TORONTO - Ontario announced Wednesday that COVID-19 booster shots will be available to everyone next year, but starting Saturday the next priority group will be able to book appointments for six months past their second dose.

All of the following groups are being prioritized based on an increased risk of waning immunity six months after their second dose, as well as various other factors.

- People aged 70 and older have a high risk of severe illness from COVID-19.

- Health-care workers have a higher risk of exposure at work.

- First Nation, Inuit and Metis adults and their non-Indigenous household members are among communities disproportionately affected by COVID-19, as well as being faced with inequities related to the social determinants of health.

- People who received two doses of the AstraZeneca vaccine or the one-dose Janssen vaccine started with a lower vaccine efficacy than people who received an mRNA vaccine and may have a gradual waning immune response sooner.

- Further expansion of eligibility is expected to start in early 2022 based on the date of a second dose. Officials say the protection from two doses is still very high for the general population after six months, especially against severe illness and death, so a booster dose would provide additional protection against more mild illness.

This report by The Canadian Press was first published Nov. 3, 2021.