Doctors, virologists warn against attending large public gatherings if not vaccinated against measles

With the number of measles cases rising in Manitoba, experts caution people who have not been vaccinated against the disease to avoid large public gatherings until the outbreak subsides.

The warning comes after the Manitoba government said people who attended Ag Days Indoor Farm Show in Brandon He might have been infected with measles at the end of last month.

About this 35,000 people participated The annual event takes place at the Keystone Center in the southwestern Manitoba city between January 20 and 22. People visiting hotels, restaurants and stores in the city during the three-day event were also possibly exposed to the virus, according to Manitoba Public Health.

“It’s absolutely scary,” said Dr. Philippe Lagasse-Viens, a medical microbiologist and physician at St. Boniface Hospital.

“In an enclosed space, if there’s an infectious person and they go into that room, 90 percent of susceptible people will contract measles.”

Sometimes the symptoms of measles begin to become physically apparent a few weeks after being infected, and a person suffering from the disease may spread it unknowingly.

“This chain of transmission is going down when you have that many people exposed. It’s very worrying,” he said.

In January, Manitoba records highest monthly number of confirmed measles cases The outbreak began in February 2025.

As the disease continues to spread to this extent, people in larger groups are more likely to be exposed to the disease, and people who have not been vaccinated are more likely to be infected, Lagasse-Viens said.

Measles can persist in the environment for hours after an infected person has been somewhere, and Lagasse-Viens said that unlike COVID-19, physical distancing or masks do little to protect someone from contracting it.

“The really big message is that if you haven’t been vaccinated against measles or you have any measles-like symptoms, don’t go to these festivals,” he said.

Lagasse-Viens said the same message should also be conveyed by event and festival organisers.

Visual cues that remind people how measles can spread at large events, and the importance of staying home if symptoms are present, are an option, she said.

Now is not the time for restrictions

Angela Rasmussen, a virologist and lead scientist at the Vaccines and Infectious Diseases Organization at the University of Saskatchewan, said herd immunity is no longer an option to protect unvaccinated people from the virus.

He said the only opportunity to prevent the risk of infection is to reduce the probability of exposure. Measles is more contagious than other diseases partly because you have to be exposed to less of the virus to become infected.

The recommendation is that, for example, newborns who are not yet eligible for vaccination or children who have not received the measles shot, even if it is because they are immunocompromised, should avoid large public gatherings, Rasmussen said.

“It’s really unfortunate that parents have to make these choices, but that’s what happens when vaccination rates get this low.”

According to Dr. Lagasse-Viens, the measles outbreak in Manitoba has not reached a point where restrictions or event cancellations would be required to control the spread.

“If we start to see situations where babies are crammed into intensive care units and putting a strain on hospital systems… then we may start to see public health placing an emphasis on reducing the incidence,” he said.

On the heels of the COVID-19 pandemic — where widespread isolation measures and vaccine policies sparked a public backlash — there is even less appetite for restrictions around measles, and Lagasse-Viens said that for the time being, vaccination alone is still a solution to curbing the number of measles cases.

But given the possibility of a major outbreak of the virus, stricter measures cannot be completely ruled out in the future.

“If people don’t really roll up their sleeves and get vaccinated, that’s always a possibility,” Lagasse-Viennes said.

“I don’t see any way out of this uncontrolled measles transmission for at least a year or more at this point unless we really take an honest look at our vaccine rates,” he said.

Rasmussen said there are continued efforts by disinformation campaigns to undermine public health advice on vaccination, making it really hard for experts to push for measles vaccination among people who have not yet received the vaccine.

At this stage, he said, health officials need to find a strategy that is more effective and aggressive against misinformation.

“We need to reach out to people who are undecided about vaccines and find a way to communicate directly with them,” he said.

Follow public health guidance

Brandon Mayor Jeff Fawcett said the city is monitoring potential measles exposure on AG days, but the province has not yet advised of any increase in local cases.

Measles has not been a significant public health issue in Brandon, Fawcett said. He attributes this to high vaccination rates because a large number of residents in the city lived through the Canadian measles outbreak in the 1980s.

He said, “Our parents didn’t think twice about making sure we were taken care of by our science. It’s well understood, and we have a lot of people of that generation.”

For now, Brandon is following the lead of Manitoba health officials, reminding people of the availability of vaccinations and encouraging residents to monitor themselves for symptoms.

He said restrictions on gatherings would be imposed only if public health officials recommend it.

“We also have other programs going on and we are not taking an aggressive approach in this,” he said. “Life continues here. People take care of their health.”