By Tyler Choi

TORONTO (Reuters) – A measles outbreak in Vancouver that has infected nine individuals since Feb. 15 has led officials in the western Canadian city to urge the unvaccinated and under-vaccinated to be immunized.

Bonnie Henry, provincial health officer of British Columbia, told Reuters on Tuesday that being under-vaccinated would include people who have had only one measles shot, when two doses are required for long-term immunization.

“I do fully expect that we will see more cases related to this outbreak because of so many contacts with very highly infectious young people,” she added.

Henry said the outbreak originated from a family that visited an overseas country with a child who was not immunized and contracted measles. When the child returned to Vancouver to attend school, other students became infected.

Vancouver Coastal Health said measles had affected eight individuals in relation to the child, and one person in an unrelated case. Both were from last week.

Measles is a contagious disease that spreads through air and does not require direct contact. A measles outbreak has also stricken at least 225 people in New York state since October.

Henry said previous cases of measles in the province include one in 2014 in which 400 people in the Fraser Valley were infected, and one after the 2010 Vancouver Olympics from people visiting from overseas.

“It’s a wake up call for us to know that these vaccine preventable diseases are still around in the world and it is incredibly important for us to immunize all children,” she said.

(Reporting by Tyler Choi; Editing by Dan Grebler)