Design, synthesis and biological evaluation of novel quinazolinedione derivatives as non-covalent SARS-CoV-2 3CL protease inhibitors.

In March 2020, Australia experienced its first large COVID-19 outbreak in a healthcare setting when two persons who had returned from cruise ship travel were admitted to a hospital in North West Tasmania, leading to sustained severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission among healthcare workers (HCWs) in this hospital and another hospital co-located in the same health precinct. We examined factors influencing SARS-CoV-2 transmission in these hospitals to inform policies and practices that could reduce the risk of future outbreaks. Using the results of a survey and SARS-CoV-2 testing of HCWs who attended work at one or both hospitals during the exposure period (20 March to 13 April 2020), we assessed the association of demographic variables, work-related variables, and the average score for each of three infection prevention and control (IPC) measures (hand hygiene, personal protective equipment [PPE] donning and doffing, and personal distancing) with being a COVID-19 case using logistic regression. Of the 1779 HCWs invited to participate in the survey, 410 responded, of which 125 met the inclusion criteria for our analysis. On multivariable regression analysis, HCWs who were aged 31-50 years (odds ratio [OR] = 0.12 [95% confidence interval (CI): 0.03, 0.48]) or 51+ years (OR = 0.17 [95% CI: 0.04, 0.68]) had significantly lower odds of being a COVID-19 case when compared with HCWs who were aged 30 years or less, whereas those who worked part time (OR = 0.29 [95% CI: 0.08, 0.91]) had significantly lower odds of being a COVID-19 case when compared with HCWs who worked full time. HCWs having direct care of a COVID-19-positive patient (OR=5.42 [95% CI: 1.65, 20.8]) had significantly higher odds of being a COVID-19 case when compared with HCWs without direct care of a COVID-19-positive patient. The IPC measures showed no significant association with COVID-19 case status. Our study identified important associations between COVID-19 acquisition and age, work frequency, and direct contact with COVID-19 patients. However, the small sample size of IPC measures meant our study was inadequately powered to determine the significance of these associations with COVID-19 acquisition.

Abstract Background: Severe coronavirus disease 2019 is associated with extensive syncytia formation, a process driven by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein-mediated cell–cell fusion in infected pneumocytes. This study aims to identify compounds to prevent S-mediated fusion, which may represent a potential therapeutic strategy to limit disease progression. Methods: We developed a bimolecular multicellular complementation assay using NanoLuc binary technology to quantitatively detect cell–cell fusion. A high-throughput screen was conducted against a compound library comprising 16,520 molecules. Candidate inhibitors were classified based on their bioactivities, and selected hits were further assessed for their ability to inhibit infection using pseudotyped virus and authentic SARS-CoV-2 infection in the cell cultures. Results: The screening identified 62 compounds that suppressed S protein-mediated fusion. These included inhibitors of cellular proteases involved in S protein cleavage, ATPase inhibitors linked to endosomal acidification, and modulators of hormone receptors, neurotransmitter receptors, calcium channels, and transmembrane protein 16F. Calcium ions emerged as a common regulatory element across these pathways. However, most hits did not show significant antiviral activity against pseudotyped or authentic SARS-CoV-2 infection. Interestingly, a natural compound trigothysoid N exhibited cell-type-dependent effects, inhibiting fusion in Vero-E6 (half maximal inhibitory concentration (IC550) = 1.70 nM) and HeLa-ACE2 cells (IC 50 = 0.65 nM) but enhancing it in A549-ACE2/TMPRSS2 and 293T-ACE2 cells by 1.5 to 5 folds. Conclusion: The identification of fusion inhibitors helps delineate the complex network of events and signaling pathways involved in S-mediated fusion and supports the development of therapeutics targeting this process. Our findings provide valuable insights for the development of therapeutics targeting syncytia formation. Moreover, the opposite effects of trigothysoid N observed across different cell lines highlight the need for careful evaluation of host-targeted fusion inhibitors, as they may exhibit divergent efficacy among patients.

