SARS-CoV-2 infection and smoking: What is the association? A brief review.

Susceptibility to severe illness from COVID-19 is anticipated to be associated with cigarette smoking as it aggravates the risk of cardiovascular and respiratory illness, including infections. This is particularly important with the advent of a new strain of coronaviruses, the severe acute respiratory syndrome coronavirus (SARS-CoV-2) that has led to the present pandemic, coronavirus disease 2019 (COVID-19). Although, the effects of smoking on COVID-19 are less described and controversial, we presume a link between smoking and COVID-19. Smoking has been shown to enhance the expression of the angiotensin-converting enzyme-2 (ACE-2) and transmembrane serine protease 2 (TMPRSS2) key entry genes utilized by SARS-CoV-2 to infect cells and induce a 'cytokine storm', which further increases the severity of COVID-19 clinical course. Nevertheless, the impact of smoking on ACE-2 and TMPRSS2 receptors expression remains paradoxical. Thus, further research is necessary to unravel the association between smoking and COVID-19 and to pursue the development of potential novel therapies that are able to constrain the morbidity and mortality provoked by this infectious disease. Herein we present a brief overview of the current knowledge on the correlation between smoking and the expression of SARS-CoV-2 key entry genes, clinical manifestations, and disease progression.

Gastrointestinal and Hepatic Involvement in Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Review.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has caused a pandemic coronavirus disease-19 (COVID-19) that began in Wuhan city, China, in December 2019. Till 14th April, 19,39,801 people have been affected by this virus, of whom 1,20,897 died. Though respiratory symptoms are the typical manifestation of this disease, gastrointestinal (GI) symptoms such as anorexia, nausea, vomiting, loss of taste sensation, diarrhea, abdominal pain, and discomfort have been reported. The pooled prevalence of GI symptom is 17.6% (95% confidence interval, 12.3%-24.5%), as indicated in a meta-analysis. A few studies suggested that the presence of GI symptoms is associated with poorer prognosis. The virus is excreted in feces during the acute disease, and even after, the nasopharyngeal swab has become negative for viral ribonucleic acid. Fecal viral excretion may have clinical significance because of possible feco-oral transmission of the infection. Nearly, 10.5%-53% of patients with COVID-19, particularly those with severe disease, have been shown to have an elevation of hepatic enzymes though biochemical and clinical jaundice are uncommon. Knowledge about this disease in general and GI involvement, in particular, is currently evolving.