Second-hand smoke surveillance and COVID-19: a missed opportunity.

SARS-CoV-2 infection (COVID-19) causes severe respiratory illness and multiorgan inflammatory disease.1 Smoking, cardiovascular disease (CVD), hypertension and chronic lung diseases are risk factors for COVID-19 severity.2–4 Second-hand tobacco smoke (SHS) exposure is a known causal risk factor for CVD and chronic lung disease,5 and may also be a risk factor for COVID-19 severity, either through its role in these underlying conditions, or through its inflammatory effect on upregulation of ACE-2 receptors, mediating COVID-19 cell entry.4 However, a lack of SHS surveillance makes it difficult to quantify any potential relationship or to make evidence-informed recommendations about the effects of SHS exposure on COVID-19 incidence or severity. To learn more about whether SHS exposure was being assessed in COVID-19 studies, we contacted researchers who had published COVID-19-related work. We contacted corresponding authors of peer-reviewed scientific articles published between February and April of 2020 identified by PubMed systematic searches using ‘COVID OR Coronavirus AND Risk Factors’ and similar terms. Abstracts were reviewed and papers included if they had data from patients with COVID-19 and risk factors. We …