TORONTO - Immunocompromised Ontarians can book appointments for a fourth dose of a COVID-19 vaccine starting this morning.

Ontario's chief medical officer of health, Dr. Kieran Moore, says appointments for moderately to severely immunocompromised people will be made available through the provincial vaccine contact centre at 8 a.m.

Moore said the move aims to provide further protection for vulnerable populations.

The province has already started administering fourth doses in long-term care homes, retirement homes and other congregate settings.

In a news conference Thursday, Ontario's top doctor also said transplant patients are lagging in getting their third doses of a COVID-19 vaccine, which is considered part of their primary series of shots.

He said only 64 per cent of transplant patients have received a third dose so far.

This report by The Canadian Press was first published Jan. 14, 2022.