory-confirmed case of pertussis (72 patients) was matched to 4 randomly selected controls (for a total of 288 controls). The case patients were matched to controls by managed care organization site, sex, and age at the index date. The index date was defined as the date of pertussis diagnosis for the case patients.

Exposure  Undervaccination for the diphtheria, tetanus toxoids, and acellular pertussis (DTaP) vaccine. Undervaccination was defined as the number of doses of DTaP vaccine that was either missing or delayed by the index date. Case patients and controls could be undervaccinated by 0, 1, 2, 3, or 4 doses of DTaP vaccine. Children undervaccinated by 0 doses were considered age-appropriately vaccinated by the index date.

Main Outcome and Measure  Pertussis.

Results  Of the 72 case patients with pertussis, 12 (16.67%) were hospitalized, and 34 (47.22%) were undervaccinated for DTaP vaccine by the date of pertussis diagnosis. Of the 288 matched controls, 64 (22.22%) were undervaccinated for DTaP vaccine. Undervaccination was strongly associated with pertussis. Children undervaccinated for 3 or 4 doses of DTaP vaccine were 18.56 (95% CI, 4.92-69.95) and 28.38 (95% CI, 3.19-252.63) times more likely, respectively, to have received a diagnosis of pertussis than children who were age-appropriately vaccinated.

Conclusions and Relevance  Undervaccination with DTaP vaccine increases the risk of pertussis among children 3 to 36 months of age.