The clinical progress and challenges of mRNA vaccines.

Owing to the breakthroughs in the prevention and control of the COVID-19 pandemic, messenger RNA (mRNA)-based vaccines have emerged as promising alternatives to conventional vaccine approaches for infectious disease prevention and anticancer treatments. Advantages of mRNA vaccines include flexibility in designing and manipulating antigens of interest, scalability in rapid response to new variants, ability to induce both humoral and cell-mediated immune responses, and ease of industrialization. This review article presents the latest advances and innovations in mRNA-based vaccines and their clinical translations in the prevention and treatment of infectious diseases or cancers. We also highlight various nanoparticle delivery platforms that contribute to their success in clinical translation. Current challenges related to mRNA immunogenicity, stability, and in vivo delivery and the strategies for addressing them are also discussed. Finally, we provide our perspectives on future considerations and opportunities for applying mRNA vaccines to fight against major infectious diseases and cancers. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Biology-Inspired Nanomaterials > Lipid-Based Structures.

Delayed generation of functional virus-specific circulating T follicular helper cells correlates with severe COVID-19.

Effective humoral immune responses require well-orchestrated B and T follicular helper (Tfh) cell interactions. Whether these interactions are impaired and associated with COVID-19 disease severity is unclear. Here, longitudinal blood samples across COVID-19 disease severity are analysed. We find that during acute infection SARS-CoV-2-specific circulating Tfh (cTfh) cells expand with disease severity. SARS-CoV-2-specific cTfh cell frequencies correlate with plasmablast frequencies and SARS-CoV-2 antibody titers, avidity and neutralization. Furthermore, cTfh cells but not other memory CD4 T cells, from severe patients better induce plasmablast differentiation and antibody production compared to cTfh cells from mild patients. However, virus-specific cTfh cell development is delayed in patients that display or later develop severe disease compared to those with mild disease, which correlates with delayed induction of high-avidity neutralizing antibodies. Our study suggests that impaired generation of functional virus-specific cTfh cells delays high-quality antibody production at an early stage, potentially enabling progression to severe disease.

Risk assessment of port congestion risk during the COVID-19 pandemic

With the COVID-19 outbreak hitting the world, the frequency and severity of port congestion caused by various factors are increasing, challenging the stability of international supply chains. Thus, it is necessary to conduct an in-depth study on congestion risks to reduce their adverse impacts on congestion. Although traditional criticality analysis techniques may be capable of ranking port congestion risk in common scenarios, new risk analysis methods are urgently required to tackle uncertainty along with the COVID-19 pandemic. This paper develops a methodology designed for the identification and prioritization of port congestion risk during the pandemic. First, a novel congestion risk assessment model is established by extending the risk prioritization index (RPI) suggested by failure mode and effects analysis (FMEA). Next, the combination of fuzzy Bayesian reasoning, AHP and the variation coefficient method is incorporated into the model in a complementary way to facilitate the treatment of uncertainty and quantitative analysis of the congestion under the different influence of risk factors in ports. Finally, the mode introduces a set of risk utility values for calculating the RPI for prioritization. A real case study and a sensitivity analysis were carried out to illustrate and validate the proposed model. The results proved that the applied method is feasible and functional. In the illustrative example, the top three risk factors are "Interruption of railways/barges services", "Skilled labor shortage" and "Shortage of truck-drivers/drayage truck". The findings obtained from this paper could provide useful insights for risk prevention and mitigation.

B-Cell Receptor Features and Database Establishment in Recovered COVID-19 Patients by Combining 5'-RACE with PacBio Sequencing.

BACKGROUND: Antibodies induced by viral infection can not only prevent subsequent virus infection, but can also mediate pathological injury following infection. Therefore, understanding the B-cell receptor (BCR) repertoire of either specific neutralizing or pathological antibodies from patients convalescing from Coronavirus disease 2019 (COVID-19) infection is of benefit for the preparation of therapeutic or preventive antibodies, and may provide insight into the mechanisms of COVID-19 pathological injury. METHODS: In this study, we used a molecular approach of combining 5' Rapid Amplification of cDNA Ends (5'-RACE) with PacBio sequencing to analyze the BCR repertoire of all 5 IgH and 2 IgL genes in B-cells harvested from 35 convalescent patients after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. RESULTS: We observed numerous BCR clonotypes within most COVID-19 patients, but not in healthy controls, which validates the association of the disease with a prototypical immune response. In addition, many clonotypes were found to be frequently shared between different patients or different classes of antibodies. CONCLUSIONS: These convergent clonotypes provide a resource to identify potential therapeutic/prophylactic antibodies, or identify antibodies associated with pathological effects following infection with SARS-CoV-2.

