Understanding the long-term maintenance of SARS-CoV-2 immunity is critical for predicting protection against reinfection. In an age and gender matched cohort of 24 participants, the association of disease severity and early immune responses on the maintenance of humoral immunity 12 months post-infection is examined. All severely affected participants maintain a stable subset of SARS-CoV-2 receptor-binding domain (RBD)-specific memory B cells (MBCs) and good neutralising antibody breadth against the majority of the variants of concern, including the Delta variant. Modelling these immune responses against vaccine efficacy data indicate 45-76% protection against symptomatic infection (variant dependent). Overall, these findings indicate durable humoral responses in most participants after infection, reasonable protection against reinfection, and implicate baseline antigen-specific CD4+ T cell responses as a predictor of maintenance of antibody neutralisation breadth and RBD-specific MBC levels at 12 months post-infection.

Protection against pathogens using personal protective equipment is essential yet challenging in healthcare settings. Concerns over emerging biothreats and outbreaks of infectious diseases underscore the need for antimicrobial and biocompatible protective clothing to protect patients and staff. Herein, we report the antimicrobial efficacy and cytotoxicity of cotton/silk fabrics containing embedded reduced graphene oxide (RGO) and Ag/Cu nanoparticles (NPs), prepared using a 3-glycidyloxypropyl trimethoxy silane coupling agent followed by chemical reduction and vacuum heat treatment. Embedding NPs on top of the RGO layer substantially increased the antimicrobial activity. All RGO–Ag NPs or RGO–Cu NPs embedded in cotton or silk fabrics reduced the viability of approximately 99% of the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. RGO–Ag NPs embedded into cotton or silk fabrics reduced the viability of the Gram-positive bacterium Staphylococcus aureus by 78–99%, which was higher than the growth inhibition by RGO–Cu NPs samples against S. aureus. Both silk and cotton containing RGO–Cu NPs produced a greater reduction in the viability of the yeast Candida albicans compared to RGO–Ag NPs fabrics. All RGO–Ag NPs or RGO–Cu NPs embedded in cotton or silk fabrics showed good washing durability by sustaining good bactericidal activity, even on washing up to 10 times. Moreover, none of the RGO–Ag or RGO–Cu fabrics reduced mammalian cells’ (HEK293) viability by >30%, suggesting low cytotoxicity and good biocompatibility. These findings show that RGO–NPs embedded in cotton or silk fabrics have great potential for use in protective clothing and medical textiles.

BackgroundInfection with the hepatitis E virus (HEV) can cause acute hepatitis in endemic areas in immune-competent hosts, as well as chronic infection in immune-compromised subjects in non-endemic areas. Most studies assessing HEV infection in HIV-infected populations have been performed in developed countries that are usually affected by HEV genotype 3. The objective of this study is to measure the prevalence and risk of acquiring HEV among HIV-infected individuals in Nepal.MethodsWe prospectively evaluated 459 Human Immunodeficiency Virus (HIV)-positive individuals from Nepal, an endemic country for HEV, for seroprevalence of HEV and assessed risk factors associated with HEV infection. All individuals were on antiretroviral therapy and healthy blood donors were used as controls.ResultsWe found a high prevalence of HEV IgG (39.4%) and HEV IgM (15.3%) in HIV-positive subjects when compared to healthy HIV-negative controls: 9.5% and 4.4%, respectively (OR: 6.17, 95% CI 4.42–8.61, p < 0.001 and OR: 3.7, 95% CI 2.35–5.92, p < 0.001, respectively). Individuals residing in the Kathmandu area showed a significantly higher HEV IgG seroprevalance compared to individuals residing outside of Kathmandu (76.8% vs 11.1%, OR: 30.33, 95% CI 18.02–51.04, p = 0.001). Mean CD4 counts, HIV viral load and presence of hepatitis B surface antigen correlated with higher HEV IgM rate, while presence of hepatitis C antibody correlated with higher rate of HEV IgG in serum. Overall, individuals with HEV IgM positivity had higher levels of alanine aminotransferase (ALT) than IgM negative subjects, suggesting active acute infection. However, no specific symptoms for hepatitis were identified.ConclusionsHIV-positive subjects living in Kathmandu are at higher risk of acquiring HEV infection as compared to the general population and to HIV-positive subjects living outside Kathmandu.

HBV and HCV infections are widespread among the HIV-infected individuals in Nepal. The goals of this study were to investigate the epidemiological profile and risk factors for acquiring HBV and/or HCV coinfection in disadvantaged HIV-positive population groups in Nepal. We conducted a retrospective study on blood samples from HIV-positive patients from the National Public Health Laboratory at Kathmandu to assay for HBsAg, HBeAg, and anti-HCV antibodies, HIV viral load, and CD4+ T cell count. Among 579 subjects, the prevalence of HIV-HBV, HIV-HCV, and HIV-HBV-HCV coinfections was 3.62%, 2.93%, and 0.34%, respectively. Multivariate regression analysis indicated that spouses of HIV-positive migrant labourers were at significant risk for coinfection with HBV infection, and an age of >40 years in HIV-infected individuals was identified as a significant risk factor for HCV coinfection. Overall our study indicates that disadvantaged population groups such as intravenous drug users, migrant workers and their spouses, female sex workers, and men who have sex with HIV-infected men are at a high and persistent risk of acquiring viral hepatitis. We conclude that Nepalese HIV patients should receive HBV and HCV diagnostic screening on a regular basis.