Corona Virus Disease 2019 (COVID-19) is a disease caused by a novel coronavirus, SARS-CoV-2. On 23 March, we presented for the first time evidence of a low prevalence of smoking among hospitalized patients with COVID-19 in China. On 3 April, we were the first to establish the hypothesis that nicotine may be beneficial for COVID-19 patients and should be evaluated in clinical trials due to its anti-inflammatory properties. We present briefly the hypothesis that COVID-19 could be a disease of the nicotinic cholinergic system. Additionally we emphasize that researchers should be cautious when presenting previously-published (or pre-published) work as their own "novel" work. Copying methodologies and reporting previously-presented hypotheses without citing the original authors, especially when publication and pre-publication dates are documented, can be considered plagiarism and a breach of intellectual property copyright.

The study purpose was to examine the prevalence of current e-cigarette use and current smoking among hospitalized patients with COVID-19 in China, considering the high population smoking prevalence in the country (26.6%, 50.5% in males and 2.1% in females). A systematic research of the literature (PubMed) was performed on April 1. Out of 432 studies, we identified 13 studies examining the clinical characteristics of a total of 5960 hospitalized COVID-19 patients that presented data on the smoking status. No study reported e-cigarette use among COVID-19 patients. The prevalence of current smoking ranged from 1.4% to 12.6%. The random effect pooled prevalence of current smoking was 6.5% (95%CI: 4.9-8.2%).This preliminary analysis does not support the argument that current smoking is a risk factor for hospitalization for COVID-19. Instead, these consistent observations, which are further emphasized by the low prevalence of current smoking among COVID-19 patients in the US (1.3%), raises the hypothesis that nicotine may have beneficial effects on COVID-19. This could be attributed to its immunomodulatory effects and its interaction with the renin-angiotensin system. However, other confounding factors need to be considered and the accuracy of the recorded smoking status needs to be determined. However, the results were remarkably consistent across all studies and were recently verified in the first case series of COVID-19 cases in the US. In conclusion, the generalized advice to quit smoking as a measure to improve health risk remains valid, but no recommendation can currently be made concerning the effects of smoking on the risk of hospitalization for COVID-19. No studies recording e-cigarette use status among hospitalized COVID-19 patients were identified. Thus, no recommendation can be made for e-cigarette users. The above-mentioned observations, together with the potential mechanisms through which nicotine interacts with the inflammatory process and the renin-angiotensin-aldosterone axis involved in the development of COVID-19, warrant an urgent investigation of the clinical effects of pharmaceutical nicotine on COVID-19 susceptibility, progression and severity.