Ontario health officials are expressing concern that some available appointments for COVID-19 vaccines are going unbooked and that demand may not be matching current capacity.

An analysis of daily vaccinations shows that while the province set a target of 200,000 to 300,000 shots per day back in mid-December, that mark has only been reached on four days since then.

At a briefing Thursday, Ontario’s Chief Medical Officer of Health Dr. Kieran Moore urged people to book an appointment as soon as possible and said there was additional capacity.

“If there is an opportunity for you to rebook your vaccine appointment earlier than your current scheduled date, whether for your first or second dose or for your booster, please do not hesitate to do so. There are empty seats in some of our vaccination clinics,” Moore said.

Currently, anyone 18 and older is eligible to book a booster shot at least 84 days from their second COVID-19 vaccine dose. About 44.3 per cent of those 18+ have had a booster so far, with the strongest uptake among those 60 and over.

In an email Friday, Health Minister Christine Elliott’s office said demand is not as high as capacity at the moment.

“As Dr. Moore mentioned yesterday, the province has booster appointments available but current demand is not meeting Ontario’s capacity,” Elliott’s office said.

“Through more mass-vax sites, hospital clinics, employer-led clinics, pharmacies and primary care clinics, we have significantly scaled up our capacity to administer between 200,000 and 300,000 per day based on demand. The capacity is in place and appointments are available for Ontarians who want to get their vaccine sooner.”

Officials have urged people to get a booster shot as soon as possible as it offers stronger protection against the Omicron variant and boosters have been touted as one of the main weapons to fight the latest wave of infections.

Starting next week, automated calls will be going out to alert those who have booster appointments booked, that they may be able to reschedule to a sooner date.

The calls are set to begin next week in areas of the province with available capacity.

The move comes as some vaccination partners say that they are seeing many appointments going unbooked. One provider running clinics around the GTHA has only seen bookings for about a third of the appointments that they could manage.

Toronto Public Health told CP24.com Thursday that while city-run clinics are operating at maximum capacity, they are seeing some people cancel appointments after testing positive for COVID-19 or having to isolate because of symptoms or an exposure.

The city has also reported that it has seen people walk away from around two to three per cent of appointments because they would rather get a different brand of vaccine than the one being offered.

“Both Moderna and Pfizer are equally good and provide strong protection against COVID-19 and its variants, so please take the first vaccine available to you,” Moore said Thursday.

“In fact, Moderna is recommended for those who are older as it has robust and prolonged protection. It is as effective or in some studies more effective at protecting against hospitalization than the Pfizer vaccine. It is also safe and effective to receive what we call a mixed dosed series for a first, second and third dose of COVID-19 vaccines that are not the same vaccine brand.”

The province has also started administering fourth doses for those who are immunocompromised.