Ontario's measles outbreak is so big, even New York health officials are taking notice

Ontario's measles outbreak has become so big that public health officials in New York state have included the province in a travel advisory that urges residents to get vaccinated before visiting.

"Measles is only a car ride away!" reads the April 2nd measles travel advisory for all New Yorkers from the New York State Department of Health.

"Currently, measles outbreaks are happening in parts of the United States and Canada, especially in Ontario, and around the world."

The advisory also lists the following countries as having a high number of measles cases: Yemen, Pakistan, India, Thailand, Ethiopia, Romania, Afghanistan, Indonesia, Kyrgyzstan and Vietnam.

"Measles is a highly contagious virus. Around 90 per cent of people who are exposed to a person with measles will become infected if they are not vaccinated. Because measles is so contagious, it easily crosses borders," the advisory continues.

The advisory notes that Canada's outbreak includes more than 600 cases with the majority located in Ontario.

According to Public Health Ontario, a total of 655 confirmed and probable measles cases have been reported in Ontario this year as of April 2. Of this total, 560 are confirmed and 95 are probable.

Infectious diseases specialist Dr. Isaac Bogoch said most of the province's cases are in southwestern Ontario. 

"The key thing to remind ourselves is that this is largely and almost exclusively in unvaccinated cohorts and currently is predominantly in southwestern Ontario — but people move, people travel and they can bring the virus with them," Bogoch told CBC's Metro Morning on Tuesday.

"We haven't seen this many cases per year in about a decade and it's only April," he said. 

Ontario's Ministry of Health said in a statement on Tuesday that the provincial government and Dr. Kieran Moore, the province's Chief Medical Officer of Health, have been clear in their messaging on measles to residents.

"Vaccination is the most effective way to limit the spread of measles and protect yourself and your loved ones," the ministry said.

"Children who are fully vaccinated with two doses are nearly 100 per cent protected. Over 96 per cent of cases in Ontario are among individuals who are unvaccinated."

The ministry said it is continuing to work with local public health units to make sure residents are up-to-date on their measles vaccine to limit further spread.

'We want to inform the public': public health director

In the travel advisory, N.Y. officials urge residents to ensure they are fully vaccinated against measles before travelling to another country or an area in the U.S. where there is an outbreak. It says the best way to protect against measles is to ensure that immunizations are up to date with the mumps-measles-rubella vaccine.

With spring and summer travel season coming, the advisory says people who are not protected can pick up the disease while travelling and spread it once they get back home. 

"Large measles outbreaks are possible when measles cases reach at-risk populations with low immunization rates against measles," the advisory reads.

Hannah Busman, Director of Public Health for Franklin County, N.Y., which shared the advisory, said in an interview that the public needs to be aware of measles outbreaks before traveling.

"We want to inform the public and have them have all the information before spring, summer comes up. Any time there are risks like this, the travel advisory does go out so people are prepared," Busman said.

'Measles can be a serious disease,' N.Y. official says

In an April 2 news release, N.Y. officials say travelers should plan to be fully vaccinated against measles at least two weeks before departure. The department recommends two doses for immunization.

"Measles is more common in different places and exposure during travel is something we need to consider," state health commissioner Dr. James McDonald said in the release.

"Measles can be a serious disease. It is not just a rash; it can cause pneumonia, hospitalization and even death."

The release says the total number of measles cases in the U.S. in the first three months of 2025 is already greater than the total number in the U.S. in all of 2024.

As of March 26, 483 measles cases have been reported in the U.S., with the majority in New Mexico and Texas. 

In the release, N.Y. officials added: "A deluge of vaccine misinformation in recent years has eroded public trust in vaccines, contributing to a rise in vaccine hesitancy and declining vaccination rates.

"Additionally, the pandemic may have caused people to fall behind on vaccinations. However, due to the seriousness of measles, the Department encourages everyone to get the MMR vaccine."

Measles symptoms include high fever, cough, runny nose, small spots with white centres inside the mouth, sore eyes, sensitivity to light and a red blotchy rash.