EDMONTON -- Alberta health officials have acknowledged the province has a hesitancy issue with the AstraZeneca vaccine.

If fully operational, the mass vaccination clinic in Edmonton at the Expo Centre can vaccinate upwards of 6,000 people per day, Alberta Health Services said. However, as of Thursday morning, just 413 were booked in for appointments after the site saw fewer than 250 patients the day before.

Michael Zakhary, an AHS medical officer of health in the Edmonton zone, said in an interview with CTV News Edmonton that there may be some level of hesitancy towards the AstraZeneca vaccine.

He added that some of it may be attributed to rare incidents of serious blood clotting occurring after people received the vaccine.

Alberta currently has a disproportionate amount of AstraZeneca in stock.

Of the 1.18 million doses of Pfizer and Moderna Alberta has received, more than 917,000 doses have been administered – or 78 per cent of available supply.

But of the 270,800 doses of AstraZeneca the province has received to date, less than 32 per cent has been used – fewer than 87,000 doses.

While AHS says AstraZeneca has a longer shelf life so there is less urgency to use it, officials are affirming its effectiveness and safety to help counter narratives about how often blood clots can occur.

BLOOD CLOTS ARE RARE

Zakhary told CTV News Edmonton that it is “very rare” for the AstraZeneca vaccine to produce blood clots and that they are treatable.

Research around the world shows the frequency of blood clots ranges from one in 25,000 doses administered in Norway, to one in 100,000 in Germany, to one in 1 million doses in the United Kingdom.

Those statistics are for people less than 55 years of age, Zakhary says.

“For that reason, Alberta has temporarily paused the AstraZeneca vaccine for people under the age of 55 just as a precautionary approach,” Zakhary said.

“It’s just a precautionary approach until further assessment to gather more information (and the) latest evidence to ensure safety.”

Otherwise, Zakhary said anyone who is 55 to 64 years of age is encouraged to get immunized.

“It’s safe. It’s effective… it's much safer to get immunized than to get COVID-19 as a disease.

“The risk for blood clotting with COVID itself is much higher than these very rare incidents.”

Canada has only confirmed one case of a blood clot linked to the AstraZeneca. The Quebec health ministry and Public Health Agency of Canada reported the case on Tuesday. According to officials, the Quebec women experiencing the blood clots is now recovering at home.

Zakhary says that officials are continually sharing information with each other to ensure that national and provincial guidelines remain as updated as possible.

“This is the nature of science and evidence,” he said. “It evolves and as we get more information, we make sure we follow (these) precautionary measures and approaches.”

Ultimately, COVID-19 immunization remains the most effective means to curb the spread of the disease, Zakhary said.

“All Albertans (should) get immunized as soon as they are eligible, no matter what vaccine is the option,” Zakhary said. “Every degree of protection counts, and we all need this degree of protection.”

ASTRAZENECA, LIKE ANY OTHER VACCINE, PROTECTS LIVES: HINSHAW

Dr. Deena Hinshaw, Alberta’s chief medical officer of health, said in her COVID-19 update Thursday that receiving a first dose of the AstraZeneca vaccine has been shown to reduce chances of infection by 60 to 70 per cent and hospitalization by 80 per cent – including against the B.1.1.7. variant that originated from the United Kingdom.

She added that in the U.K., 20.2 million doses of AstraZeneca vaccine were administered by the end of March. There were 79 blood clots reported.

“That means that 20,199,921 people benefited from the protection that their AstraZeneca vaccine gave them and did not experience this rare side effect,” Hinshaw said. “The (blood clotting) syndrome is very rare.”

Hinshaw said that the risk from COVID-19 infection for those aged 55 to 64 is “much greater” than any risk of blood clotting from the AstraZeneca vaccine.

For Albertans who are thinking of "vaccine shopping" or waiting until the vaccine of their choice becomes available, Hinshaw said they would be potentially risking exposure to COVID-19 – especially as cases continue to rise in Alberta and shipments of the Moderna and Pfizer vaccines are not expected until next month.

“While not getting vaccinated may feel like a way to protect your health by avoiding the rare risk of a blood clot following vaccine, waiting can actually increase your risk of getting sick or worse.”

“(If eligible) delaying getting AstraZeneca, is putting your health at increased risk during this time of waiting.”

‘BLOOD CLOTS HAPPEN MORE THAN MANY PEOPLE REALIZE’: HINSHAW SAYS

Hinshaw reminded the public that, in general, blood clots happen more frequently than people realize.

“By taking birth control medication, ibuprofen, and many other types of medications, we are also exposing ourselves to an increased risk of experiencing various forms of blood clots, except that risk... is very small, and because it is far outweighed by the benefits that come from getting the treatment or medication we need.

“The same principle applies for this vaccine. AstraZeneca has benefit; it is preventing infection and severe outcomes and the risks are rare,” Hinshaw said.

With files from CTV News Edmonton's Dan Grummett