Monday marks a full year of continuous measles transmission in Canada, a milestone that’s poised to set the country back decades on a global health commitment. Ongoing transmission in the United States puts it among a group of countries that also face scrutiny from international leaders and are at risk of a similar fate.

All of the World Health Organization’s regions have committed to eliminate measles by 2030, defined by the absence of local virus transmission for any period longer than 12 months. Canada achieved this goal in 1998, but falling vaccination rates set the stage for cases to grow into a massive — and ongoing — outbreak, putting the country and region at risk of losing elimination status.

In early November, the Pan American Health Organization, a regional WHO office, will convene an annual meeting of its Measles and Rubella Elimination Regional Monitoring and Re-Verification Commission to formally determine the status of measles elimination across the region.

“A country is no longer considered to be measles free if the virus returns and transmission is sustained continuously for more than a year,” WHO said in a statement. “There are no formal consequences of losing measles elimination status, however having measles again as an endemic disease will have a profound negative impact on communities, including