EDMONTON -- Alberta's top doctor says it's very likely that second doses of COVID-19 vaccines will be offered within less than four months of the first as supplies ramp up.

The province authorized a 16-week interval in order to get as many people protected with their first shots as possible while vaccine shipments remained uncertain. For Pfizer-BioNTech and Moderna vaccines, the drug makers say the gaps between doses should be three weeks and one month, respectively.

“I want to be clear that that four-month interval was always a maximum,” Dr. Deena Hinshaw said Thursday.

“We were never planning to require a wait of four months. It was really about we would not have anyone go beyond four months, but if we can offer it sooner, we will.”

People on immunosuppressive drugs, like chemotherapy, are already being offered their second shots in a shortened time frame, Hinshaw said.

She noted that for the Oxford-AstraZeneca vaccine, there is evidence that a 12-week wait between doses is more effective than a shorter interval.

As of Monday, all Albertans born in 2009 and earlier will be able to book their first shot.

On Thursday, some 100,000 people born in 1991 and earlier booked their first vaccine appointments. After that, the province will be able to start offering followup doses, Hinshaw said.

So far, 1.73 million doses of vaccine have been given in Alberta.

Alberta recorded 2,211 new COVID-19 cases and no new deaths on Thursday. There were 654 people in hospital, including 146 in intensive care.

More than 11 per cent of tests came back positive.

Hinshaw also reiterated that the province is no longer testing every positive COVID-19 swab for variants. Instead, labs are testing a representative sample.

“This frees up crucial lab capacity to ensure that people get their COVID-19 test results back as soon as possible, which is the most important thing we can do with our lab capacity to minimize further transmission.”

She added that anyone with a positive test should assume they have contracted a variant, as variants are now dominant in the province.

This report by The Canadian Press was first published May 6, 2021.