EDITOR’S NOTE: This article has been updated to reflect that while a blood test can be used to detect if an individual has had the measles vaccine, public health guidelines are that most people do not require this.
Two companies that supply measles vaccines to Canada say they are running short on doses.
The disclosure comes as the highly contagious infection is spreading across the country and with health authorities strongly advising Canadians to be fully vaccinated against the disease, especially before travelling.
Pharmaceutical giants Merck and GlaxoSmithKline (GSK) posted reports to Canada’s drug shortage website showing they are experiencing shortages for their MMR vaccines used to vaccinate against measles, mumps and rubella, with remaining doses reserved for public immunization programs.
The companies both cite “demand-increase for the drug” as the reason why. Merck’s posting shows remaining doses of its MMR II vaccine are “reserved for the public immunization program.” GlaxoSmithKline’s states the same for its Priorix shot, saying “supply (is) unavailable in the private market.”
Merck’s filing shows the company expects the shortage to end in nearly a month on April 19. GlaxoSmithKline’s estimated end date is “unknown.”
Merck also reported an anticipated shortage for its MMRV jab ProQuad, which also inoculates against varicella virus as well as measles, from March 22 until April 19.
The reduction likely only affects people seeking to get another dose ahead of travelling though the shortages come as measles has been spreading in Canada.
“It’s that extra supply that we’re now getting for people who are saying: ‘Well, I’m going to Europe and I know there’s a lot of measles in Europe. And gosh, I can’t remember, did I get a second shot, did I not?,’” Dr. Gerald Evans, the division chair of infectious diseases at Queen’s University, told Global News.
“One of the groups of people that we’re very concerned about are adults now who were born in the 1970s,” he said. He notes that’s because people born before that may have already caught measles and survived, giving them immunity, and because people born after likely have two shots, making them fully vaccinated.
Health Canada told Global News in an email Friday that “Canadians can be assured that there are enough measles vaccines to sustain existing and increased public vaccinations.”
Both Merck and GST have advised Health Canada that they are able to fully meet demand for MMR vaccines, the agency says.
“There is currently sufficient supply of measles-containing vaccine and post exposure prophylaxis available to support outbreak management and targeted campaigns in response to measles importations and case management,” Health Canada said.
The agency added that Merck’s reported shortage only impacts the private market, which “makes up an extremely small portion of the overall demand.”
Health Canada says GSK’s shortage report was posted “as a means to proactively and transparently communicate their inability to meeting any new increased demand from the private market.”
“Health Canada and Public Health Agency of Canada are working closely with manufacturers, provinces and territories and stakeholders across the healthcare system, to monitor the supply situation,” the agency said.
The federal government declared it eliminated from Canada in 1998 after an immunization campaign, but last week Public Health Ontario said there were more confirmed cases in 2024 than in all of last year, rising from seven in 2023 to eight as of March 13. Quebec has reported 29 cases as of March 20. Other provinces including Saskatchewan and British Columbia have also reported infections.
Evans said Canada has always seen the occasional travel-related case because people not fully vaccinated will contract it while abroad.
What the country is seeing this year, he said, is the result of a “marked reduction” of measles vaccinations, especially of children.
“A lot of that is due to the unfortunate spin-off that we had from COVID with the anti-vaccination groups taking on the COVID vaccines,” he said.
Evans said the spread now among people who haven’t travelled shows “the virus is sneakily kind of working its way into the population,” which “really creates a circumstance where we become worried that we’re now going to begin to see outbreaks of measles.”
But because of high Canadian inoculation rates, he said it’s not likely Canadians will have to worry about excessive public health measures.
Two vaccines doses provide nearly 100 per cent efficacy, according to Health Canada.
The vaccine is administered as a two-shot series, with the first shot given at around 12 to 15 months of age and second shot at 18 months or between ages five and six years (before your child starts school).
The World Health Organization said COVID-19 disrupted many vaccinations globally.
On March 19, the WHO director of immunization Kate O’Brien said it is “really critical” to catch up.
More than 50 countries reported “large and disruptive” measles outbreaks in the past year, which is twice as many as the year before.
And he said it is so infectious that one person with measles can infect 18 susceptible people, compared to COVID-19’s three or four.
“Measles is one of the most highly communicable infectious diseases, and can very easily spread to other people if they are susceptible,” Health Canada previously told Global News.
Dr. Allan Grill, the chief of family medicine at Markham Stouffville Hospital, outside Toronto, said local and provincial public health authorities reassured him they have enough supplies.
“We aren’t seeing those shortages in our office. And I haven’t heard of it being in a problem among my colleagues, at least in my region and in York region,” he said.
He said they’re focusing mainly on kids who fell behind in vaccinations during the pandemic and people who aren’t sure if they have two doses.
If a patient is unsure about their measles vaccine status, it is preferred to administer an MMR vaccine to catch them up as opposed to ordering a blood test to verify their immune status. Giving an extra dose of an MMR vaccine to a person who may be fully immunized but isn’t sure is safe.
In a statement to Global News Thursday, Merck said it is aware of the shortage and is working to “provide a consistent supply of (its measles vaccines) in a timely manner.”
“From a global perspective, current demand exceeds available capacity and we are prioritizing our existing commitments,” GSK said in a statement.
“MMR vaccines are complex, and the lead time makes it challenging to scale up quickly when an urgent need arises. We expect this situation to continue throughout 2024 and 2025,” though GSK said it continues to meet the public market demand for Priorix.
Health Canada did not respond to a request for comment by deadline.
— with files from Global News’ Katie Dangerfield, Gabby Rodrigues and Katherine Ward, Reuters’ Jennifer Rigby and The Associated Press