Human influenza virus infection elicits distinct patterns of monocyte and dendritic cell mobilization in blood and the nasopharynx.

During respiratory viral infections, the precise roles of monocytes and dendritic cells (DCs) in the nasopharynx in limiting infection and influencing disease severity are incompletely described. We studied circulating and nasopharyngeal monocytes and DCs in healthy controls (HCs) and in patients with mild to moderate infections (primarily influenza A virus [IAV]). As compared to HCs, patients with acute IAV infection displayed reduced DC but increased intermediate monocytes frequencies in blood, and an accumulation of most monocyte and DC subsets in the nasopharynx. IAV patients had more mature monocytes and DCs in the nasopharynx, and higher levels of TNFα, IL-6, and IFNα in plasma and the nasopharynx than HCs. In blood, monocytes were the most frequent cellular source of TNFα during IAV infection and remained responsive to additional stimulation with TLR7/8L. Immune responses in older patients skewed towards increased monocyte frequencies rather than DCs, suggesting a contributory role for monocytes in disease severity. In patients with other respiratory virus infections, we observed changes in monocyte and DC frequencies in the nasopharynx distinct from IAV patients, while differences in blood were more similar across infection groups. Using SomaScan, a high-throughput aptamer-based assay to study proteomic changes between patients and HCs, we found differential expression of innate immunity-related proteins in plasma and nasopharyngeal secretions of IAV and SARS-CoV-2 patients. Together, our findings demonstrate tissue-specific and pathogen-specific patterns of monocyte and DC function during human respiratory viral infections and highlight the importance of comparative investigations in blood and the nasopharynx.

Real-world effectiveness of Azvudine in hospitalized patients with COVID-19: a retrospective cohort study (preprint)

Current guidelines prioritize the use of the Azvudine in coronavirus disease 2019 (COVID-19) patients. However, the clinical effectiveness of Azvudine in real-world studies was lacking, despite the clinical trials showed shorter time of nucleic acid negative conversion. To evaluate the clinical effectiveness following Azvudine treatment in hospitalized COVID-19 patients, we identified 1505 hospitalized COVID-19 patients during the study period, with a follow-up of up to 29 days. After exclusions and propensity score matching, we included 226 Azvudine recipients and 226 matched controls. The lower crude incidence rate of composite disease progression outcome (4.21 vs. 10.39 per 1000 person-days, P=0.041) and all-cause mortality (1.57 vs. 6.00 per 1000 person-days, P=0.027) were observed among Azvudine recipients compared with matched controls. The incidence rates of initiation of invasive mechanical ventilation were also statistically different between the groups according to the log-rank tests (P=0.020). Azvudine treatment was associated with significantly lower risks of composite disease progression outcome (hazard ratio [HR]: 0.43; 95% confidence interval [CI]: 0.18 to 0.99) and all-cause death (HR: 0.26; 95% CI: 0.07 to 0.94) compared with matched controls. Subgroup analyses indicated robustness of the point estimates of HRs (ranged from 0.14 to 0.84). Notably, male Azvudine recipients had a stronger effectiveness than female recipients with respect to both composite outcome and all-cause death. These findings suggest that Azvudine treatment showed substantial clinical benefits in hospitalized COVID-19 patients, and should be considered for use in this population of patients.

