Ag Days measles exposure has potential to be superspreader event in Manitoba: expert

Tens of thousands of people may have been exposed to measles during Manitoba Ag Days in Brandon last month. Danton Unger reports.

Manitoba is continuing to see a spike in measles cases that is carrying over from 2025, with concerns that numbers could balloon further after a potential superspreader event last month.

The province is currently leading the country, according to federal data, with the most cases since Jan. 24. Provincial data shows Manitoba has 74 confirmed cases of measles and eight probable cases since the beginning of 2026.

In 2025, there were 319 cases and 29 probable cases.

Another jump is also possible after Manitoba Health Ag Days, which ran from Jan. 20 to 22 in Brandon, was a recent exposure site.

A spokesperson for Ag Days confirmed 35,000 people attended the three-day event.

“It’s very concerning when you hear stories like that, because we know that measles is an extremely infectious virus,” said Dr. Philippe Lagacé-Wiens, a microbiologist at St. Boniface Hospital and an assistant professor in the department of medical microbiology and infectious diseases at the University of Winnipeg.

“We know, based on epidemiological data, that about 90 per cent of people who are susceptible to the measles virus who get into a closed space with an infected person will themselves become infected.”

• Ag Days and Winkler part of new measles exposure sites

Lagacé-Wiens said there is the potential for Ag Days to become a superspreader event, but he noted that can’t be determined until cases start to appear.

Dr. Davinder Singh, a medical officer of health for the Manitoba immunization program, confirmed to CTV News lab confirmed cases linked to Ag Days have already started to pop up.

“Given that, combined with the number of people attending and out of those, a proportion would probably be susceptible, meaning that they hadn’t previously had an infection or been immunized, then that just has the potential for lots of new infections.”

Given what has happened over the last year, how did Manitoba and Canada get to this point?

Measles was first eliminated in Canada in 1998, and between January 2000 and December 2024, there were only 18 cases in Manitoba.

That changed in October 2024, when rising measles cases started to appear around Canada. In November 2025, the country lost its measles elimination status.

Lagacé -Wiens said previous cases were imported cases — people coming into Manitoba and Canada — but given the country’s high vaccine uptake, the virus would die off.

That has since changed.

“What’s happened is that the virus made its way into a community where we don’t have adequate vaccine rates, so it’s quite easy for an individual who’s infected to meet up with somebody and transmit the virus to somebody that isn’t immunized,” Lagacé -Wiens said.

When asked why the situation has changed, Lagacé-Wiens said it’s multifactorial. The COVID-19 pandemic galvanized people who were previously resistant to vaccines, he noted, as some felt like the COVID vaccine was being forced on them. Secondly, he said the pandemic led to a lot of people staying home and not following up on their immunization schedules.

“Even if they were perfectly willing to get immunized or get their children immunized, they may not have been able to follow up on that for whatever reason,” he said. “So we know that there’s been a decline since the pandemic of immunization rates.”

Singh noted the vaccine being used in Manitoba is basically the same vaccine that was being used in the province in the 1960s.

“It has been extremely successful. It’s the only reason why we were able to eliminate measles in Canada. Before that point, it was endemic in Canada, just like many other countries. But we were able to get to the point where we had no locally circulating measles, and we went from many thousands of cases to a handful every year,” said Singh. “It has been a very effective, very well-known vaccine, so it isn’t anything new for Manitoba or for other places, but people, for different reasons, have lost trust in the vaccine and in the providers providing the vaccine.”

Lagacé-Wiens is hopeful Canada’s elimination status will return, but he knows it will take time. How much time it takes all depends on how Manitobans and Canadians respond.

“Bear in mind, you need to achieve two things: control of measles and no transmission for at least a year,” he said. “So it’s going to be a while before we get to that.”

If the vaccine uptake gains traction again and more people become immunized, Lagacé-Wiens said that status can arrive a lot sooner. However, if the other route is taken, of people getting infected and measles spreading through the population as herd immunity develops, it could take some time. That would be the much more dangerous option, he said.

“We’re talking at a very high cost, risk of hospitalizations, risk of long-term disability related to measles infections, risk of ICU admissions. Then there’s the less severe parts, days lost to looking after your children or looking after yourself, unable to work, things like that, being in isolation,” he said.

“So those are all both hard and soft impacts of allowing this disease to immunize people instead of using a perfectly safe vaccine.”

A timeline of measles in Manitoba

February 2025

Manitoba’s first measles bulletin for the year was released, highlighting four exposure sites at the end of January. The first happened Jan. 26 at Reinland Mennonite Church in Winkler, Man., while the other three were on Jan. 31 at the Health Sciences Centre.

There were five confirmed cases in February.

March 2025

The public was warned about measles exposure related to an international flight. On Feb. 26, public health said someone with measles travelled from Pakistan with their eventual destination being Winnipeg. The individual also had a layover in Toronto before coming to Winnipeg.

There was one confirmed case in March.

April 2025

Health officials said a bus servicing Southwood School, as well as the school itself in the Hamlet of Schanzenfeld, Man., were sites for measles exposure on April 14 and 15.

In total, there were 13 confirmed cases in April, as well as four probable cases in the province.

May 2025

Manitoba Health issued 10 measles updates in the month of May with exposure sites listed throughout the province, from places in Winkler and Boissevain to areas throughout Winnipeg.

The province also expanded the vaccine eligibility to include infants from six to under 12 months of age in the Southern Health and Interlake-Eastern health regions.

May saw a significant increase in cases, with 72 confirmed.

June 2025

There were another six updates shared in June, with the majority of the exposure sites happening in southern Manitoba. There was also an exposure at the Children’s Hospital in Winnipeg.

Manitoba Health said there were 28 confirmed cases and four probable cases.

July 2025

July had another nine measles updates. A Shoppers Drug Mart in Brandon, medical clinics in Morden and multiple businesses in Winnipeg were some of the exposure sites the public was warned about.

Cases climbed again in July with 49 confirmed and three probable.

August 2025

Only a pair of updates were issued in August, with Winkler and Morden the only impacted areas.

There were 28 cases and two probable cases in August.

September 2025

A Winnipeg school was an exposure site twice in September, being listed in two of the eight updates issued by the province.

Just like August, there was 28 cases in September with two probable cases.

October 2025

Of the four updates in October, locations in Portage la Prairie were mentioned multiple times, as well as a Dairy Queen and a school in Winkler, which had numerous exposures.

There were 23 cases and one probable in October.

November 2025

November was another busy month for Manitoba Health, with eight measles updates issued.

There were a number of Winnipeg exposure sites listed, including CF Polo Park, Landmark Cinema on Grant Avenue and a YMCA on Portage Avenue.

There were 24 cases in November, with six probable cases.

December 2025

December saw another jump in cases compared to the previous month, with 48 confirmed and seven probable.

In total, there were 11 measles updates shared by the province. Health centres, schools and churches throughout the province made up the majority of exposure sites.

January and February 2026

The start of 2026 was similar to how 2025 ended, with Manitoba Health issuing 13 more measles updates.

Exposure sites in Winkler and Morden accounted for most of the exposure sites listed in the updates.

So far in February, there have been three updates. The main concern shared was exposure at Ag Days in Brandon from Jan. 20 to 22.

As of the end of January, there are 74 confirmed cases and eight probable.

With files from CTV News’ Danton Unger