Introduction: The aim of this study was to explore demographic and clinical characteristics of vaping-associated lung illness (VALI) cases reported in Canada from September 2019 to December 2020; compare the epidemiology of VALI cases in Canada to e-cigarette or vaping product use-associated lung injury (EVALI) cases in the US; and examine possible explanations for differences between the two countries.

Methods: A federal/provincial/territorial task group developed a national outbreak definition, minimum dataset and case report form for identification and surveillance of VALI cases in Canada. Descriptive analysis explored the characteristics and epidemiology of reported VALI cases.

Results: Of the 20 VALI cases reported, none resulted in a death. Of all cases, 5 (25%) involved youth aged 15 to 19 years, 10 (50%) adults aged 20 to 49 years and 5 (25%) aged 50 years and older. Sixty percent of patients were men. Half (50%) required breathing assistance. Three-quarters (75%) reported using nicotine-containing vaping products, and 40% reported use of cannabis-containing vaping products; of those who reported frequency of vaping, most (71%) reported vaping daily. VALI cases were reported at a lower prevalence (0.9 per million) than EVALI (8.5 per million). Demographics and vaping behaviour also differed.

Conclusion: VALI cases were reported in Canada between September 2019 and December 2020; however, there was a much lower prevalence and they may have been caused by different factors from the EVALI outbreak in the US. The factors influencing VALI in Canada are complex and multifactorial. Research is needed to understand the short- and long-term health effects of nicotine and cannabis vaping.