Current Smoking is Not Associated with COVID-19

We have read with interest the paper by Leung et al. recently published in European Respiratory Journal [1], reporting a higher expression of the protein ACE-2 in the small airways epithelia of smokers and COPD patients with putatively important implications for COVID-19 patients since ACE-2 has been shown to be the receptor utilised by SARS-CoV-2 to enter the host cells [2]. Furthermore the Authors reported that current smokers showed a higher expression of ACE-2 gene expression than non-smokers, concluding that the increased ACE-2 expression in smokers might predispose to increased risk of SARS-CoV-2 infection [1].
Despite the main complications of SARS-CoV-2 infection regard lung involvement, the prevalence of current smoking in COVID-19 patients is very low even if one might have anticipated that opposite. Thus, the epidemiological data seem to question the role of coexisting active smoking as a risk factor for COVID-19 pneumonia.