SP-A protein levels are increased in the serum, plasma and sputum of smokers (Kida et al., 1997; Nomori et al., 1998; Mazur et al., 2011), providing another rationale for the proposed beneficial effects of smoking or nicotine consumption in preventing COVID-19 (Farsalinos et al., 2020a). The gene discussed is SFTPA2; the disease is COVID-19.