EDMONTON -- Alberta's top doctor reported 11 more confirmed cases of the COVID-19 B.1.1.7 variant on Thursday, including seven that contact tracers haven't been able to link to travel and two others in additional Calgary schools.

In total, four Calgary classrooms have been the site of potential variant exposures. Two were identified earlier in the week. The newest two cases are travel related.

While the students had entered isolation as soon as labs confirmed the positive test results, Alberta's top doctor said with confirmation of the two newest variant cases as the B.1.1.7 strain, families were now being offered extra testing.

Altogether, the province has found 68 cases of the mutations first found in South Africa and the United Kingdom.

When asked if the B.1.1.7 strain was definitively being spread in the community, Chief Medical Officer of Health Dr. Deena Hinshaw confirmed some cases had been found in "additional locations."

"That is, of course, concerning, but I do need to remind all of us that we are currently able to test almost every single positive COVID case for variant strains and so that does help us detect more that are out there so that we can contain them," she said.

"Again, we have seen in several cases that while we've identified the variant, we have not seen further spread onward because of the interventions that are in place."

She said that was true so far of the two Calgary schools with B.1.1.7 exposures earlier that week.

Given the variant cases account for a small proportion of Alberta's overall active cases, Hinshaw said they did not affect Alberta's plans to take the first step in reopening on Monday.

DAYCARE VARIANT CASES NOW 4: AHS

The number of variant cases connected to an Edmonton-area daycare outbreak has risen to four, Alberta Health Services told CTV News Edmonton on Thursday. AHS spokesperson Tom McMillan said testing was still underway of anyone who may have been exposed.

According to a staff member at the Tot Spot Academy in St. Albert, the daycare was advised it could stay partially open but decided to fully close out of an abundance of caution for 10 days from Jan. 21 to Feb. 1.

All child cohorts have returned except for the ones exposed to the variant cases, and those children will have to be retested before returning. Children who already returned were tested again, too.

The worker noted a delay between learning of the variant confirmation on Feb. 2 and when the tests had been conducted a week and a half earlier.

Hinshaw acknowledged it takes the lab system "some time" to retest positive cases for mutations. In one Calgary school case recently identified, she said the students had already completed their 14-day quarantine period and as such weren't being asked to quarantine again.

"The length of time from the original tests to the variants of concern, that is of course a challenge," she commented.

But, she countered, "The end of December was when we learned of the issue with respect to the increased transmissibility of the variant first identified in the U.K., the variant first identified in South Africa. And so if you think about the fact that the lab has – in just a handful of weeks – been able to ramp up their ability to screen for these very specific mutations is quite remarkable.

"A couple of weeks ago when this case was first identified as being a positive COVID case, we weren't yet at that point to be able to rapidly screen all of the tests. So at the moment we are improving our ability to move positive cases quickly through that screening protocol for variant mutations, and the timeframe therefore will be improved as we go forward."

Her department is looking at its options to use rapid testing in settings where there is greater risk of spread, though the top doctor has said it is not a replacement for PCR (polymerase chain reaction) testing.

The province also plans to mandate a second test for returning internal travellers 10 days after arrival. Earlier that week, Alberta changed isolation rules for multi-person households of incoming travellers.

517 HOSPITALIZATIONS, 93 IN ICU

That afternoon, Hinshaw reported 582 new cases: 421 positive results confirmed on Wednesday and some positive cases that had been found on Tuesday but not publicly reported. Those individuals had been notified of the positive result, Hinshaw said, and the government's website would be updated to reflect the mistake.

Alberta has a positivity rate of 3.6 per cent and 517 people in hospital, including 93 in ICUs.

Thirteen more Albertans have died from COVID-19.

Thirteen per cent, or 304 schools across the province, have active alerts or outbreaks and together account for 763 cases.

Alberta has seen more than 112,000 doses of COVID-19 vaccine administered, including more than 43,000 doses to some 21,700 Albertans who have been fully immunized.

Out of 112,000 doses, there have been 53 adverse events ranging from allergic reactions to rash and vomiting.

The benefit of receiving the vaccine still greatly outweighs the risk of experiencing an adverse event, Hinshaw told the public.

"Early investigations so far appear to suggest the current vaccines may be somewhat less effective against some of the new variants in terms of preventing all symptoms of COVID-19. However, even against the variants, these vaccines appear to be extremely effective at preventing severe cases, hospitalizations and deaths."