Ontario is poised to expand eligibility for a COVID-19 vaccine to those 40 years old and up, as well as those with a range of at-risk health conditions this week as it receives its largest shipments of vaccine supplies to date.

As of 8 a.m. on Tuesday, those with "at risk" health conditions will be able to book an appointment to get a vaccine. The at-risk group includes a wide range of conditions, such as dementia, diabetes, heart disease and sickle cell disease, as well as all respiratory illnesses such as asthma or bronchitis, and all types of cancer.

[Click here to see the full list of at-risk conditions

So far, the province has been offering vaccine appointments to those who have health conditions in the "high risk" and “highest risk” categories.

On Tuesday morning, an expanded list of people who cannot work from home will also become eligible, including grocery store, restaurant and transportation workers and others included in Group 2 in Ontario’s vaccine plan.

As of Thursday at 8 a.m., all those turning 40 and over in 2021 in the province will also become eligible to book through the provincial booking system. The change includes all residents of Toronto.

On Monday morning, York Region began offering vaccine appointments to all residents 40 and over. The region said it opened up approximately 78,000 appointments and that by 5 p.m., approximately 25,000 appointments had been booked at public health-led clinics.

The province also said Monday that it would start offering high-risk health care workers, dialysis patients, and all First Nations, Inuit and Métis individuals a second vaccine dose sometime this week due to the increase in supply.

The expanded eligibility across Ontario comes as the province begins to receive its largest vaccine shipments so far.

According to the federal government, Ontario is set to receive 787,410 doses of the Pfizer vaccine this week, along with 388,100 doses of the Moderna vaccine.

The province is scheduled to receive the same amount of Pfizer doses next week, along with 401,200 doses of Moderna.

While there is no delivery schedule for Moderna past next week, shipments of Pfizer to Ontario are expected to rise to around 930,000 doses per week starting in June.

While the federal government has promised that millions of AstraZeneca doses will arrive in the country by the end of June as well, there is currently no delivery schedule for the vaccine. Ontario's health minister suggested Monday that the province could start offering a second dose of a different vaccine to those who have received a first dose of AstraZeneca due to uncertain supply.

Last week, the province opened up appointments to all those 18 and over who live in one of the province’s 114 COVID-19 hotspots.

Over the weekend, the province also began offering Pfizer and Moderna doses to anyone 18 and over through pharmacies around the GTA.

There are now close to 80 pharmacies offering Pfizer in Toronto and Peel and as many as 60 pharmacies offering Moderna in Durham, Hamilton, Ottawa, Windsor-Essex and York Region. The province said Monday that more pharmacies will start offering the shots through May.