Real-world effectiveness of Azvudine in hospitalized patients with COVID-19: a retrospective cohort study (preprint)

Current guidelines prioritize the use of the Azvudine in coronavirus disease 2019 (COVID-19) patients. However, the clinical effectiveness of Azvudine in real-world studies was lacking, despite the clinical trials showed shorter time of nucleic acid negative conversion. To evaluate the clinical effectiveness following Azvudine treatment in hospitalized COVID-19 patients, we identified 1505 hospitalized COVID-19 patients during the study period, with a follow-up of up to 29 days. After exclusions and propensity score matching, we included 226 Azvudine recipients and 226 matched controls. The lower crude incidence rate of composite disease progression outcome (4.21 vs. 10.39 per 1000 person-days, P=0.041) and all-cause mortality (1.57 vs. 6.00 per 1000 person-days, P=0.027) were observed among Azvudine recipients compared with matched controls. The incidence rates of initiation of invasive mechanical ventilation were also statistically different between the groups according to the log-rank tests (P=0.020). Azvudine treatment was associated with significantly lower risks of composite disease progression outcome (hazard ratio [HR]: 0.43; 95% confidence interval [CI]: 0.18 to 0.99) and all-cause death (HR: 0.26; 95% CI: 0.07 to 0.94) compared with matched controls. Subgroup analyses indicated robustness of the point estimates of HRs (ranged from 0.14 to 0.84). Notably, male Azvudine recipients had a stronger effectiveness than female recipients with respect to both composite outcome and all-cause death. These findings suggest that Azvudine treatment showed substantial clinical benefits in hospitalized COVID-19 patients, and should be considered for use in this population of patients.

Serological response following COVID-19 vaccines in patients living with HIV: a dose-response meta- analysis (preprint)

Conclusions: We concluded that vaccine doses were associated with consistently improved the rate and risk ratio of seroconversion in patients living with HIV, highlighting the significance of booster vaccination for patients living with HIV. Objective: To quantify the pooled rate and risk ratio of seroconversion following the uncomplete, complete, or booster dose of COVID-19 vaccines in patients living with HIV. Method: Pubmed, Embase and Cochrane library were searched for eligible studies published from inception to 13th, September 2022. The pooled rate and risk ratio of seroconversion were assessed using the Freeman-Tukey double arcsine method and Mantel-Haenszel approach, respectively. Random-effects model was preferentially used as the primary approach to pool results across studies. This systematic review and meta-analysis protocol was registered with PROSPERO (CRD42022359603). Results: In this meta-analysis, we comprehensively analyzed 50 studies with a total of 7160 patients living with HIV. We demonstrated that only 75.0% (56.4% to 89.9%) patients living with HIV achieved a seroconversion after uncomplete vaccination, which improved to 89.3% (84.2% to 93.5%) after complete vaccination, and 98.4% (94.8% to 100%) after booster vaccination. The seroconversion rates were significantly lower compared to controls at all the stages, while the risk ratios for uncomplete, complete, and booster vaccination were 0.87 (0.77 to 0.99), 0.95 (0.92 to 0.98), and 0.97 (0.94 to 0.99), respectively. Notably, meta-regression and subgroup analyses suggested that year of publication, study location and vaccine type could cause the difference of the pooled rate or risk ratio of seroconversion for patients living with HIV after complete vaccination. Sensitivity analysis did not much change the results. Conclusions: We concluded that vaccine doses were associated with consistently improved the rate and risk ratio of seroconversion in patients living with HIV, highlighting the significance of booster vaccination for patients living with HIV.

Systematic identification of chemical components in Fufang Shuanghua oral liquid and screening of potential active components against SARS-CoV-2 protease.

Coronavirus disease (COVID-19) caused by SARS-COV-2 infection has been widely prevalent in many countries and has become a common challenge facing mankind. Traditional Chinese medicine (TCM) has played a prominent role in this pandemic, and especially TCM with the function of "heat-clearing and detoxifying" has shown an excellent role in anti-virus. Fufang Shuanghua oral liquid (FFSH) has been used to treat the corresponding symptoms of influenza such as fever, nasal congestion, runny nose, sore throat, and upper respiratory tract infections in clinic, which are typical symptoms of COVID-19. The content of chlorogenic acid, andrographolide and dehydrated andrographolide as the quality control components of FFSH is not less than 1.0 mg/mL, 60 µg/mL and 60 µg/mL respectively. In this study, UPLC-Q-TOF-MS/MS was employed to describe the chemical profile of FFSH. Virtual screening and fluorescence resonance energy transfer (FRET) were used to screen the effective components of FFSH acting on SARS-CoV-2 main protease (Mpro). As a result, 214 compounds in FFSH were identified or preliminarily characterized by UPLC-Q-TOF-MS/MS, and 61 active ingredients with potential inhibitory effects on Mpro were selected through receptor-based and ligand-based virtual screening. In particular, quercetin, forsythoside A, and linoleic acid showed a good inhibitory effect on Mpro in FRET evaluation with IC50 values of 26.15 µM, 22.26 µM and 47.09 µM respectively, and had a strong binding affinity with the receptor Mpro (6LU7) in molecular docking. CYS145 and HIS41 were the main amino acid residues affected by small molecules in the protein binding domain. In brief, we characterized, for the first time, 214 chemical components in FFSH, and three of them, including quercetin, forsythoside A and linoleic acid, were screened out to exert beneficial anti-COVID-19 effects through CYS145 and HIS41 sites, which may provide a new research strategy for TCM to develop new therapeutic drugs against COVID-19.

