TORONTO -- A second case of blood clotting linked to the AstraZeneca COVID-19 vaccine has been confirmed in Ontario, health officials said. 

A man in his 60s from Hamilton is receiving care in hospital after he developed rare blood clotting, known as vaccine-induced immune thrombotic thrombocytopenia, following his first dose of the AstraZeneca vaccine, Hamilton Public Health said Friday evening. 

This case comes just hours after Chief Medical Officer of Health Dr. David Williams said another Ontario man in his 60s is recovering at home after suffering the same issue. 

In an interview with CTV News Toronto on Friday, the son of the Hamilton man who suffered the blood clotting said his father is currently in a critical condition at Hamilton General Hospital.

"He's been in hospital since April 18," his son, who did not want to be identified to protect the family's privacy, said. "The diagnosis was a severe stroke due to a blood clot in the brain." 

He said his father received the COVID-19 vaccine in early April and was fine until he started getting confused about two weeks later. 

He said his mother called 911 after he passed out getting a glass of water in the middle of the night. 

"At about 3 a.m. my mother heard a crash, my father had got up to get a glass a water and end up facedown unconscious on the living room floor," he said. 

He said his father's condition is "still touch-and-go" and he will require treatment in the intensive care unit for the "foreseeable future."

"Ultimately, my father is going to need care for the rest of his life if he ever comes out of hospital," he said. 

"It's one in a million that this would happen to our family."

Instances of blood clotting linked to the vaccine have been reported around the world and in other parts of Canada, but experts say the instances are rare.

"While these serious reactions remain extremely rare, there is a robust process in place to monitor for any adverse events and have taken steps to ensure that these events are identified and treated as quickly as possible," Hamilton's Medical Officer of Health Dr. Elizabeth Richardson said in a statement Friday.

Canada's National Advisory Committee on Immunization (NACI) had advised provinces to pause the use of the AstraZeneca-Oxford COVID-19 vaccine in people under the age of 55 because of the safety concerns. On Thursday, the committee revised its recommendation and said that the vaccine can now be offered to people 30 and over.

However, Health Canada has maintained that the benefits of the AstraZeneca vaccine outweigh the risks of getting COVID-19, and the agency approved the use of the vaccine for people 18 years old and over.

Premier Doug Ford, Health Minister Christine Elliott and Toronto Mayor John Tory all received their first dose of the AstraZeneca shots on camera recently in order to dispel concerns over the vaccine.

Prime Minister Justin Trudeau and his wife, Sophie Gregoire Trudeau, received their first doses of the vaccine in the afternoon on Friday.

Earlier this week, the Ontario government began offering the vaccine to people 40 years old and over in pharmacies and primary care settings.

Williams reiterated in his statement on Friday that all COVID-19 vaccines administered in Canada are safe and prevent serious illness, hospitalization and death related to the deadly disease.