Doctors say some Sask. adults might need measles booster shots

Saskatchewan adults might not have sufficient immunity to the latest measles outbreak and are being asked to check their vaccination records and get a booster shot if needed.

Cases of measles, which is highly contagious and can lead to serious complications, have been on the rise across Canada recently and there were three cases in Saskatchewan in March.

Although the Saskatchewan Health Authority (SHA) is recommending people check their vaccination records, there is one catch — the SHA doesn't have childhood immunization records for anyone prior to 1978.

"It can be really confusing if you don't have access to those records," said Ryan Meili, a family doctor practicing in Saskatoon. "Maybe you have a history of being told when you were a kid you had measles, but it was never documented." 

Anyone born between 1970 and 1996 needs a booster shot to be fully protected against measles, according to guidance Meili said the SHA has given doctors.

That's because the protocol during those years was for just one dose of the vaccine and Meili said studies have shown two doses, the standard since 1996,  provides better protection against catching and spreading the virus. 

"The first dose did decrease the transmission. But then getting that second dose into the schedule really did the trick," Meili said.

Joseph Blondeau, head of Clinical Microbiology at Saskatoon's Royal University Hospital and provincial lead for clinical microbiology with the SHA, said parents should also make sure their children are up to date on their vaccinations.

According to the province, only 75.5 per cent of Saskatchewan children received both recommended doses of the Measles Mumps and Rubella (MMR) vaccine by their second birthday in 2024.

Blondeau said that number should be closer to 97 per cent to achieve herd immunity, which is when enough of the population is either vaccinated or has acquired immunity to prevent disease spread.

"Measles is a highly, highly, highly contagious virus,"  Blondeau said.

"If you've not been immunized, the recommendation is for two doses. If you're partially immunized, the recommendation is for a single boost." 

Anyone born before 1970 is considered immune.

That's because measles infections were so widespread prior to public vaccination programs, that anyone alive prior to 1970 is presumed to have caught the disease and acquired lifetime immunity.