Analysis of the Carbon Intensity of Container Shipping on Trunk Routes: Referring to the Decarbonization Trajectory of the Poseidon Principle

Container shipping industries are highly capital intensive. If shipping carriers want to execute international shipping financing, they must follow the IMO emission reduction targets and meet the decarbonization trajectory of the Poseidon Principle (PP). This article used an activity-based model to calculate container shipping industry carbon emissions. It was found that the carbon intensity per unit for each ship was decreased because of the upsizing of container vessels and route deployment based on the alliance strategy. On the Asia–Europe (A/E) trunk route, as the ship size increased from 11,300 to 24,000 TEU, the results showed that the carbon intensity ranged from 6.48 to 3.06 g/ton-nm. It is also proven that the mega-container deployment on the A/E trunk route followed the decarbonization trajectory proposed by PP, while the Asia–Pacific trunk route was not fully in line with the trajectory of EEOI/AER. It is worth noting that starting from 2020, due to the COVID-19 pandemic, shipping companies deployed a higher number of small-size vessels to boost revenues, resulting in more pollutants produced and a mismatch of the trajectory proposed by PP.

Hotel guest satisfaction during COVID-19 outbreak: The moderating role of crisis response strategy.

Taking appropriate strategies in response to the COVID-19 crisis has presented significant challenges to the hospitality industry. Based on situational crisis communication theory (SCCT), this study aims to examine how the hotel industry has adopted strategies in shaping customers' experience and satisfaction. A mixed-method approach was employed by analysing 6556 COVID-19 related online reviews. The qualitative findings suggest that 'rebuild strategies' dominated most hotels' response to the COVID-19 crisis while the quantitative findings confirm the direct impact of affective evaluation and cognitive effort on customer satisfaction. The results further reveal that hotels' crisis response strategies moderate the effects of affective evaluation and cognitive effort on customer satisfaction. The study contributes to new knowledge on health-related crisis management and expands the application of SCCT in tourism research.

Young Adults’ Loneliness and Depression During the COVID-19 Pandemic: A Moderated Mediation Model

Since the outbreak of the COVID-19 pandemic in December 2019, millions of people have been infected with the disease. The COVID-19 pandemic also produced severe mental health problems, such as loneliness and depression. The present study aimed to examine the mediating role of cognitive reappraisal and moderating role of resilience in the relationship between young adults’ loneliness and depression during the pandemic by adopting a cross-sectional research approach. In March 2020, 654 young adults (18–29 years old) were recruited to complete the measures for loneliness, depression, emotion regulation, and resilience. Results found that loneliness was positively and moderately associated with depression (r = 0.531, p < 0.001), and that both loneliness and depression were separately negatively associated with cognitive reappraisal (r = −0.348, p < 0.001;r = −0.424, p < 0.001) and resilience (r = −0.436, p < 0.001;r = −0.419, p < 0.001). The results indicated that both loneliness and depression were not associated with expressive suppression (r = 0.067, p = 0.087;r = −0.002, p = 0.961). The moderated mediation model results revealed that only cognitive reappraisal partially mediated the relationship between loneliness and depression (b = −0.301;Boot 95% CI = −0.388, −0.215). In addition, the results of the moderated mediation model indicated that resilience moderated the association between loneliness and depression (b = 0.035, p < 0.001, Boot 95% CI = 0.014, 0.055), while also moderated the impact of cognitive reappraisal on depression (b = −0.031, p < 0.001, Boot 95% CI = −0.058, −0.005). These findings have practical implications that broaden our understanding of depression in young adults and shed light on how to enhance cognitive reappraisal and resilience as a means of combating depression in this age group during the COVID-19 pandemic.

