CALGARY -- A walk-in vaccination clinic set up at the Telus Convention Centre reached capacity just an hour after opening on Tuesday but more slots were added as thousands of Albertans lined up and logged in on Tuesday to receive the AstraZeneca shot.

Albertans born in 1981 and earlier are now able to walk in to the largest mass vaccination site in the province at the Telus Convention Centre as part of the effort to get the AstraZeneca vaccine distributed quickly.

Before Tuesday, the only Alberta Health Services clinic to accept walk-ins was located at the Calgary office building on Southport Road in the southwest.

Signs set up about 10 a.m. said the clinic had reached its daily walk-in capacity limit. Then AHS sent out a tweet about 11 a.m. saying an additional 500 doses are being provided for walk-ins on Tuesday, which will be handed out on a first-come, first-served basis.

Walk-ins are available from 9 a.m. to 5 p.m. until April 23.

As of 4:30 p.m., AHS says 36,000 Albertans had booked in to receive a vaccine, including 8,496 in the Edmonton Zone and 20,267 in the Calgary Zone. About 1,500 people also attended walk-in clinics in Edmonton's Expo Centre and Calgary's Telus Convention Centre.

"This is an incredible increase in uptake for the AstraZeneca vaccine and we are pleased that so many Albertans took advantage of the increased eligibility criteria to book their appointment through AHS," read a statement. 

"For context, 4,525 people received the AstraZeneca vaccine in Edmonton, and 5,559 people received AstraZeneca in Calgary, between April 12 and April 18.

AHS says if has added staff at both walk-in sites to meet demand.

Vaccine appointments can also be booked through participating pharmacies.

The Telus Convention Centre location is accessible by C-train and tickets are being offered to transit riders — free parking is also available.

The mass vaccination clinic has capacity to operate 120 stations to administer the injections, although it had been reporting low traffic since opening two weeks ago.

Appointments pre-booked at the Telus Convention Centre are still being honoured.

Appointments for recently lowered minimum age of eligibility specifically for the AstraZeneca vaccine can still be made by calling Healthlink at 811 or through its online booking service.

Several infectious disease experts have spoken publicly in support of the decision to expand the vaccine to younger Albertans, saying that infection and hospitalization rates are increasing among people in their 40s and 50s.