Vaccine coverage in Canadian children: Highlights from the 2013 childhood National Immunization Coverage Survey (cNICS)
The Public Health Agency of Canada (PHAC) routinely monitors immunization coverage in Canada through the childhood National Immunization Coverage Survey (cNICS). Since 1994, the cNICS has been conducted every two years to estimate national uptake for all routine childhood immunizations recommended by the National Advisory Committee on Immunization (NACI). The survey also includes questions on parental knowledge, attitudes and beliefs which influence decisions on immunization for their children. National level immunization coverage estimates provide helpful information on the level of protection against disease and can identify general trends over time in uptake and attitudes toward vaccinations.
Starting in 2011, PHAC asked Statistics Canada, a recognized expert in population statistics and survey methodology, to conduct the cNICS on its behalf. In 2013, PHAC invested in a larger sample size and consulted with provinces and territories on the methodology in order to get better estimates of immunization coverage in Canada. The 2013 cycle of cNICS was conducted by Statistics Canada between September 2013 and March 2014. Included in the survey were approximately 24,000 Canadian children whose parents had an immunization record and who were 2, 7 or 17 years of age at the time of the survey. Girls between the ages of 12 and 14 years were also surveyed to determine coverage of Human Papillomavirus (HPV) immunization.
The childhood vaccines included in the cNICS questionnaire were those that are routine and publicly-funded under provincial/territorial programs:
- DPT: diphtheria, pertussis, and tetanus;
- MMR: measles, mumps, rubella;
- Human Papillomavirus (HPV);
- Hepatitis B;
- Haemophilus influenzae type B (Hib);
- Meningococcal-C conjugate;
- Pneumococcal conjugate; and,
Results from the cNICS 2013 show that the proportion of children whose parents/guardians reported they had never received any immunization was 1.5% across all age groups, and that the majority of Canadian children are immunized against vaccine preventable diseases.
When looking at specific vaccines at age two, the survey showed the following coverage rates:
- Polio (three doses): 91%
- DPT (four doses): 77%
- Hib (four doses): 72%
- MMR: 89%
- Varicella: 73%
- Meningococcal C: 89%
- Pneumococcal: 79%
Approximately 90% of children were immunized against polio at ages 2 (and 7 and 17). This finding is important in helping to interpret the observed coverage rate for DPT (77%) and Hib (72%) for two year olds. The polio vaccination is given concurrently with DPT and Hib and children are considered to be up to date on their immunizations for polio after three doses. For DPT and Hib, an additional booster is required at 18 months (making for four doses). The observed coverage rate for DPT and Hib may reflect the fact that children were likely behind on their immunizations at the time of the survey, and had not yet received their 18 month booster.
Similar to polio, almost 90% of children were immunized for measles, mumps and rubella (MMR) at age 2. Although just less than three quarters of children were immunized against varicella, it is important to consider that relative to DPT, polio and MMR, varicella is still a new vaccine for which universal immunization programs continue to work at increasing their uptake. It is not uncommon for newer vaccines to show lower coverage rates when compared to more-established vaccines.
As with varicella, meningococcal C conjugate and pneumococcal conjugate are relatively new immunizations compared to DPT and MMR. Universal immunization programs were established in the early 2000's for these two vaccines, and uptake is still increasing across provinces and territories. The observed coverage rates for these immunizations for two year olds were 89% and 79% respectively.
For other age groups, results show that almost three quarters of girls between the ages of 12 and 14 were immunized against HPV, and by age 17, almost 90% of children were immunized against Hepatitis B.
The cNICS 2013 also asked about knowledge, attitudes and beliefs related to vaccines and vaccination, and it revealed that 95% of parents thought that childhood vaccines are safe. Similarly, 97% thought that vaccines are effective and important for children's health.
On the other hand, there was some concern expressed about possible side effects of vaccines. Almost 70% of parents expressed concern around the side effects of vaccines, and over a third wrongly believed that a vaccine can cause the same disease it was meant to prevent. Almost five per cent of parents strongly agreed that alternative practices, such as homeopathy or chiropractic, can eliminate the need for vaccines. Homeopathic alternatives, such as nosodes, are not a substitute for vaccines. There are no substitutes for vaccines. These results show there is still room for improvement in increasing knowledge about immunization.
As with any large scale survey, the cNICS has some limitations that must be considered when interpreting the results. It is possible that those who participated in the survey do not adequately represent the full Canadian population. As well, it is possible that some immunizations that occurred were not captured by the survey because parents forgot or were relying on immunization records that were not up to date.
The 2013 cNICS is the largest national-level immunization coverage survey ever carried out in Canada. Results from the survey showed that the majority of Canadian children are immunized against vaccine-preventable diseases, but there is room to improve in keeping vaccinations up to date.
The results and methodology of this survey are being shared with the World Health Organization in an effort to contribute to the improvement of the accuracy and validity of immunization coverage estimates in all countries. Currently, member countries use differing methodologies to estimate coverage, which makes it difficult to compare coverage rates internationally.
NOTE: This document was initially issued on July 20, 2015. The numbers presented in it have been revised on December 13th, 2016 based on the updated immunization coverage estimates published by Statistics Canada in the Daily.
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