KITCHENER -- Waterloo Region's top doctor says the area has started to move into the third wave of COVID-19.

"We are beginning to see signs of a third wave in Waterloo Region," Medical Officer of Health Dr. Hsiu-Li Wang said at the region's COVID-19 briefing on Friday morning.

She said the weekly incidence rate rose again this week to 70 cases per 100,000 people. Last week, the rate was 50 cases per 100,000 people. The week prior, the rate was at 38 cases per 100,000 people.

Dr. Wang also said the reproductive rate rose above 1.0, now sitting at 1.2. The positivity rate in the region is at 4.6 per cent.

"Which shows cases are increasing," she said.

The number of variants of concern in the region also rose in the past week. As of Friday, 686 cases had screened positive for a variant in the region. Of those, 39 are confirmed as the B.1.1.7 variant first detected in the U.K.

"Variants of concern are the predominant strain in Ontario and we are now seeing that in Waterloo Region," Dr. Wang said.

Dr. Wang said she supports the stay-at-home order that came into effect across Ontario on Thursday at 12:01 a.m.

"The situation in Ontario is dire and we are all at-risk," she said.

According to Dr. Wang, the region's current rates are higher than they were when the second wave of the pandemic began in November.

"I expect cases in Waterloo Region to continue to climb in the next one to two weeks until the stay-at-home order can start to have an effect," she said. "Please stay at home except for essential purposes."

The stay-at-home order will help reduce opportunities for exposure to the disease.

"The higher the case counts, the harder it is to bring those case counts down," Dr. Wang said.

Regional officials will continue to monitor the situation in schools closely. Dr. Wang said parents and schools should prepare to moving to virtual learning after next week's April break, but said that decision wouldn't be made lightly.

"Schools should be the last to close and the first to open," she said.

The region's COVID-19 vaccine task force said they continue to ramp up distribution in the area.

Anyone who has been invited to book an appointment is asked to do so as soon as possible to help fill up capacity at local clinics.

Some pharmacies and primary care providers are now offering the AstraZeneca vaccine to people over the age of 55.

Adults aged 50 and over in priority neighbourhoods identified by the region can also now pre-register for the vaccine.

School staff working working with students with special education needs are also now eligible to receive their first vaccine dose.

Officials said people should continue following all public health measures after they receive the vaccine.