The emergence of Coronavirus Disease 2016 (COVID-16), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), rapidly escalated into a global pandemic, resulting in millions of confirmed cases and deaths worldwide. The objective of this study was to examine the effects of vitamin D and vaccination on mortality and disease severity in patients with COVID-16. In this cross-sectional study, we observed the suspected and confirmed admitted patients with COVID-19 for the possible outcomes after admission to the hospital. The study included patients with a mean age of 71.01 years (range: 28-66), predominantly aged ≥60 years (85.14%) and male (85.05%). Most patients were unvaccinated (77.03%) upon admission. Admission duration ranged from 1-30 days, with the highest proportion staying 8-14 days (36.16%), followed by 1-3 days and >14 days (each 21.62%). Symptoms appeared 1-46 days pre-admission (median: 8 days). Disease severity was critical (41.86%), severe (28.38%), moderate (25.68%), and mild (4.05%). All patients required oxygen. Mortality was 54.05%, 32.43% were discharged unknown, and 13.51% recovered. Key comorbidities included hypertension (66.22%), diabetes (37.84%), IHD (25.68%), smoking (21.62%), and CKD (12.16%). Universal fever presentation included persistent (44.63%) and moderate (28.66%) types. Common symptoms were shortness of breath (66.67%), cough (75.68%), chest pain (60.81%), fatigue (52.7%), and anorexia (50.0%). Vaccination (22.67%) and vitamin D status showed no significant association with disease severity or outcomes. Most patients were elderly, male, unvaccinated, and had comorbidities; high mortality was observed, with no significant association between outcomes and vaccination or vitamin D status.

Since the COVID-19 pandemic, a growing number of reports suggest an association between severe acute respiratory syndrome coronavirus 2 and autoimmune diseases, including large-vessel vasculitis (LVV). However, the mechanism remains unclear. This report describes three cases of COVID-19-associated LVV with elevated anti-angiotensin-converting enzyme 2 (ACE2) antibodies. The first case was a 59-year-old man who developed a persistent headache and fever 2weeks after SARS-CoV-2 infection. FDG-PET/CT revealed diffuse vascular inflammation extending from the carotid arteries to the abdominal aorta. The second case was a 71-year-old man who presented with prolonged fever after SARS-CoV-2 infection. Imaging demonstrated vascular wall enhancement and FDG uptake from the thoracic aorta to the iliac aorta. The third case was a 67-year-old man who had persistent fever 10days after COVID-19, with FDG-PET/CT showing uptake from the ascending aorta to the aortic arch. In all cases, workups for immune and infectious diseases were negative. Symptoms and inflammatory markers resolved spontaneously or with nonsteroidal anti-inflammatory drugs. Serum anti-ACE2 IgG was positive during the active phase in all three patients and became negative during remission. We have encountered three cases of COVID-19-associated LVV with elevated anti-ACE2 antibodies that normalized after clinical remission. There have been multiple reports of LVV following SARS-CoV-2 infection, with onset typically within weeks of infection, and of elevated anti-ACE2 antibody levels in patients with COVID-19-related neurological complications. Further studies are warranted to determine if anti-ACE2 antibodies are associated with the pathogenesis of post-COVID-19 vasculitis.

Antibody surveillance provided valuable public health insights during the Coronavirus Disease 2019 (COVID-19) pandemic. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, vaccination, and cross-reactive responses from endemic coronaviruses (human coronaviruses [HCoVs]) can influence SARS-CoV-2 antibody responses, impacting reliability and interpretation of serological findings. Here, we investigated population-level SARS-CoV-2 and HCoV IgA and IgG responses following SARS-CoV-2 infection among unvaccinated and vaccinated pregnant individuals over 3 months. Using residual sera from routine antenatal screening of pregnant individuals in British Columbia between March 2020 to May 2022, we designed a retrospective repeated cross-sectional cohort of infected individuals either unvaccinated (UV + COV, N = 171) or two- to three-dose vaccinated (V + COV, N = 137). A total of 30 pre-pandemic sera served as negative controls. Sera were collected within 3 months of respiratory PCR-positivity in half-month intervals and tested for IgA and IgG against Spike (S) of alpha-HCoV (HCoV-229E, HCoV-NL63) and beta-HCoV (HCoV-HKU1, HCoV-OC43) and S, receptor binding domain, and nucleocapsid (N) of SARS-CoV-2 using a multiplex immunoassay. Following SARS-CoV-2 infection, V + COV had lower anti-N IgG levels (P = 0.004) and seropositivity rates than UV + COV. One month post-infection, V + COV (38%) had lower anti-N IgA seropositivity than UV + COV (73%). Both groups had significantly higher anti-S IgA and IgG levels against beta-HCoV vs controls, with signals correlating positively with SARS-CoV-2 anti-S levels for each isotype. These results suggest that neither IgA nor IgG can reliably identify recent infections in vaccinated populations, emphasizing the importance of considering complex interplay of antibody responses when interpreting serological data and recognizing the potential and limitations of serological testing for diagnostics and surveillance.IMPORTANCEThis study provides key insights into how Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccination and infection shape the magnitude and longevity of IgA and IgG antibody responses following infection in pregnant individuals. It also highlights the interplay of serological responses to related viruses, such as the human coronaviruses. By leveraging population-level antenatal sera, our findings highlight important considerations for the design and interpretation of future seroprevalence studies, antibody-based surveillance, and diagnostic strategies. As SARS-CoV-2 transitions into endemic circulation, understanding the complexity of SARS-CoV-2 antibody responses provides additional insights into the strengths and limitations of serological data interpretation in a real-world setting.

