Canada’s 2-year measles outbreak officially over: PHAC

An outbreak is a connected cluster of disease cases, not every case that happens afterward. PHAC declared this outbreak over because more than two months had passed since the last reported case linked to it. That means health officials found no continuing chain connected to the outbreak during that period. The decision matters because it marks the end of a two-year national public-health event across many jurisdictions.

The outbreak began in New Brunswick in October 2024. It eventually produced 6,417 linked cases across 10 provinces and territories. PHAC used the absence of a linked case for more than two months as the practical signal that this outbreak’s transmission had stopped. Recent cases are assessed separately when they are not connected to the outbreak.

The declaration does not mean measles has disappeared from Canada. Three confirmed cases were reported between Oct. 4 and Oct. 10, but they were not linked to the two-year outbreak. Officials still expect travel-related cases and are urging people to keep routine vaccinations up to date.

Canada’s outbreak was large and national in reach. PHAC recorded 6,417 cases linked to it across 10 provinces and territories. That total included 1,032 cases reported in 2025. The numbers show why the outbreak became a major public-health concern rather than a small local cluster.

Ontario reported the highest total, with 2,390 cases. Alberta followed with 2,299, while Manitoba reported 1,033. Cases occurred in every province and territory except Yukon, Nunavut, and Newfoundland and Labrador. The outbreak began in New Brunswick in October 2024 and continued for about two years before being declared over.

Most people who became ill had not been vaccinated against measles, according to PHAC. The scale also varied sharply by province, with Ontario and Alberta together accounting for most reported cases. Manitoba separately declared its 20-month outbreak over on Oct. 16, after weeks without a confirmed case.

Global measles-elimination status means a country has stopped ongoing transmission of measles within its borders. Canada lost that status because the outbreak was not a series of brief, unrelated introductions. Instead, the same measles virus strain continued spreading for more than one year. That persistence showed that transmission had become sustained.

In November 2025, PHAC said the Pan American Health Organization had notified it about the loss. A PAHO commission reviewed recent epidemiological and laboratory data. It confirmed sustained transmission of the same measles virus strain in Canada for more than one year. Most people who became ill had not been vaccinated, according to PHAC.

The loss is a formal public-health finding, not a claim that measles exists everywhere in Canada. The outbreak has now ended, but Canada must demonstrate at least 12 months without the strain being sustained before regaining status. It must also strengthen surveillance and show it can quickly stop future outbreaks.

Ending this outbreak means the particular connected event no longer has a reported linked case after more than two months. Elimination is a larger national standard. It means ongoing measles transmission has been stopped within Canada, even though cases may still arrive through travel. A country can end one outbreak without meeting that broader standard.

Canada lost its global elimination status after the same measles strain spread continuously for more than one year. That finding showed sustained transmission inside the country. By contrast, an imported case followed by rapid containment would not necessarily remove elimination status. Eradication is different again: it means measles transmission has been stopped everywhere in the world.

The article states that measles continues to circulate globally, so worldwide eradication has not occurred. Canada’s outbreak is over, but recent confirmed cases still appeared and may be travel-related. Canada can regain elimination status by keeping the strain stamped out for at least 12 months and improving its response systems.

Regaining global elimination status requires more than declaring this outbreak finished. PAHO says Canada must keep the measles strain stamped out for at least 12 months. This period helps demonstrate that ongoing transmission has truly stopped, rather than merely paused after the last known linked case.

Canada must also show stronger surveillance systems and a faster ability to stop outbreaks when measles cases arise. Surveillance helps public-health authorities identify cases, connect them epidemiologically and use laboratory data to track the virus. During the previous review, PAHO confirmed that the same strain had transmitted for more than one year.

Vaccination will remain central to the effort. PHAC said most people who became ill were not vaccinated, and officials urged Canadians to bring routine vaccinations up to date. Even after the outbreak ended, travel-related cases are expected because measles continues to circulate globally. Canada’s progress therefore depends on prevention, detection and rapid control.

Ending an outbreak does not create a permanent barrier against measles. The article notes that measles continues to circulate globally. Someone can therefore bring the virus to Canada through travel after the domestic outbreak has ended. That event would be a new introduction, not automatically a continuation of the old outbreak.

Canada’s Chief Public Health Officer, Dr. Joss Reimer, warned that further travel-related cases can be expected. The federal government reported three confirmed cases between Oct. 4 and Oct. 10, but recent cases were not linked to the two-year outbreak. This example shows how officials distinguish new cases from the completed outbreak.

Vaccination and strong public-health systems can limit what happens next. PHAC said most people who became ill during the outbreak had not been vaccinated. Officials are urging Canadians to keep routine vaccinations up to date, while surveillance helps identify and contain new cases before they create another sustained chain.

Vaccination protects people from becoming ill and reduces the number of people available for measles to spread through. When enough people are protected, population immunity helps interrupt transmission. This is why vaccination rates matter beyond individual protection. PHAC said most people who became ill in the outbreak had not been vaccinated.

Surveillance adds an early-warning system. Health authorities track suspected and confirmed cases, examine epidemiological patterns and use laboratory data to identify whether cases share a virus strain. During Canada’s outbreak, PAHO’s review found sustained transmission of the same strain for more than one year. That evidence led to the loss of elimination status.

These measures work together. Vaccination lowers risk, population immunity limits chains of spread, and surveillance reveals chains that begin despite those protections. Canada now needs higher vaccination rates, stronger surveillance and the ability to stop outbreaks quickly. Those steps support regaining elimination status after at least 12 months without sustained transmission.