Manitoba has decided to put a pause on offering the AstraZeneca vaccine to people under the age of 55.

Dr. Joss Reimer, head of our province's Vaccine Implementation Task Force says this pause is the result of some new information coming out of Europe. Dr. Reimer says despite the findings that there was no increased risk of blood clots overall related to AstraZeneca in Europe, a rare but very serious side effect has been seen primarily in young women on that continent.

"So out of an abundance of caution, Manitoba will be recommending that these vaccines only be used in people who are 55 and older at this time," says Dr. Reimer. "I do want to say that this is a pause, while we wait for more information to better understand what we are seeing in Europe."

Dr. Reimer calls this an important and evidence-based change that is being put in place in Manitoba.

"We have to respond to what we know when we know it in this vaccine campaign, which does sometimes mean adjusting our plans in real time," she says.

As a result, in Manitoba, AstraZeneca will only be used for people aged 55 to 64. The change takes effect immediately.

In Manitoba, AstraZeneca is available through medical clinics and pharmacies. To date, about 14,000 of the 18,000 doses received by our province have been used up.

"We are speaking with those partners today so that they can adjust their vaccine plans, which means that anyone under the age of 55, will be contacted to cancel their appointment," explains Dr. Reimer. "I know that this could be very disappointing news for people who were expecting to receive the vaccine."

For those who have already received the AstraZeneca vaccine, Dr. Reimer assures the public that to date none of the side effects have been identified in either Manitoba or Canada. It is estimated that somewhere between 1 in 100,000 to 1 in a million people who receive this vaccine will notice symptoms between four and twenty days after immunization. Dr. Reimer says symptoms can mirror a stroke or heart attack.

"Whether or not you have had the vaccine, if you are having symptoms that look like a stroke or a heart attack you should seek immediate medical attention," she stresses.

Meanwhile, Dr. Reimer says at this time, the benefits of the vaccine for people between 55 and 64 years of age still outweigh the risks.

"Because the serious side effect has been appearing more often in younger people and at the same time for people who are older than 55, the risk of COVID infection goes up substantially," she explains. "We know that when people are hospitalized due to COVID, they have a very high risk of having a blood clot. So the higher the risk is related to COVID, the more beneficial that vaccine becomes, even if there is a risk of blood clots associated with it."

Dr. Reimer says it is also not certain whether this side effect is more common in women than men. She notes there are far more women than men in health care. And, with more women than men receiving vaccines, that could be why these side effects are showing up in women, and not men.

"We want this vaccine program to be safe and while we still believe that probably the benefits for all ages outweigh the risks, I'm not comfortable with 'probably'," says Dr. Reimer. "I want to see more data coming out of Europe so that I know exactly what that risk benefit analysis is."