MONTREAL - Health Canada has reported a second case in Quebec of serious lung illness linked to vaping.

The two Quebec cases are the only confirmed ones so far, but three more in the rest of Canada are considered likely to be linked to vaping: two in New Brunswick and one in British Columbia.

In mid-September, a similar case was reported in London, Ont., but has since been reclassified as being under investigation; public-health officials say the announced diagnosis in that instance was premature.

Health Canada is reminding the public that vaping has risks and the long-term effects of vaping remain unknown.

The exact cause of lung illnesses linked to vaping remains unclear and is still being studied in both Canada and the United States.

Health Canada notes that vaping products may contain dozens of chemicals and that most vapes are flavoured and contain nicotine.

The federal agency also warns people against using illegally obtained vaping products, including ones that include cannabis, as they are not subject to any controls or surveillance by health or law enforcement authorities.

This report by The Canadian Press was first published Oct. 24, 2019.