VICTORIA -- B.C.'s Ministry of Health is asking British Columbians who received an AstraZeneca vaccine in a pharmacy to ignore any invite they receive through the province's vaccine registration system to book an appointment for what the system thinks will be their first vaccine.

More than 200,000 B.C. residents have received an AstraZeneca vaccine, including tens of thousands who got one at a pharmacy, a process that did not require them to book through the province’s vaccine registration portal. Now, in an apparent glitch in the system, many of those same people may receive electronic invites through the central registry to book a first dose of the Pfizer or Moderna vaccines.

But the B.C. Ministry of Health is asking those who got the AstraZeneca vaccine not to book that appointment.

"If you received your first AstraZeneca shot in a pharmacy and have been invited to book a first dose through the provincial system, do not book the appointment," reads a statement from the ministry.

It's unclear how the province is tracking who got doses in pharmacies and how that information will be added to the central registry.

"If you have some people vaccinated through one program versus another and making sure you match people and get them at the correct moment - to me that's a logistics question," said Heidi Tworek, an associate professor in the School of Public Policy and Global Affairs at UBC.

B.C.'s immunization program is about to kick into high gear. In May, the province is set to receive more than a million vaccine doses, a record number for a one-month period.

Last week, Health Minister Adrian Dix said the key to moving swiftly through the program will be to sign up on the provincial Get Vaccinated website. 

"We want everyone to be ready to register – so register, register, register,” he said.

Everyone 18 and older can register. Those in their late 50's will be able to book vaccine appointments through the central portal this week.

"I hope what we will see is a very smooth rollout as we … vaccinate down through the age-eligible groups,” said Tworek. “That would be ideal.”

The distribution of the AstraZeneca vaccine through pharmacies happened on a first-come, first-served basis, initially for people 55 and older, and later for younger age groups. AstraZeneca was also offered at pop-up vaccine clinics in high-transmission neighbourhoods, which offered shots to residents without requiring an appointment.

Tworek said these AstraZeneca programs may have had a negative impact on people’s perceptions of the province’s vaccine distribution system.

Fraser Health has said it is no longer using the pop-up system after long lineups, people waiting for hours only to be turned away, and reports of people who shouldn’t have been eligible receiving vaccines. 

"How have the different pop-up style programs led to the feeling this is a rumour-based system, even though so much of it is a pretty-well-run, age-based system?" Tworek said.

That's even more of a concern, she says, as studies in the United States show that many of those at highest risk to contract COVID-19 aren't sure how to access the vaccine.

"Making sure people have access (and) they understand how to get the vaccine, I think, is a really crucial part of the puzzle,” Tworek said.

Key to that, she says, is to meet people where they are with information in various languages, in different neighbourhoods and perhaps even at special times, especially for shift workers.