CALGARY -- Darcy Cairns is now fully vaccinated against COVID-19 and has the vaccination card showing the dates he received his two Moderna shots to prove it. 

The Calgarian received both doses in the United States and says he was surprised he wasn't asked about it at all when he and his wife drove back to Canada after spending six months in Arizona.

"At no time were we ever asked about our vaccines or if we were vaccinated," Cairns told CTV News while in his mandatory quarantine period in Calgary.

"Even with the follow-up calls they're doing to check and make sure we're in our quarantine, there was never any mention or ask if we were vaccinated."

Cairns knows he isn't alone. He says all of the Canadians he talked to while in the U.S. planned on getting the vaccine before returning home — but it turns out public health agencies don't know how many Canadians have done so. 

The Public Health Agency of Canada (PHAC) says data about travellers returning with the vaccine doesn't exist.

"Most information compiled nationally by PHAC comes from provinces’ and territories’ health authorities" reads a statement from the PHAC.

"Canadians have no obligation to report their out-of-country vaccination to PHAC, but might share with their family doctors or local health units."

Alberta Health says it does not have a breakdown of how many people who have received a vaccine out-of-province. 

In April, Canada's Chief Public Health Officer outlined possible scenarios for lifting health restrictions across the country based on vaccination uptake. Dr. Theresa Tam said public health measures could be lifted this summer if 75 per cent of Canadian adults receive the first dose of the vaccine and 20 per cent receive their second.

"If they don't truly know how many people are vaccinated, how are you going to accurately get to the number of percentage of people vaccinated to open up or know what the next steps are?" said Cairns, who worries he won't count towards the Canadian vaccination total because he received his shots elsewhere.

Canadians getting vaccinated in the U.S. a 'messy issue': Health experts

Canadians heading across borders to receive a vaccine can cause confusion for health officials back home, but it's not something that shouldn't be considered for people who have the means to do so.

"On the one hand, I do think there are problems with equity and access — not everyone has this opportunity," said Timothy Caulfield, Canada research chair in health law and policy at the University of Alberta.

"On the other hand, I love the idea of just getting vaccines into people's arms," he said. 

Though there's no exact number, there are several examples of Albertans receiving their COVID-19 shot in another country and some programs are backed by provincial governments. 

Premier Jason Kenney has also encouraged Albertans who are in the U.S. to get a vaccination if possible.

Hundreds of Albertans waited for hours to receive a dose supplied by the Blackfeet Nation in Montana and about 2,000 Alberta truckers who cross into the U.S. will get a shot thanks to a partnership between the province and Montana Government.

The truckers who receive a vaccine will have their Alberta Health records updated, but the doses won't count toward provincial vaccine statistics. 

"It does add to the confusion, both from the monitoring perspective — and I mean that from the public health side of the equation — but also from a policy perspective," said Caulfield.