This study aimed to evaluate in detail the short- and long-term humoral responses to the BNT162b2 (BioNTech, SE, Mainz, Germany/Pfizer Inc, New York, NY) vaccine in immunosuppressed children aged 5-11 years compared with healthy children. A prospective cohort study was conducted with immunosuppressed and healthy children 5-11 years of age following complete vaccination, defined as 3 doses of the BNT162b2 vaccine for immunosuppressed participants and 2 doses for healthy participants. The primary endpoints included IgG antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and receptor-binding domain, as well as neutralizing capacity, 1- and 6-months postvaccination. Secondary endpoints included evaluations of breakthrough infections and cellular immune responses against SARS-CoV-2. Thirty-five participants (20 healthy and 15 immunosuppressed) were included in the study. We could not demonstrate a different serological response in healthy children compared with immunosuppressed children in levels of anti-Spike IgG, anti-receptor-binding domain IgG, or neutralizing antibody at 1- and 6-months postvaccination. Humoral responses declined significantly by 6 months in healthy children; we could not demonstrate a significant decline in immunosuppressed children. Cellular immunity at 6 months showed a strong correlation with humoral response (R ≥ 0.74). Overall, the immunological response appeared protective for up to 6 months in both healthy and immunosuppressed participants, with only 1 breakthrough infection in a healthy child. After 3 vaccine doses, immunosuppressed children demonstrate 6-month immune comparable to healthy children who received 2 doses. Despite a decline in humoral responses over time, there were no infections, supporting the effectiveness of current coronavirus disease 2019 vaccination strategies.

To compare the characteristics, manifestations and outcome of children hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection according to the dominant variant period. We prospectively studied children 0-17 years with SARS-CoV-2 infection hospitalized for acute symptoms during 2020-2024. Multivariable logistic regression models were applied to estimate the association between variables, including onset of symptoms, fever and lower respiratory tract infection (LRTI). We studied 726 children (mean age: 3.3 years), including 81 (11.2%) with ≥1 underlying condition. Fever was the most prevalent symptom (75.1%) throughout the study; LRTI occurred in 6.9% of children. All children had a favorable outcome, and no case of mechanical ventilation or death occurred. Thirty-two children (4.4%) were admitted during the ancestral period, 45 (6.2%) during the Alpha variant, 123 (16.9%) during the Delta variant, and 526 (72.5%) during the Omicron variant periods. Children admitted during the ancestral period were less frequently symptomatic and/or febrile than those admitted in subsequent dominant variant periods (P value ≤ 0.001). Fever occurred more often at ages 3-11 months, 1-2 and 3-12 years, as compared with age 0-2 months and among children hospitalized during the Delta variant period as compared with those hospitalized in the ancestral period. Children with underlying conditions were more likely to develop LRTI as compared with children with no underlying conditions. Approximately 3 of 4 SARS-CoV-2 childhood admissions occurred during the Omicron period. Only a few cases of LRTI occurred, mostly among children with underlying conditions. All hospitalized children had a favorable outcome.

