SARS CoV-2-Induced Viral Sepsis: The Role of Gut Barrier Dysfunction.

A considerable proportion of patients with severe COVID-19 meet Sepsis-3 criteria and share common pathophysiological mechanisms of multiorgan injury with bacterial sepsis, in absence of secondary bacterial infections, a process characterized as "viral sepsis". The intestinal barrier exerts a central role in the pathophysiological sequence of events that lead from SARS-CoV-2 infection to severe systemic complications. Accumulating evidence suggests that SARS-CoV-2 disrupts the integrity of the biological, mechanical and immunological gut barrier. Specifically, microbiota diversity and beneficial bacteria population are reduced, concurrently with overgrowth of pathogenic bacteria (dysbiosis). Enterocytes' tight junctions (TJs) are disrupted, and the apoptotic death of intestinal epithelial cells is increased leading to increased gut permeability. In addition, mucosal CD4(+) and CD8(+) T cells, Th17 cells, neutrophils, dendritic cells and macrophages are activated, and T-regulatory cells are decreased, thus promoting an overactivated immune response, which further injures the intestinal epithelium. This dysfunctional gut barrier in SARS-CoV-2 infection permits the escape of luminal bacteria, fungi and endotoxin to normally sterile extraintestinal sites and the systemic circulation. Pre-existing gut barrier dysfunction and endotoxemia in patients with comorbidities including cardiovascular disease, obesity, diabetes and immunosuppression predisposes to aggravated endotoxemia. Bacterial and endotoxin translocation promote the systemic inflammation and immune activation, which characterize the SARS-CoV-2 induced "viral sepsis" syndrome associated with multisystemic complications of severe COVID-19.

Gut and airway microbiota and their role in COVID-19 infection and pathogenesis: a scoping review.

BACKGROUND: The SARS-CoV-2 virus is responsible for the COVID-19 pandemic. Researchers have been studying the pathogenesis of the virus with the aim to improve our current diagnosis and management strategies. The microbiota have been proposed to play a key role in the pathogenesis of the disease. PURPOSE: To investigate and report on the current available evidence on any associations between the gut and/or airway microbiota and the pathogenesis of COVID-19. METHODS: Using a predefined protocol in compliance with the PRISMA guidelines, a search was conducted on MEDLINE, Science Direct, DOAJ and Cochrane databases on primary research studies assessing the association between COVID-19 infection and the gut and/or airway microbiota. RESULTS: Twenty-two studies were included in the current review; nineteen studies concluded an association between the gut and/or airway dysbiosis and SARS-CoV-2, while 3 studies failed to observe a significant association between the airway microbiome and SARS-CoV-2 infection. Specifically, most studies reported a decrease in microbial diversity and therefore development of intestinal dysbiosis in COVID-19-positive patients compared to healthy controls as well as a possible association between increased intestinal dysbiosis and disease severity. CONCLUSION: During infection with SARS-CoV-2, there are significant changes in the composition of the gut and airway microbiota. Furthermore, the gut microbiota may have a more important role than the airway microbiota in COVID-19 infection. In the future, studies should be more carefully designed to derive more conclusive evidence on the role of the gut and airway microbiota following infection with SARS-CoV-2 which will lead to the formulation of better management strategies in combating COVID-19.

Extensive Testing and Public Health Interventions for the Control of COVID-19 in the Republic of Cyprus between March and May 2020.

Coronavirus disease 2019 (COVID-19) has significantly affected the well-being of individuals worldwide. We herein describe the epidemiology of COVID-19 in the Republic of Cyprus during the first epidemic wave (9 March-3 May 2020). We analyzed surveillance data from laboratory-confirmed cases, including targeted testing and population screening. Statistical analyses included logistic regression. During the surveillance period, 64,136 tests (7322.3 per 100,000) were performed, 873 COVID-19 cases were diagnosed, and 20 deaths were reported (2.3%). Health-care workers (HCWs) represented 21.4% of cases. Overall, 19.1% of cases received hospital care and 3.7% required admission to Intensive Care Units. Male sex (adjusted Odds Ratio (aOR): 3.04; 95% Confidence Interval (CI): 1.97-4.69), increasing age (aOR: 1.56; 95%CI: 1.36-1.79), symptoms at diagnosis (aOR: 6.05; 95%CI: 3.18-11.50), and underlying health conditions (aOR: 2.08; 95%CI: 1.31-3.31) were associated with hospitalization. For recovered cases, the median time from first to last second negative test was 21 days. Overall, 119 primary cases reported 616 close contacts, yielding a pooled secondary attack rate of 12% (95%CI: 9.6-14.8%). Three population-based screening projects, and two projects targeting employees and HCWs, involving 25,496 people, revealed 60 positive individuals (0.2%). Early implementation of interventions with targeted and expanded testing facilitated prompt outbreak control on the island.