KITCHENER -- Waterloo Region's top doctor said that there are no plans to lower the pre-registration age for COVID-19 vaccines.

On Monday, Wellington-Dufferin-Guelph Public Health said anyone 16 and over can pre-register, but people in Phase Three of vaccination rollout likely won't get an appointment until June.

Councillors in Waterloo Region said they're now facing questions from residents who are asking if changes can be made to the priority groups currently eligible for vaccines.

Medical Officer of Health Dr. Hsiu-Li Wang said vaccine supply is based on 75 per cent capacity per capita and 25 per cent on the number of local hot spots. She said there are no current plans to lower the age for vaccine pre-registration or change the priority groups.

"If you're going to make a decision to slightly change prioritization and move a certain group up, you're going to inevitably move another group down," Dr. Wang told a Committee on the Whole meeting on Tuesday. "That isn't always evident. We just felt it makes more sense for us here locally to open up to groups that are next in line, so to speak, rather than all the groups. What WDG has done is open it up to everybody, it's the general population. We are not there yet."

Some regional councillors said they're also receiving complaints about the vaccine registration process, including people not receiving a follow-up message confirming pre-registration right away.

"I'm still seeing people that have pre-registered and they aren't getting anything from us," Kitchener Mayor Berry Vrbanovic said.

"We have well over 100,000 pre-registered and a 100,000 who have received pre-bookings," said Chief Administrative Officer Bruce Lauckner. "It's going to take up to four weeks before you get a call."

Public health officials said the web page will show a pop-up window confirming pre-registration, but people likely won't hear from public health directly for up to four weeks from pre-registering.

Dr. Kelly Grindrod, a vaccine expert from the University of Waterloo, said people are starting to get impatient.

"If you have been waiting for a long time for a vaccine, it can feel like there aren't a lot of people getting vaccinated, because you don't know anybody getting vaccinated, you haven't been offered a vaccine," she said. "People are having a really hard time seeing and imagining who is ahead of them."

To date, Waterloo Region has administered more than 116,000 vaccine doses, or just over 17 per cent of the population.

More than 15,000 people, or 2.6 per cent of the population, have received both doses and are considered fully vaccinated.