EDMONTON -- It's not been a great few days, or weeks, for Edmonton's COVID-19 numbers. 

On Thursday, the city set new records for new daily cases (up 225) and increase in active cases (up by 132). Worryingly, both of those marks were well above the prior records that had themselves been set only two days before. 

Meanwhile, a new outbreak materialized at the Misericordia Community Hospital, the facility's second, forcing 29 people into isolation. And, by Friday, the city's active cases grew to 1,167, a record high number and one that represented more than half of all active cases in the province.

The rise in cases through September and into October prompted Alberta's chief medical officer of health, Dr. Deena Hinshaw to introduce new health measures, albeit voluntary ones, around gathering sizes, masks and cohorts.   

"I'm very concerned about the sharp rise in cases that we are seeing," Dr. Hinshaw told reporters Thursday. " I believe people will do their part to protect themselves and their family, friends and neighbours."

The city of Edmonton had a stronger message, warning further case growth could warrant renewed mandatory restrictions. 

"The increase in case numbers has persisted over many days and suggests people's attitudes and actions towards public health measures have become more relaxed," said interim city manager Adam Laughlin.

"City facility restrictions or even closures are a real consideration if Edmontonians don't respond in a positive way to this."

The rising case load and new voluntary restrictions, coupled with the Thanksgiving holiday weekend and colder weather forcing people indoors where the coronavirus spreads best, makes the upcoming three days a pivotal date in the city's battle against COVID-19. 

"Any measures you can take to limit epidemic increase very early really do change the eventual peak and size of the surge and so this is going to be a crucial weekend," said infectious disease specialist Dr. Lynora Saxinger. 

RAPID GROWTH

After spending much of the early weeks and months of the pandemic with relatively low case numbers, Edmonton's total and active cases ballooned in early August and then again in mid-September. 

Edmonton has had the most active cases of any Alberta municipality since Sept. 10.

The city's case count has grown rapidly since the summer to its current total of 5,681. 

It took 37 days for the city's cases to grow from 1,000 to 2,000. It took 20 days to grow from 2,000 to 3,000, 17 days to grow to 4,000 and just 11 days to grow from 4,000 to 5,000 cases. 

It's only Oct. 9, but already this month has seen the city's four highest daily case increases to date. 

The coronavirus has affected every area of the city, but the Northeast (150 actives), Northgate (146) and Castle Downs (123) subzones are the current hotspots, combining for 419 of the city's 1,167 active cases heading into the weekend. 

And while Alberta remains first in per capita testing of all provinces as it has for most of the pandemic, Edmonton has seen a general rise in test positivity percentage in recent weeks. 

On Thursday, the Edmonton Zone (which is bigger than the city itself) reported a 3.38 per cent positivity rate, the highest mark reported since April 5. That level fell to 2.35 per cent in Friday's report, still well above the province's test positivity rate of 1.21 per cent. 

The graph below shows a gradually increasing trend in the rate from around 1 per cent in summer before growing through August and into the early fall. 

SUBURBAN GROWTH

The recent rise in cases hasn't been restricted to the city itself as cases in neighbouring communities have also grown in recent weeks. 

St. Albert saw its active cases grow to a pandemic-high 33 in mid September and marked its second death earlier this week. 

Sherwood Park ended July with three active cases, but has grown again by 12 more cases on Friday, up to 55, third highest of any municipality in the province behind only Edmonton and Calgary.

Beaumont had zero active cases as recently as Sept. 22 but now has 17 after growing each of the past three days.

Leduc's active cases grew from five to 18 in the space of a week, prompting the city's mandatory mask bylaw to kick in.

Strathcona County, currently with 11 active cases heading into the weekend, also made masks mandatory in indoor public spaces amid climbing case counts.

LOW HOSPITALIZATIONS

There are, a few, bits of a potentially good news. 

Hospitalizations remain low across Alberta, and while rising this week in the Edmonton Zone, are still well within manageable limits, according to Dr. Hinshaw. 

However, the number of COVID-19 patients in hospital is a lagging indicator as infections recorded in past weeks worsen and require more acute care. Over time, more cases will result in more hospitalizations.

An outbreak at a care facility in the Mill Woods West subzone hasn't yet produced the sizable spike in deaths or active cases seen in a similar outbreak at the Good Samaritan Southgate Care Centre in the Duggan subzone.

And, after recording five deaths over last weekend, the city of Edmonton recorded one fatality the rest of the week.

Hospitalizations and deaths are key numbers as they show a definite toll of the pandemic on the province's population and health care system.

Last weekend saw the city set weekend records for most new cases (310) and largest increase in active cases (132), notable as those figures surpassed those set over three-day long weekends in September and August. 

While any infections transmitted over the Thanksgiving weekend won't be recorded for a few days to come, how this weekend's numbers trend will give the province an idea of if we can, once again, flatten the curve and avoid renewed public health measures.

"Whether or not additional restrictions may be needed again is entirely in our hands," said Dr. Hinshaw.

"Keep your Thanksgiving small. Keep it safe, and protect one another."