INTRODUCTION: Omicron is the latest SARS-CoV-2 variant of concern, the pathogen that causes COVID-19. Since its emergence in late 2021, Omicron has displaced other circulating variants and caused successive waves of infection worldwide throughout 2022. Omicron is characterised by the rapid emergence of many subvariants and high rates of infection in people with vaccine- and/or infection induced immunity. This review article will consolidate current knowledge regarding Omicron subvariants, the role of boosters, and future vaccine development. METHOD: This narrative review is based on a literature search using PubMed. Search terms related to Omicron were used and priority was given to published peer-reviewed articles over pre-prints. RESULTS: Studies indicate that vaccinations and boosters are important to reduce disease severity, hospitalisation, and death from Omicron. A variety of factors, such as differing host factors, circulating variants, and forces of infection, can influence the benefit of repeated booster administration. Next-generation bivalent vaccines have now been approved in some countries including Singapore and have demonstrated the ability to induce broad variant protection. Future third-generation vaccines involving mucosal vaccines and/or pan-sarbecovirus vaccines may provide broader and longer-lasting protection. CONCLUSION Due to current high levels of vaccine- and infection-induced immunity, it is likely that rates of severe illness, hospitalisation, and death due to Omicron will continue to moderate. Nevertheless, the virus is ever-changing, and public health policies, especially those related to vaccinations, will also have to continually evolve and adapt as COVID-19 transitions to endemicity.
Humans ; SARS-CoV-2 ; COVID-19/prevention & control* ; Vaccines ; Hospitalization

Antimalarials ; therapeutic use ; Disease Eradication ; economics ; Humans ; Malaria ; diagnosis ; drug therapy ; prevention & control

Betacoronavirus ; Coronavirus Infections ; epidemiology ; transmission ; Disease Transmission, Infectious ; statistics & numerical data ; Global Health ; Humans ; Incidence ; Pandemics ; Pneumonia, Viral ; epidemiology ; transmission ; Prognosis

This study investigated the regulatory role of nerve growth factor (NGF) in sirtuin 1 (SIRT1) expression in cholestatic livers. We evaluated the expression of NGF and its cognate receptors in human livers with hepatolithiasis and the effects of NGF therapy on liver injury and hepatic SIRT1 expression in a bile duct ligation (BDL) mouse model. Histopathological and molecular analyses showed that the hepatocytes of human diseased livers expressed NGF, proNGF (a precursor of NGF), TrkA and p75NTR, whereas only p75NTR was upregulated in hepatolithiasis, compared with non-hepatolithiasis livers. In the BDL model without NGF therapy, p75NTR, but not TrkA antagonism, significantly deteriorated BDL-induced liver injury. By contrast, the hepatoprotective effect of NGF was abrogated only by TrkA and not by p75NTR antagonism in animals receiving NGF therapy. Intriguingly, a positive correlation between hepatic SIRT1 and NGF expression was found in human livers. In vitro studies demonstrated that NGF upregulated SIRT1 expression in mouse livers and human Huh-7 and rodent hepatocytes. Both NGF and proNGF induced protective effects against hydrogen peroxide-induced cytotoxicity in Huh-7 cells, whereas inhibition of TrkA and p75NTR activity prevented oxidative cell death. Mechanistically, NGF, but not proNGF, upregulated SIRT1 expression in human Huh-7 and rodent hepatocytes via nuclear factor (NF)-κB activity, whereas NGF-induced phosphoinositide-3 kinase/Akt, extracellular signal–regulated kinase and NF-κB signaling and SIRT1 activity were involved in its hepatoprotective effects against oxidative injury. These findings suggest that pharmacological manipulation of the NGF/SIRT1 axis might serve as a novel approach for the treatment of cholestatic disease.
Animals ; Bile Ducts ; Cell Death ; Cholestasis ; Hepatocytes ; Humans ; Hydrogen ; In Vitro Techniques ; Ligation ; Liver ; Mice ; Nerve Growth Factor ; Phosphotransferases ; Rodentia ; Sirtuin 1

