Concern grows over low measles vaccination rates in parts of B.C.

Scientists are raising the alarm over low measles vaccination rates in parts of B.C. as concern grows over outbreaks in Ontario and Texas.

Health officials in Ontario say there have been 350 cases of the virus in the province since late October — with 173 of those infections reported within the last several weeks — and in late February, an unvaccinated Texas child lost their life in the first U.S. measles death since 2015.

The measles, mumps and rubella vaccine — which is safe and highly effective at preventing infection and severe cases — is recommended for children between 12 and 15 months old for the first shot, with the second coming between the ages of four and six.

However, the Okanagan and Kootenay-Boundary regions of B.C. showed less than two-thirds of seven-year-olds were up to date with their measles shots in 2023, the latest year on record, well below the recommended 95 per cent rate to achieve herd immunity.

Across B.C., as a whole, the percentage of seven-year-olds who were up to date with their shots has been dropping steadily for over a decade, and the province as a whole saw only 72 per cent coverage in 2023.

The province has thus far reported four travel-related cases of the virus this year, all of which are related to air travel to Southeast Asia.

Scientists say it's more imperative than ever that people check the vaccination status of their children, especially as measles is incredibly contagious and has high hospitalization rates for those who aren't vaccinated.

"I think we do have areas and school districts where there are enough unprotected children that measles could take off if it gets introduced here," said Caroline Colijn, a Canada 150 Research Chair in mathematics at Simon Fraser University.

Last month, Colijn and her co-authors published a modelling study on measles to see what happens when the respiratory illness is introduced to a community, and what level of vaccination coverage or previous immunity from infection is needed to prevent outbreaks.

The SFU scientist says that measles is so infectious that if there's an exposure in a room, anyone who's not immunized will go home with measles — and symptoms may not appear for seven to 10 days afterwards, making contact tracing difficult.

Jia Hu, the interim medical director for immunization programs at the B.C. Centre for Disease Control, says that while B.C.'s measles vaccination uptake looks low among children, actual rates are likely a bit higher given some residents may have just moved to the province and others are not registered in the provincial immunization registry.

Still, he acknowledges that rates are lower than where public health officials want them to be for the preventable disease — which was considered eradicated in Canada in 1998.

Hu says that the pandemic disrupted many childhood vaccine schedules, which could explain the downturn in vaccination rates. 

He added the data shows that many seven-year-olds in B.C. were eligible for their second measles shot at the peak of the pandemic.