Table 1.
Methods used for immunization coverage assessment, by P/T.
| NWT | BC | AB | SK | MB | ON | QC | NS | NL | PEI | NB | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Measures up-to-date coverage | ✓ | ✓,1 | ✓ | ✓ | ✓ | x | ✓ | ✓ | ✓ | ✓ | ✓ | |
| Measures on-time coverage | ✓ | ✓ | x | ✓ | ✓ | x | ✓,2 | x | x | x | x | |
| Measures coverage using other method(s) | x | ✓,3 | ✓ | x | x | ✓,4 | x | x | x | x | x | |
| Coverage definition includes valid doses only |
valid | valid | valid | valid | valid | valid | valid and all5 | valid | valid | all | valid | |
| Grace period6 considered for valid dose assessment | n/a | x | ✓ | ✓ | ✓ | x | x | x | x | n/a | ✓ | |
| Denominator data source for coverage assessment | HI and statistics bureau | Mixed7 | HI | Mixed8 | HI | SL | Mixed 9 | SL | SL | Mixed10 | SL | |
| Age milestones for assessing coverage | 2 yr. | 2 , 7 yr. | 2 yr. | 2, 7 and 17 yr. | 1, 2,7, 11 and 17 yr. | 7, 12,13 and 17 yr. | 15 and 24 mo. | x | 2 yr. | 2 yr. | School entry (4-5 yrs) | |
| Grade milestones for assessing coverage | x | Grade 6 and 9 | Grade 1 and 5 | x | x | x | Grade 4 and 9 | Grade 7 | Grade 4, 6 and 9 | Grade 1, Grade 6 and 9 | Grade 7 and 9 | |
| Exceptions to coverage measurement | x | Influenza, Hepatitis A | x | x | x | Influenza Rotavirus11 |
x | childhood vaccines | Influenza, | Influenza | Influenza, childhood vaccines | |
| Frequency of coverage measurement | bi-annually | annually for all age groups | annually | quarterly (age 2 and 7), annually for other ages | annually | annually | bi-annually, annually12 | annually | annually | annually | annually | |
denotes yes; x denotes no; n/a denotes not applicable; HI denotes health insurance; SL denotes school registration lists
British Columbia assesses up-to-date coverage for all recommended vaccines for the 2 and 7 year old milestones, and assessment of vaccines scheduled for administration in Grade 6 and 9.
Quebec assesses on-time coverage using a coverage survey for 15 and 24 month olds.
British Columbia has used IDEA score periodically to examine timeliness of immunization among 2 year olds.11
Ontario has historically used a “complete-for-age’ definition. The exception is the method used for measles-mumps-rubella vaccine, which identifies the proportion of students who have received one or two doses of MMR vaccine by antigen.
Quebec assesses coverage for 15 and 24 months olds using a coverage survey, reporting two different estimates: one based on valid doses only and the other based on all doses. Coverage calculated from the provincial registry (i.e., measles) considers only valid doses.
Saskatchewan and New Brunswick apply a four day grace period to valid dose assessment. In Manitoba, a seven day grace period may be applied in certain scenarios. In Alberta, inactivated vaccines given 4 days before the minimum age or 4 days before the minimum interval has elapsed require consultation with the local Medical Officer of Health to determine if the dose is accepted and/or for further scheduling advice.
Denominator source in British Columbia varies across the health authorities where some regions rely on registry data (as derived from public health records when a person is born in the province or presents themselves to public health after moving from another province) or Ministry of Education enrollment estimates, school class lists or combination of both data sources including information collected on consent forms.
The denominator source in Saskatchewan is based on the numbers derived from public health records when a person is born in the province or presents themselves to public health after moving from another province).
Quebec does not have a population-based immunization registry because only those who received at least one dose of vaccine are included in the provincial data. The denominator data source for coverage assessed among Grade 4 and 9 students is the number of students attending school each year. The exception is a measles vaccine registry which includes the Quebec population born on and after 1970, based on the following information sources: health insurance database, Ministry of Education student database. In addition, a coverage survey is used to assess toddler immunization coverage (15 and 24 months old). The sampling frame for the coverage survey is the provincial health insurance database.
PEI uses the discharge abstract data or perinatal database to identify infants born in PEI (all babies are born in the hospital with very few exceptions) and uses data from the Department of Education for school age indicators.
The first birth cohort eligible for publicly-funded rotavirus vaccine has not yet reached the aged of routine coverage assessment in Ontario (age 7 years). When this occurs in the 2019-20 school year, rotavirus coverage will be assessed through routine processes. Other processes (i.e. doses distributed) are being used in the interim.
Quebec assesses coverage on a bi-annual basis for the 15 and 24 month olds. Coverage is assessed in grade 4 and 9 for Hepatitis B and HPV on an annual basis.