Folic acid: a potential inhibitor against SARS-CoV-2 nucleocapsid protein.

CONTEXT: Coronavirus disease 2019 is a global pandemic. Studies suggest that folic acid has antiviral effects. Molecular docking shown that folic acid can act on SARS-CoV-2 Nucleocapsid Phosphoprotein (SARS-CoV-2 N). OBJECTIVE: To identify novel molecular therapeutic targets for SARS-CoV-2. MATERIALS AND METHODS: Traditional Chinese medicine targets and virus-related genes were identified with network pharmacology and big data analysis. Folic acid was singled out by molecular docking, and its potential target SARS-CoV-2 N was identified. Inhibition of SARS-CoV-2 N of folic acid was verified at the cellular level. RESULTS: In total, 8355 drug targets were potentially involved in the inhibition of SARS-CoV-2. 113 hub genes were screened by further association analysis between targets and virus-related genes. The hub genes related compounds were analysed and folic acid was screened as a potential new drug. Moreover, molecular docking showed folic acid could target on SARS-CoV-2 N which inhibits host RNA interference (RNAi). Therefore, this study was based on RNAi to verify whether folic acid antagonises SARS-CoV-2 N. Cell-based experiments shown that RNAi decreased mCherry expression by 81.7% (p < 0.001). This effect was decreased by 8.0% in the presence of SARS-CoV-2 N, indicating that SARS-CoV-2 N inhibits RNAi. With increasing of folic acid concentration, mCherry expression decreased, indicating that folic acid antagonises the regulatory effect of SARS-CoV-2 N on host RNAi. DISCUSSION AND CONCLUSIONS: Folic acid may be an antagonist of SARS-CoV-2 N, but its effect on viruses unclear. In future, the mechanisms of action of folic acid against SARS-CoV-2 N should be studied.

Chemical constituents and biological activities of Artemisia argyi H.Lév. & vaniot.

Artemisia argyi is a widely distributed and inexpensive plant resource, and study on its chemical compositions and biological activities will provide an important basis for its food applications and pharmaceutical developments. In this study, fourteen known guaiane-type sesquiterpenes (1-14), four known eudesmane-type sesquiterpenes (15-18), two known germacranolide-type sesquiterpenes (19, 20), and eight other types of terpenoids (20-28) were isolated from the leaves of A. argyi by polyamide and ODS CC and HPLC. The structures of all compounds are determined by 1 D NMR (1H-NMR、13C-NMR) and literature comparison. Among them, compounds 1 and 8 were isolated from Chinese folk medicine A. argyi for the first time. Besides, the LPS-induced RAW264.7 cell model has been evaluated the anti-inflammatory activities in vitro by the Griess reagent. The results indicated that the guaianolide sesquiterpenoids obtained from A. argyi have an excellent ability to inhibit NO production, especially Argyin A, a guaianolide sesquiterpenoid with isovaleryloxy substitution.

Defense of COVID-19 by Human Organoids.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has created an immense menace to public health worldwide, exerting huge effects on global economic and political conditions. Understanding the biology and pathogenesis mechanisms of this novel virus, in large parts, relies on optimal physiological models that allow replication and propagation of SARS-CoV-2. Human organoids, derived from stem cells, are three-dimensional cell cultures that recapitulate the cellular organization, transcriptional and epigenetic signatures of their counterpart organs. Recent studies have indicated their great values as experimental virology platforms, making human organoid an ideal tool for investigating host-pathogen interactions. Here, we summarize research developments for SARS-CoV-2 infection of various human organoids involved in multiple systems, including lung, liver, brain, intestine, kidney and blood vessel organoids. These studies help us reveal the pathogenesis mechanism of COVID-19, and facilitate the development of effective vaccines and drugs as well as other therapeutic regimes.

