Canada has lost its measles elimination status after nearly three decades, a public health setback that was widely expected amid an ongoing outbreak that has grown to more than 5,000 cases across the country.
Still, confirmation from the Pan American Health Organization (PAHO) on Monday that Canada is no longer considered free of endemic measles for the first time since 1998 has come as a blow to many, especially those who work in health care and public health.
"To lose this elimination status is devastating in many ways because it is so preventable. It is embarrassing and sad," said Dr. Anne Pham-Huy, chair of Immunize Canada and a pediatric infectious disease specialist and clinical immunologist at CHEO. She works with children who are unable to get vaccinated and rely on herd immunity to remain protected.
"In medicine, we hope to advance and improve over time. It is heartbreaking to go backwards and this is what we are doing. I am sad about this. We shouldn't be here, but we are."
University of Ottawa epidemiologist Raywat Deonandan called Canada's loss of measles elimination status a wake-up call.
"It is not a crisis in the sense an epidemic is at our doorstep but strongly indicative of fragility in our public health system." He said Canadians have to "step up the defence of the rational and that is something that all corners of society must engage in."
Deonandan and others called on members of the public to get vaccinated and talk about the importance of vaccines as part of a broader effort to combat vaccine hesitancy and reduce Canada's risk of spread of measles and other diseases.
He said the loss of elimination statust signals that the disease is not under control which can both erode public confidence and change the way people around the world view Canada.
"It is frustrating."
Monday's declaration has also increased calls for a national vaccine registry, something PAHO recommended as part of strengthening surveillance. Canada is the only G7 country without a national vaccination registry, something that acts as a barrier to people keeping up to date on immunizations and obscures public health officials' understanding of vaccination coverage in real time.
In a statement, the Public Health Agency of Canada said it is collaborating with PAHO and working with federal, provincial, territorial, and community partners to implement coordinated actions. Those are focused on "improving vaccination coverage, strengthening data sharing, enabling better overall surveillance efforts, and providing evidence-based guidance".
Canada maintained its measles elimination status for decades because of high vaccination rates. Measles is the most contagious infectious disease known to mankind, but the measles vaccine is highly effective at preventing it. Coverage of at least 95 per cent (with two doses of vaccine) is required to prevent transmission.
Until recent years, Canada has maintained vaccination rates at that level. But vaccination rates have dropped in recent years across the country, especially since the pandemic. In Ontario, which saw the highest number of measles cases in the outbreak, just around 70 per cent of seven-year-olds were fully immunized against measles in 2023-24 compared with 86.1 per cent in 2019-20.
Sustained transmission of measles from person to person for 12 months is considered evidence that endemic measles has re-established in a country, said officials from PAHO. With Canada's loss of measles elimination status, the entire Pan American region also loses its status.
"This loss represents a setback," said Dr. Jarbas Barbosa, director of PAHO. But he noted that two countries - Venezuela and Brazil - both lost their elimination status and regained it about five years later.
"This is not the first time we have faced this situation. Today we have more experience and better tools and we will be able to achieve elimination again. Elimination remains one of the greatest public health achievements of our region. It is an achievement we can and must recover."
Other countries in the region are also at risk of losing measles elimination status, notably the U.S., which faces possible elimination as early as January. Still, officials with PAHO noted that outbreaks in the Americas represent less than eight per cent of all the measles outbreaks in the world.
Dr. Daniel Salas of PAHO said Canada continues to have good levels of vaccine coverage across the general population, but the outbreak has grown and spread largely in close-knit communities with low vaccination rates. More than 80 per cent of cases in the ongoing outbreak have been among those who were unvaccinated.
Public health officials have said that the source of the multi-jurisdictional outbreak that resulted in nearly 2,400 cases in Ontario before it was declared over in August was a Mennonite gathering in New Brunswick last fall. The majority of cases in Ontario were in a relatively small geographic area in southwestern Ontario.
Salas said governments in Canada are working to tailor their strategy to have a better approach to convincing people in these communities of the importance of getting their vaccines. That may also help other countries, he said. He also said there is a link between cases that have caused outbreaks in Canada, the U.S. and Mexico.
Canada can regain its measles elimination status if it goes 12 months without sustained transmission of measles.
The loss of Canada's measles elimination status comes at a time of spreading disinformation and misinformation about vaccines - some of it coming from health officials with the U.S. federal government, much of it disseminated online. It also comes at a time when public health units in Ontario are facing widening funding gaps that are hampering their abilities to do their jobs.
Health units play a key role in infectious disease surveillance and the prevention of spread. In Ottawa, without a reliable vaccination registry to track vaccine coverage in real time, public health staff painstakingly check individual students in certain grades every year to remind people to get vaccinated and to better understand vaccination rates. Students who don't have an exemption are required to be vaccinated to attend school in Ontario.
In Ottawa, public health staff are currently monitoring a handful of measles cases and have warned about possible exposures at a number of locations in October - including the Civic hospital emergency department.