Immunization Monitoring Program, Active: a model of active surveillance of vaccine safety

Semin Pediatr Infect Dis. 2003 Jul;14(3):213-9. doi: 10.1016/s1045-1870(03)00036-0.


In Canada since 1993 the nation's passive system for reporting postimmunization adverse events has been supplemented by the active surveillance of inpatients at 10 to 12 pediatric referral centers, a system referred to as the Immunization Monitoring Program, Active. Participating centers are located from coast-to-coast and receive referrals from every province and territory. Approximately 20 percent of the population aged 0 to 12 years lives in the immediate vicinity of these centers. Nurse monitors at each center search for numerous target conditions, including postimmunization adverse events and vaccine-preventable infections. Vaccine safety observations have included (1) a substantial decrease in the risk of the development of febrile seizures and hypotonic-hyporesponsive episodes since the country switched from whole-cell to acellular pertussis-containing vaccines, (2) no evidence for encephalopathy resulting from the latter vaccines, (3) a generally benign outcome with postimmunization thrombocytopenia cases, and (4) an unexpectedly high rate of disseminated bacille Calmette-Guérin infections among aboriginal infants. Concomitant disease surveillance has been important for sustaining the surveillance system because few postimmunization adverse events require hospital admission.

MeSH terms

  • Adverse Drug Reaction Reporting Systems*
  • Canada / epidemiology
  • Child
  • Child, Preschool
  • Communicable Disease Control*
  • Communicable Diseases / epidemiology
  • Encephalomyelitis, Acute Disseminated / epidemiology
  • Encephalomyelitis, Acute Disseminated / etiology
  • Humans
  • Immunization / adverse effects*
  • Immunization Programs
  • Infant
  • Muscle Hypotonia / epidemiology
  • Muscle Hypotonia / etiology
  • Paralysis / epidemiology
  • Paralysis / etiology
  • Population Surveillance*
  • Seizures, Febrile / epidemiology
  • Seizures, Febrile / etiology
  • Thrombocytopenia / epidemiology
  • Thrombocytopenia / etiology
  • Tuberculosis / epidemiology
  • Tuberculosis / etiology
  • Vaccines / adverse effects*


  • Vaccines