Ontario lowered its COVID-19 vaccine booster eligibility to all adults on Monday but it appears the majority of those searching for an appointment this morning were unable to book a shot online on the province’s central portal within the next month.

At about 7:50 a.m. on Monday, the province dropped the eligibility for a third shot of a COVID-19 vaccine to anyone 18 and up, provided it had been three months or longer since their second dose.

After waiting between 20 minutes to an hour or longer on the central COVID-19 vaccine appointment portal, most users in the province found few appointments scheduled any earlier than one month from now.

Approximately 15 minutes after the portal opened in Toronto, all but one of the listed mass vaccination sites on Monday morning offered any appointments before Jan. 20.

Toronto Mayor John Tory said the city was working to redeploy staff to boost the number of appointments available.

“We have opened up as many appointments as possible between now and Feb. 19 with more appointments to come. More than 84,000 appointments for adults in the city-run clinics were available this morning when eligibility opened up but we know that there is tremendous demand,” Tory said. “Over the coming days as we increase vaccination capacity further we will be announcing more appointments being made available.”

In Ottawa, the local public health unit said all booster dose appointments were filled within 14 minutes of the portal officially opening.

In York Region, the local public health unit said it was not yet opening up eligibility for people under 50, as it was focusing efforts on children and older individuals at higher risk of hospitalization.

In Simcoe-Muskoka, the local public health unit said it would limit all of its walk-in vaccine clinics to first and second doses, or third doses if the recipient was 50+ or part of a recognized priority group.

“We understand everyone is frustrated. As stated previously, due to overwhelming demand for booster doses, we are needing to prioritize our clinic capacity at this time,” the Simcoe-Muskoka District Health Unit wrote on Twitter.

Popular vaccine-finding volunteer group Vaccine Hunters Canada tweeted on Sunday night that several of its users aged 18 to 49 could book appointments for boosters already.

A spokesperson for Ontario Health Minister Christine Elliott said it is typical for portal to go live before its announced time.

"It is not uncommon for booking system eligibility to go live early when a new group becomes eligible for the COVID-19 vaccine," Alexandra Hilkene said. "This helps to ensure the booking system is ready to accept bookings and that caches are cleared for those accessing the booking system."

Dr. Andrew Boozary, director of social medicine for University Health Network, said Monday’s eligibility widening gave preferential treatment to the people who could sit on the portal longer than everyone else.

“There are only certain people who can afford to be online as much they have and to be able to get the spots in the deployments that have been made today,” he told CP24.

He said the lack of access to timely third doses or even diagnostic testing show him the province has not changed its approach to public health since the start of the pandemic.

“If you’re not able to have access to a booster, a third dose or a rapid antigen test, it’s a very different holiday season for some folks and these disparities have been the tale of two pandemics.”

Hilkene said Ontario residents should frequently check back at the portal in the coming days and weeks for newly available appointments.

“As we continue to increase our daily capacity, individual public health units are actively working to add appointments to the booking system on an ongoing basis,” Hilkene said Monday. “Public health units will continue to keep the public informed as more appointments go live on the provincial booking system. We also encourage Ontarians to check regularly for availability through other channels such as pharmacies, primary care settings, and walk-in clinics.”

She said about 186,000 people booked booster shot appointments on the central provincial portal between 8 a.m. and 3 p.m. Monday

Vaccine clinic staff and public health units told CTV News and CP24 that the province is experiencing a shortage of the Pfizer-BioNTech COVID-19 vaccine.

At some clinics, this meant the Pfizer jab was reserved for children and males below the age of 30, with everyone else receiving Moderna.

Hilkene said the province has requested four million additional doses of Pfizer for delivery between now and March, 2022.

“Given historical uptake of Pfizer vaccine, we have requested an additional four million Pfizer doses from the federal government in January, which have yet to be confirmed,” she told CTV News Toronto. “If the Pfizer inventory does run out, we will rely on Moderna until we receive additional supply of Pfizer from the federal government.”

NDP Leader Andrea Horwath tweeted about the eligibility expansion on Monday, calling it a “rough morning.”

“It’s been a rough morning for anyone looking for a rapid test or booster shot appointment. I’m going to keep fighting for more resources for public health units, and for Doug Ford to distribute millions more rapid tests.”