A measles outbreak Nova Scotia has risen to 30 cases in a northern part of the province with a low vaccination rate, health officials said Thursday.

All 30 cases originated from travel within Canada to regions where measles is known to be circulating, Nova Scotia Public Health said. The agency had reported a single case on July 7 in the northern zone.

Dr. Ryan Sommers, senior medical director of public health, said the new cases mainly involve large households and specific, small communities whose members are in close contact with one another.

“The risk to the general public is still considered low at this time,” he told a media briefing Thursday afternoon.

Citing the need to protect people’s privacy, Sommers declined to give details on the communities involved in the outbreak, including “if there are any religious affiliations that they have.”

“What we can say is, what we’re seeing in Nova Scotia, is these are low-vaccine communities.”

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Sommers thanked the communities involved in the measles outbreak for their co-operation with public health, saying they followed recommendations and “avoided any exposures outside of their households.” As a result, he said, there have been no new public exposure sites to report.

Some community members, he added, received an immunization within 72 hours of being exposed to the measles virus, but he declined to say how many.

Michelle Thompson, Nova Scotia’s minister of health, told reporters Thursday that the outbreak in the province’s north is “not unexpected.”

“We know there are some folks who are under-immunized throughout the province, and so when measles enters a population or … enters a community with lower immunization rates, we can expect to see more measles cases,” Thompson said.

She said it’s possible the number of cases in this community may “go up a bit higher.”

Sommers said it’s common for secondary infections to appear within seven to 21 days after initial measles cases are identified.

Eight of 30 cases in the northern zone have been lab-confirmed and the remaining are considered confirmed based on patients’ household exposure and symptoms.

Sommers said that so far these cases have not required hospitalization, and most people have been recovering as they self-isolate at home.

The provincial health agency is reminding Nova Scotians that the best protection against measles is vaccination, and every person born after 1970 should have two doses of the measles-mumps-rubella vaccine after their first birthday.

Sommers said the majority of those who have measles are young people “ranging from less than five years old up to (people in their) 20s and 30s.”

Nova Scotia’s Department of Health says 93.4 per cent of children who turned two years old in 2024 had received one dose of the measles vaccine, and 78.6 per cent were fully vaccinated with two doses. A spokesperson with the department says actual measles vaccination rates in Nova Scotia may be higher “because of under-reporting.”

Scientists, meanwhile, say that a population needs a vaccination rate of 95 per cent — with two doses — to stop measles from spreading.

Sommers said he was unable to provide a breakdown of the measles vaccination numbers for the northern health zone where the outbreak is located.

In May, a single case of measles was reported in the Halifax Regional Municipality, but there were no secondary infections identified with the original case, now considered “resolved.”

This report by The Canadian Press was first published July 24, 2025.