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Immunizations not up-to-date in many Ontario two-year-olds


A new study from the Institute for Clinical Evaluative Sciences (ICES) shows that many Ontario two-year-olds are not up-to-date with their immunization coverage, despite having a high number of primary care visits.

“Low immunization rates are concerning,” said ICES scientist Dr. Astrid Guttmann. “The up-to-date immunization status of children is an important measure of the effectiveness of the primary healthcare system. In a universal healthcare system such as Canada’s, there are few structural barriers to immunization.“

Despite the importance of tracking this information, there has been little research which reports on immunization rates for children.

To provide further perspective on this issue, investigators tracked over 100,000 urban Ontario babies, born in hospital between July 1, 1997 and June 31, 1998, for two years after their birth. They assessed whether healthcare provider characteristics, as well as health services characteristics, were related to up-to-date immunization status.

Children were considered to have up-to-date immunization coverage if they had at least five immunizations by age two. This represents: the recommended three doses and one booster for Haemophilus influenza, pertussis (whooping cough), diphtheria, polio, and tetanus (known as DPTPHib) to be given at two, four, six, and 18 months; and, one combined dose of measles, mumps and rubella (known as MMR) to be given after the first birthday. Newer vaccines for meningitis, chicken pox and the flu, which were only recently funded by the Ontario government, were not included in the study.

The results showed that only 66% of children had up-to-date immunizations by age two, despite an average of 19 primary care visits in those first two years of life. Children who were up-to-date were more likely to live in a higher income neighbourhood, have more “well baby” and primary care visits in the first two years of life, and have high continuity of care. The up-to-date children were also more likely to have a primary care provider who performed a high volume of primary care for children.

“Although it’s important that parents are aware of which immunizations their child needs from birth to two years, our study reinforces the importance of a regular care provider who sees a lot of children in their practice and has likely developed office-based practices focused on immunizations,” said Dr. Guttmann.

“However, the best method for improving immunization rates is through investments in information technology and electronic health records that can function as recall and reminder systems, as well as data repositories to easily track coverage. These have been shown to be very effective in increasing immunization coverage in other jurisdictions.”

The study, “Volume matters: physician practice characteristics and immunization coverage in young children insured by a universal health plan”, is in the March 2006 issue of the journal Pediatrics.

Author affiliations: ICES (All authors); Population Health Sciences, Research Institute, The Hospital For Sick Children (Drs. Guttmann, Dick, and To); Division of Pediatric Medicine, The Hospital for Sick Children (Drs. Guttmann, Dick and To)

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.


  • Julie Dowdie
  • Media Relations Officer, ICES
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