Objective: Problematic use of social media (PUSM) may affect sleep quality and self-stigma in people with schizophrenia and consequently reduce their quality of life (QoL). This longitudinal study investigated if sleep quality and self-stigma mediated relationships between PUSM and QoL. Methods: One-hundred-and-ninety-three outpatients with schizophrenia were recruited from a psychiatric center in Taiwan from April 2019 to August 2021 and participated in a longitudinal study at intervals of three months between measurements. QoL was assessed using the World Health Organization Quality of Life Questionnaire Brief Version; sleep quality using the Pittsburgh Sleep Quality Index; self-stigma using the Self-Stigma Scale-Short; and PUSM using the Bergen Social Media Addiction Scale. Via SPSS 20.0, general estimating equation models assessed temporal associations between variables. Via R software, mediating effects of self-stigma and sleep quality were examined through Monte Carlo simulations with 20,000 repetitions. Results: Mean scores of physical, psychological, social and environmental QoL ranged from 11.86 to 13.02. Mean scores of sleep quality and self-stigma were 9.1±4.5 and 2.2±0.8, respectively. Sleep quality and self-stigma were directly related to QoL (p<0.001) and mediated indirect relationships between PUSM and all components of QoL with a range of 95% confidence intervals spanning from -0.0591 to -0.0107 for physical QoL; -0.0564 to -0.0095 for psychological QoL; -0.0292 to -0.0035 for social QoL; and -0.0357 to -0.0052 for environmental QoL. Conclusion Sleep quality and self-stigma mediated relationships between PUSM and QoL in people with schizophrenia. Developing interventions targeting PUSM, sleep, and self-stigma may help improve QoL in people with schizophrenia.

Background/Aims: Obstacles exist in facilitating hepatitis C virus (HCV) care cascade. To increase timely and accurate diagnosis, disease awareness and accessibility, in-hospital HCV reflex testing followed by automatic appointments and a late call-back strategy (R.N.A. model) was applied. We aimed to compare the HCV treatment rate of patients treated with this strategy compared to those without. Methods: One hundred and twenty-five anti-HCV seropositive patients who adopted the R.N.A. model in 2020 and another 1,396 controls treated in 2019 were enrolled to compare the gaps in accurate HCV RNA diagnosis to final treatment allocation. Results: The HCV RNA testing rate was significantly higher in patients who received reflex testing than in those without reflex testing (100% vs. 84.8%, P<0.001). When patients were stratified according to the referring outpatient department, a significant improvement in the HCV RNA testing rate was particularly noted in patients from non-hepatology departments (100% vs. 23.3%, P<0.001). The treatment rate in HCV RNA seropositive patients was 83% (83/100) after the adoption of the R.N.A. model, among whom 96.1% and 73.9% of patients were from the hepatology and non-hepatology departments, respectively. Compared to subjects without R.N.A. model application, a significant improvement in the treatment rate was observed for patients from non-hepatology departments (73.9% vs. 27.8%, P=0.001). The application of the R.N.A. model significantly increased the in-hospital HCV treatment uptake from 6.4% to 73.9% for patients from non-hepatology departments (P<0.001). Conclusions The care cascade increased the treatment uptake and set up a model for enhancing in-hospital HCV elimination.

