KITCHENER -- Waterloo Region's top doctor says close contact continues to be the driving force behind the local spread of COVID-19.

"At this time, our case rates aren't continuing to accelerate, but our situation remains extremely fragile," Medical Officer of Health Dr. Hsiu-Li Wang said at a Committee on the Whole meeting on Tuesday morning.

According to Dr. Wang, spread of the disease is mostly due to close contacts. Since April 1, she said close contact transmission has accounted for more cases of COVID-19 than all other transmission types combined.

"In the presence of others outside of your immediate household, please remember three things," Dr. Wang said. "One, keep your distance. Two, wear a face covering. Three, only hold gatherings outdoors."

She said the Delta variant, which was first identified in India, continues to circulate widely in the region and is mostly targeting people who haven't received a COVID-19 vaccine at all, or those who have only had one dose. Dr. Wang added that's similar to what health units are seeing across Ontario.

"What's happening here could happen anywhere," Dr. Wang said.

Last week, Dr. Wang said the Delta variant is the dominant strain in Waterloo Region. Local officials are working to accelerate both first and second doses of COVID-19 vaccines for local residents.

"Vaccines are our most powerful tool and are very effective against severe illness and hospitalization," Dr. Wang said. "We're the canary in the coal mine in terms of what can happen when Delta takes off and spreads through the community."

The spike in cases locally is due to usual risk factors, along with the more transmissible Delta variant, Dr. Wang said. She added it's similar to the spread of the Alpha variant, first identified in the U.K., throughout the GTA during the third wave of the COVID-19 in Ontario.

"Delta has gotten a foothold, spreading quickly and widely," she said. "It's looking for any vulnerability and there is still vulnerability in our region because there are still a proportion of people are unimmunized."

Dr. Wang also reminded people to get the first vaccine available to them, adding it is safe to mix Pfizer and Moderna between first and second doses.

"Both are highly and equally effective," she said. "They're like twins."

EXPANDING VACCINE AVAILABILITY WITH INCREASED SUPPLY

Regional officials plan to ramp up both first and second doses as vaccine supply increases.

Starting Wednesday, walk-in appointments will be available at The Boardwalk, Health Sciences and Waterloo Region Public Health for first doses. Dr. Wang said they're working the Ministry of Health to offer mobile vaccine clinics as soon as possible.

"We have gotten out the vaccine as quickly as we've gotten it in," she said.

They're also working with community partners to target high-priority areas, and working on campaigns to encourage vaccination uptake in all age groups.

CHANGES TO BOOKING SYSTEM

Waterloo Region will launch a new vaccine booking system on Wednesday, which will allow people to forego the pre-registration process and book their appointment directly.

The new system will also allow people to reschedule an earlier second dose appointment. Starting Wednesday, anyone who received an mRNA vaccine on or before May 30 is eligible for an accelerated second dose.

Anyone who previously filled out a second dose request form will be invited to book a new appointment on Tuesday before the region transitions to its new booking system.

The system will also cancel appointments once a new one is confirmed.

Officials warned the new system might be very busy on Wednesday as more people become eligible for a second dose.