Canada’s top doctor is calling on people to check that they’re fully immunized with two doses of the measles vaccine before heading out of the country.

Global health authorities are reporting a significant increase in measles in 2023 that continues, due in part to a decline in measles vaccinations during the pandemic.

“As we head into the spring break travel season, I am concerned that the global surge in measles activity, combined with the decline in measles vaccine coverage among school-aged children in Canada, could lead to an increase in imported measles cases, potentially resulting in transmission in communities in Canada,” Dr. Theresa Tam, Canada’s chief public health officer, said in a statement on Friday.

“I strongly advise everyone in Canada to be vaccinated with two doses of a measles vaccine, especially before travelling. If needed, measles vaccination should optimally be given at least two weeks before departure, but there are still benefits if given less than two weeks before travelling.”

Measles is no longer common in Canada, but outbreaks can happen when unvaccinated or otherwise susceptible people travel to and from countries where the virus is spreading between people. 

Measles spreads easily through the air, leads to high hospitalization rates and can cause a hacking cough, high fever and a prominent rash. In more serious cases, it leads to pneumonia, brain damage and death in up to three out of every 1,000 children infected. 

Infections can have wide-ranging and sometimes lifelong consequences, including blindness and deafness.

WATCH | Jump in measles abroad has Canadian medical experts concerned:

Two doses of the measles vaccine are considered to be enough for full protection in both adults and children.

The first dose of measles, mumps and rubella vaccine is usually given to babies at 12 to 15 months, and then again before the child starts school.

The Canadian Immunization Guide recommends that adults who don’t know whether or not they received two shots get a booster, especially if they’re travelling.

Public health officials across Canada say the COVID-19 pandemic emergency disrupted routine vaccination programs.

Dr. Isaac Bogoch, an infectious diseases physician at Toronto General Hospital, said while the vast majority of children are vaccinated to protect against measles, there are still pockets of the country that are under-vaccinated.

“It wouldn’t be surprising if we see imported cases leading to sporadic local transmission in the country, which is completely avoidable if we get everyone vaccinated with two doses,” Bogoch said.

The U.S. Centers for Disease Control and Prevention reports that as of Feb. 22, a total of 35 measles cases were reported by 15 jurisdictions: Arizona, California, Florida, Georgia, Indiana, Louisiana, Maryland, Minnesota, Missouri, New Jersey, New York City, Ohio, Pennsylvania, Virginia and Washington.

There were also 42,200 measles cases across more than 40 European countries last year, the World Health Organization said — a more than 40-fold increase from 2022, which saw fewer than 1,000 cases.