Table 2. Pan American Health Organization essential criteria for the verification of measles elimination.

Criterion	Indicator	Description
Verify the interruption of endemic measles cases for a period of at least three years from the last known endemic case, in the presence of high-quality surveillance.	Zero cases of endemic transmission.	Criterion met. Canada achieved measles elimination status in 1998. Since then, molecular and epidemiologic data continue to demonstrate that no viral strain has circulated for a period of ≥1 year (3,18,21,22).
Maintain high-quality surveillance, sensitive enough to detect imported and import-related cases.	>2 suspect cases per 100,000 population adequately investigated.	Criterion partially met. CMRSS allows the identification of imported and import-related cases that are confirmed to meet the case definition, but not suspected cases.
Verify the absence of endemic measles virus strains through viral surveillance.	Measles genotype assessed in 80% of outbreaks.	Criterion met. Genotype information was available for 6/6 of outbreaks reported in 2018. Genotype information was also available for 100% of sporadic (non-outbreak related) measles cases.
Verify adequate immunization in the population.	95% of population cohorts aged 1–40 years have received a measles-containing vaccine.	Criterion not met. Canada currently measures (biennially) measles vaccination coverage rates at two and seven years of age, and therefore is unable to assess measles vaccination coverage for all ages 1–40 years. The 2017 childhood National Immunization Coverage Survey estimated first dose measles-containing vaccine coverage in two year olds to be 90% (6).

Abbreviation: CMRSS, Canadian Measles and Rubella Surveillance System