BACKGROUND: This study investigated whether xenotransplantation of human Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) reduces thioacetamide (TAA)-induced mouse liver fibrosis and the underlying molecular mechanism. METHODS: Recipient NOD/SCID mice were injected intraperitoneally with TAA twice weekly for 6 weeks before initial administration of WJ-MSCs. Expression of regenerative and pro-fibrogenic markers in mouse fibrotic livers were monitored post cytotherapy. A hepatic stallate cell line HSC-T6 and isolated WJ-MSCs were used for in vitro adhesion, migration and mechanistic studies. RESULTS: WJ-MSCs were isolated from human umbilical cords by an explant method and characterized by flow cytometry. A single infusion of WJ-MSCs to TAA-treated mice significantly reduced collagen deposition and ameliorated liver fibrosis after 2-week therapy. In addition to enhanced expression of hepatic regenerative factor, hepatocyte growth factor, and PCNA proliferative marker, WJ-MSC therapy significantly blunted pro-fibrogenic signals, including Smad2, RhoA, ERK. Intriguingly, reduction of plasma fibronectin (pFN) in fibrotic livers was noted in MSC-treated mice. In vitro studies further demonstrated that suspending MSCs triggered pFN degradation, soluble pFN conversely retarded adhesion of suspending MSCs onto type I collagen-coated surface, whereas pFN coating enhanced WJ-MSC migration across mimicked wound bed. Moreover, pretreatment with soluble pFN and conditioned medium from MSCs with pFN strikingly attenuated the response of HSC-T6 cells to TGF-b1-stimulation in Smad2 phosphorylation and RhoA upregulation. CONCLUSION These findings suggest that cytotherapy using WJ-MSCs may modulate hepatic pFN deposition for a better regenerative niche in the fibrotic livers and may constitute a useful anti-fibrogenic intervention in chronic liver diseases.

BACKGROUND: This study investigated whether xenotransplantation of human Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) reduces thioacetamide (TAA)-induced mouse liver fibrosis and the underlying molecular mechanism. METHODS: Recipient NOD/SCID mice were injected intraperitoneally with TAA twice weekly for 6 weeks before initial administration of WJ-MSCs. Expression of regenerative and pro-fibrogenic markers in mouse fibrotic livers were monitored post cytotherapy. A hepatic stallate cell line HSC-T6 and isolated WJ-MSCs were used for in vitro adhesion, migration and mechanistic studies. RESULTS: WJ-MSCs were isolated from human umbilical cords by an explant method and characterized by flow cytometry. A single infusion of WJ-MSCs to TAA-treated mice significantly reduced collagen deposition and ameliorated liver fibrosis after 2-week therapy. In addition to enhanced expression of hepatic regenerative factor, hepatocyte growth factor, and PCNA proliferative marker, WJ-MSC therapy significantly blunted pro-fibrogenic signals, including Smad2, RhoA, ERK. Intriguingly, reduction of plasma fibronectin (pFN) in fibrotic livers was noted in MSC-treated mice. In vitro studies further demonstrated that suspending MSCs triggered pFN degradation, soluble pFN conversely retarded adhesion of suspending MSCs onto type I collagen-coated surface, whereas pFN coating enhanced WJ-MSC migration across mimicked wound bed. Moreover, pretreatment with soluble pFN and conditioned medium from MSCs with pFN strikingly attenuated the response of HSC-T6 cells to TGF-b1-stimulation in Smad2 phosphorylation and RhoA upregulation. CONCLUSION These findings suggest that cytotherapy using WJ-MSCs may modulate hepatic pFN deposition for a better regenerative niche in the fibrotic livers and may constitute a useful anti-fibrogenic intervention in chronic liver diseases.

The complete picture regarding transmission modes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. This review summarises the available evidence on its transmission modes, our preliminary research findings and implications for infection control policy, and outlines future research directions. Environmental contamination has been reported in hospital settings occupied by infected patients, and is higher in the first week of illness. Transmission via environmental surfaces or fomites is likely, but decontamination protocols are effective in minimising this risk. The extent of airborne transmission is also unclear. While several studies have detected SARS-CoV-2 ribonucleic acid in air samples, none has isolated viable virus in culture. Transmission likely lies on a spectrum between droplet and airborne transmission, depending on the patient, disease and environmental factors. Singapore's current personal protective equipment and isolation protocols are sufficient to manage this risk.
COVID-19 ; Hospitals ; Humans ; Infection Control/methods* ; Personal Protective Equipment ; SARS-CoV-2