and PharmaCielo. Lecture fees from a number of European EC industry and trade associations (including FIVAPE in France and FIESEL in Italy) were directly donated to vaper advocacy no-profit organizations. RP is also founder of: 1) the Center for Tobacco prevention and treatment (CPCT) at the University of Catania; and 2) the Center of Excellence for the acceleration of Harm Reduction (CoEHAR) at the same University, which has received support from Foundation for a Smoke Free World to conduct 8

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... ndependent investigator-initiated research projects on harm reduction. He is currently scientific advisor for LIAF, Lega Italiana Anti Fumo (Italian acronym for Italian Anti-Smoking League) and Head of the European Technical Committee for standardization on "Requirements and test methods for emissions of electronic cigarettes" (CEN/TC 437; WG4). Abstract We discuss the plausibility, scope and risk for SARS-CoV-2 virus transmission through respiratory droplets potentially carried by e-cigarette aerosol (ECA) exhaled by infected vapers. Considering observational data on droplet emission rates of mouth breathing as a proxy model for this transmission, droplet diameters should be overwhelmingly in the submicron range. For the most common low intensity puffing style (practiced by 80-90% of vapers) we estimate emission rates of 2-230 droplets per puff horizontally transported 0.5-2 meters in the direction of the exhaled jet. Considering that vaping is an intermittent respiratory expiration associated with a short duration exposure and assuming contagion risks to be proportional to the SARS-CoV-2 viral load of emitted droplets, we estimate that vaping represents about 1% added risk with respect to the ever existing risk from continuous rest breathing in indoor spaces with natural ventilation (as a reference, speaking for 6 minutes per hour increases this risk to 44%). The added risks remain negligible with universal wearing of face masks protecting bystanders. Direct aerial transmission of the SARS-CoV-2 virus borne by respiratory droplets is a fact already acknowledged by the WHO [1] and the CDC [2]. Indirect transmission by smaller droplets (often referred to as 'aerosols') is also proven [3], but its reach and frequency remain controversial [4, 5] . The current COVID19 pandemic has intensified the existing scientific Qeios, CC-BY 4.0 · Article,