Electronic cigarette use and risk of COVID-19 among young adults without a history of cigarette smoking

It is unknown whether use of e-cigarettes increases susceptibility to COVID-19. In a large clinical sample of young adults, we evaluated whether current or ever e-cigarette use was associated with polymerase chain reaction (PCR)-confirmed COVID-19. To address the confounding of combustible smoking, the sample was restricted to never smokers. This retrospective cohort study analyzed data from the electronic health records of 74,853 young adults (aged 18–35 years), without a history of cigarette smoking, who were screened for e-cigarette use (current, former, never) in the Kaiser Permanente Northern California (KPNC) healthcare system from 3/5/2020 (baseline) to 11/30/2020 (pre-vaccine). COVID-19 risk was estimated in time-to-event analyses using multivariable Cox proportional hazard regression models, adjusted for socio-demographics and medical comorbidities. E-cigarette status in the cohort was: 1.6% current, 1.2% former, and 97.2% never. During follow-up, 1965 (2.6%) patients acquired COVID-19. We did not find evidence that current (vs never) e-cigarette use was associated with risk of COVID-19 (aHR = 1.12 95%CI:0.77–1.62). However, we did find suggestive evidence that former (versus never) e-cigarette use may be associated with greater risk of COVID-19 (aHR = 1.39 95%CI:0.98–1.96). While e-cigarette use is associated with health risks for young adults, results from this study suggest that current use of e-cigarettes may not increase susceptibility for COVID-19 among young adults who have never smoked cigarettes.