An Overview of System Strength Challenges in Australia’s National Electricity Market Grid

The national electricity market (NEM) of Australia is reforming via the rapid uptake of variable renewable energy (VRE) integration concurrent with the retirement of conventional synchronous generation. System strength has emerged as a prominent challenge and constraint to power system stability and ongoing grid connection of VRE such as solar and wind. In order to facilitate decarbonization pathways, Australia is the first country to evolve system strength and inertia frameworks and assessment methods to accommodate energy transition barriers, and other parts of the world are now beginning to follow the same approach. With the evolvement of the system strength framework as a new trending strategy to break the transition barriers raised by renewable energy project development and grid connection studies, this paper provides a high-level overview of system strength, covering such fundamental principles as its definition, attributes, and manifestations, as well as industry commentary, cutting-edge technologies and works currently underway for the delivery of a secure and reliable electricity system with the rapid integration of inverter-based resources (IBRs) in the NEM grid. The intent of this study is to provide a comprehensive reference on the engineering practices of the system strength challenge along with complementary technical, regulatory, and industry perspectives.

Analysis of TCR Repertoire by High-Throughput Sequencing Indicates the Feature of T Cell Immune Response after SARS-CoV-2 Infection.

Coronavirus disease 2019 (COVID-19) is a global infectious disease caused by the SARS-CoV-2 coronavirus. T cells play an essential role in the body's fighting against the virus invasion, and the T cell receptor (TCR) is crucial in T cell-mediated virus recognition and clearance. However, little has been known about the features of T cell response in convalescent COVID-19 patients. In this study, using 5'RACE technology and PacBio sequencing, we analyzed the TCR repertoire of COVID-19 patients after recovery for 2 weeks and 6 months compared with the healthy donors. The TCR clustering and CDR3 annotation were exploited to discover groups of patient-specific TCR clonotypes with potential SARS-CoV-2 antigen specificities. We first identified CD4+ and CD8+ T cell clones with certain clonal expansion after infection, and then observed the preferential recombination usage of V(D) J gene segments in CD4+ and CD8+ T cells of COVID-19 patients with different convalescent stages. More important, the TRBV6-5-TRBD2-TRBJ2-7 combination with high frequency was shared between CD4+ T and CD8+ T cells of different COVID-19 patients. Finally, we found the dominant characteristic motifs of the CDR3 sequence between recovered COVID-19 and healthy control. Our study provides novel insights on TCR in COVID-19 with different convalescent phases, contributing to our understanding of the immune response induced by SARS-CoV-2.

Airway antibodies emerge according to COVID-19 severity and wane rapidly but reappear after SARS-CoV-2 vaccination.

Understanding the presence and durability of antibodies against SARS-CoV-2 in the airways is required to provide insights into the ability of individuals to neutralize the virus locally and prevent viral spread. Here, we longitudinally assessed both systemic and airway immune responses upon SARS-CoV-2 infection in a clinically well-characterized cohort of 147 infected individuals representing the full spectrum of COVID-19 severity, from asymptomatic infection to fatal disease. In addition, we evaluated how SARS-CoV-2 vaccination influenced the antibody responses in a subset of these individuals during convalescence as compared with naive individuals. Not only systemic but also airway antibody responses correlated with the degree of COVID-19 disease severity. However, although systemic IgG levels were durable for up to 8 months, airway IgG and IgA declined significantly within 3 months. After vaccination, there was an increase in both systemic and airway antibodies, in particular IgG, often exceeding the levels found during acute disease. In contrast, naive individuals showed low airway antibodies after vaccination. In the former COVID-19 patients, airway antibody levels were significantly elevated after the boost vaccination, highlighting the importance of prime and boost vaccinations for previously infected individuals to obtain optimal mucosal protection.

Natural biflavones are potent inhibitors against SARS-CoV-2 papain-like protease.

Papain-like protease (PLpro) is a key enzyme encoded by SARS-CoV-2 that is essential for viral replication and immune evasion. Significant suppression of viral spread and promotion of antiviral immunity can be achieved by inhibition of PLpro, revealing an inspiring strategy for COVID-19 treatment. This study aimed to discover PLpro inhibitors by investigating the national compound library of traditional Chinese medicines (NCLTCMs), a phytochemical library comprising over 9000 TCM-derived compounds. Through virtual screening and enzymatic evaluations, nine natural biflavones were confirmed to be effective PLpro inhibitors with IC50 values ranging from 9.5 to 43.2 µM. Pro-ISG15 cleavage assays further demonstrated that several biflavones exhibited potent inhibitory effects against PLpro-mediated deISGylation, a key process involved in viral immune evasion. Herein, we report the discovery, antiviral evaluation, structure-activity relationship elucidation and molecular docking investigation of biflavones as potent inhibitors of SARS-CoV-2 PLpro.