Here's what we know so far about B.C.'s response to AstraZeneca vaccine concerns

British Columbians learned Monday that health officials are pausing the use of AstraZeneca-Oxford vaccines in people under the age of 55 in response to a rare condition that's been reported in Europe.

Similar measures are being taken across Canada in response to recommendations from the National Advisory Committee on Immunizations (NACI).

Provincial Health Officer Dr. Bonnie Henry explained that when public health picks up signals of possible risks from these relatively new COVID-19 vaccines, there's a responsibility to dig further into the data.

"It is unlikely we will see any cases here in British Columbia or in Canada. But it is also a condition that we have a test for and there is treatment," Henry said.

Here's what we know so far about B.C.'s response:

What's the issue?

In a small number of cases reported in Europe, people have developed serious blood clots after receiving an AstraZeneca-Oxford COVID-19 shot. Some of those cases have involved cerebral venous sinus thrombosis, a type of clot that affects the brain. Those affected have mainly been women under the age of 55.

Henry said fewer than 30 cases of what's being called Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) have been reported to date, but the condition is quite serious.

According to NACI, the fatality rate is currently estimated at about 40 per cent, but that could fall as people become more aware of the condition and seek treatment.

What is B.C.'s response?

B.C. is following NACI's advice and suspending the use of the vaccine in people under the age of 55.

"This is our safety system working across the world and in Canada. It means that we are taking immediate action when we detect a signal to protect health," Henry said.

How long will this last?

It's too early to say for sure, but Health Canada is asking the vaccine's manufacturers for more data before deciding what to do next. The federal body has also requested risk assessments broken down by age and gender.

For B.C., answers about the next steps are expected to arrive relatively quickly.

"We anticipate that we will have more information in the next two to three days," Henry said.

Will this affect the age-based rollout of COVID-19 vaccines in B.C.?

There should be no impact in the near future, Premier John Horgan said Monday.

"We had not calculated AstraZeneca into any of our thinking with respect to age cohorts," he said, adding that large amounts of the Pfizer-BioNTech and Moderna vaccines are still expected to arrive soon.

How has B.C. been using the AstraZeneca-Oxford vaccine?

Since the first doses began arriving in the province in mid-March, B.C. has been using AstraZeneca to protect workers in specific industries where it isn't always possible to have barriers between people or full personal protective equipment. That includes places like food-processing plants, large industrial camps and farms where workers live in group housing.

Beginning in April, the plan was to deploy the shot to front-line workers including teachers, child-care workers, first responders, grocery store workers, people who work in manufacturing, warehouse workers, postal workers and those living in group housing at places like ski hills.

How does this pause affect that plan?

Vaccine clinics for front-line priority workers are organized by employers, so the exact response may differ depending on the workplace.

The B.C. government says older workers can still get the shot, but some employers are pausing their immunization plans entirely — not just for people under the age of 55. LNG Canada, for example, told CBC News that it will wait for further instructions from health authorities before resuming any shots at its construction site in Kitimat.

Meanwhile, at least one group is receiving alternative vaccines. Teachers in Surrey, who have received early access to the shot because of the high risk of infection in the area, were scheduled to receive Pfizer shots on Monday, according to school district superintendent Jordan Tinney.

Should people who've received their first dose be concerned?

Henry said that anyone who received a shot of AstraZeneca more than 20 days ago should not be worried about VIPIT.

The window for this serious condition to develop is believed to be between days four and 20 after getting the jab, and anyone who develops symptoms should seek immediate medical attention.

What symptoms should people be aware of?

VIPIT results in stroke-like symptoms including shortness of breath, chest pain, leg swelling, persistent abdominal pain, sudden onset of severe headaches, blurred vision and bruising in places apart from the injection site.

What about second doses of AstraZeneca for workers who've already received one?

Again, it's too early to say, but Henry is optimistic, given the long gap B.C. has implemented between first and second doses.

"It is very likely that second doses will be available, but we have time between now and three to four months to understand the implications of this," she said.

What happens to the AstraZeneca vaccine doses that B.C. has now?

B.C. currently has "very little" left of the vaccine, and Henry said officials will make a decision over the next few days about what to do with it. However, Canada is expected to receive another 1.5 million doses of AstraZeneca from the U.S. on Tuesday.

"It is possible that we may need to use this vaccine in people where we know this rare event is not likely to happen," Henry said, referring to people over the age of 55.