Can you get measles if vaccinated? What to know as cases rise

As measles cases continue to rise in Canada, last week brought an uncommon occurrence.

A fully-vaccinated 30-year-old teacher in Ontario contracted the highly contagious infectious disease. This event has drawn the attention of health officials, highlighting its rarity.

The man had close contact with students and teachers at a high school in the York Region, north of Toronto, and the case was likely related to community transmission, the region’s medical health officer said on Monday.

Although fully-vaccinated people can get measles, Dr. Sumontra Chakrabarti, an infectious diseases physician at Trillium Health Partners, stressed how infrequent it is.

“This vaccine is very good at preventing infection, but it’s not 100 per cent. It’s about 95- to 97-per cent effective,” he said.

“So there are going to be people who are fully vaccinated that still might get measles. It still does protect you against the more severe aspects of it.”

This particular case adds to the 17 reported instances of measles across Quebec, Ontario, Saskatchewan, and British Columbia as of Monday. More than half of these cases have been concentrated in the Montreal area.

Measles is one of the most contagious diseases in the world and is airborne. It is so contagious, Chakrabarti said if someone with measles exits a room, others can be infected up to two hours after that person has left.

“The best protection that you have is the vaccination by far,” he stressed. “(The measles) is an exceptionally, if not the most, contagious virus that we know in terms of identified human pathogens. If you don’t want to get infected, you should avoid crowded indoor spaces. But apart from that, it’s something that’s very, very difficult to avoid.”

The measles vaccine is available