Acute febrile illness (AFI) surveillance networks can play a key role in identifying emerging pathogens and promoting global health security, especially for vulnerable populations in low- and middle-income countries. In January 2020, the Belize AFI Surveillance network was formed, and 5,643 participants were enrolled over the first 3-year period across 11 participating public hospitals. Using real-time polymerase chain reaction testing for vector-borne pathogen detection and BioFire® diagnostic testing for respiratory and gastrointestinal pathogens, the causes of illness were examined in relation to 54 pathogens in these participants. In response to the coronavirus disease 2019 pandemic, surveillance was expanded to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Overall, one or more pathogens were successfully identified in 51% of participants, with 43 different pathogens detected. Many important discoveries were made, including the first reported case of acute Chagas disease in Belize and eight cases of Vibrio cholerae . The most common identified vector-borne disease was dengue, with all four serotypes detected. The most common respiratory pathogens detected were SARS-CoV-2 and human rhinovirus/enterovirus. The most common gastrointestinal pathogens detected were different strains of diarrheagenic Escherichia coli and norovirus. These and other results obtained via AFI surveillance enabled in-country and academic partners to respond to disease outbreaks rapidly and to monitor disease activity across the country more effectively.

The worldwide dissemination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the COVID-19 pandemic, which continues to present a global threat to both healthcare workers and the wider public. Beyond the acute disease phase, many patients suffer residual symptoms (long COVID) compromising their quality of life and functional capacity. Therefore, efficacious oral antivirals that can be given early in the course have emerged as must-have tools to avert progression of severe disease, prevent hospitalizations, and perhaps avoid long-term sequela. In this review, we have collated mechanistic and clinical data for two of the oral antivirals that are widely used currently Molnupiravir and Paxlovid (Nirmatrelvir/Ritonavir) using only sources and citations that appear in the project materials. The article summarizes for each agent, chemical identity, pharmacological mechanism, pharmacokinetic considerations, clinical performance, and safety concerns. Comparisons of strengths and limitations are discussed about mechanism-based clinical decision making. Inline figures from original project files (chemical structures and mechanistic diagrams) have been included and should be included at the placeholders when preparing the final Word document. We finish the discussion with implications for therapeutic choice and outline topics for future work.

Saliva specimens are widely used for coronavirus disease 2019 (COVID-19) testing using RT-qPCR due to their advantages over nasopharyngeal swabs of being non-invasive and self-collectable. However, saliva collection can be time-consuming in individuals with reduced saliva secretion, including those with diabetes, diseases involving salivary glands such as Sjögren’s syndrome, and older adults. In this study, we evaluated the diagnostic performance of mouth rinse specimens, which can be easily collected even from individuals with reduced saliva secretion, as an alternative to saliva for RT-qPCR COVID-19 testing. Among the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive specimens analyzed, 88.2% were derived from patients possessing risk factors associated with reduced salivary secretion, including diabetes, use of medications such as anticholinergics or antihistamines, smoking, and older age. The analysis results of mouth rinse specimens demonstrated 96.7% overall agreement with those of saliva specimens, with a sensitivity of 94.1% and specificity of 100%; however, the viral load in the mouth rinse specimens was lower than that in saliva because of sample dilution. These findings suggest that mouth rinse specimens are a practical, versatile, and reliable alternative specimen for RT-qPCR COVID-19 testing.

Pathogen-specific immunity debt in children after prolonged nonpharmaceutical interventions: a cross-sectional study in China.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a respiratory viral infection that disrupts renin angiotensin system (RAS) peptide metabolism by downregulating angiotensin converting enzyme-II (ACE2), leading to accumulation of pro-inflammatory angiotensin II (AngII). We posit that angiotensin receptor blockers (ARBs) like telmisartan (TEM) can activate the pro-resolving arm of RAS (MasR/ACE2/Ang1-7), reducing lung inflammation in COVID-19 patients. In this randomized, double-blinded, placebo-controlled pilot clinical trial, outpatient SARS-CoV-2-infected study participants received either 40mg TEM or placebo once daily. Plasma inflammatory biomarker levels revealed a reduction in global systemic inflammation with TEM treatment, corresponding with an increase in MasR. We corroborated these clinical findings with in vitro analysis. A549-ACE2 lung epithelial cells treated with TEM showed increased ACE2 and MasR, as well as decreased angiotensin II receptor type I (AT1R) and angiotensin II receptor type II (AT2R) expression levels. Additionally, AngII peptide levels decreased, while Ang(1-9) and Ang(1-7) increased. TEM treatment at physiologically achievable concentration reduced SARS-CoV-2 viral load. Taken collectively, these results show TEM mediated activation of the Ang(1-7)/MasR/ACE2 pro-resolving arm of RAS, which activates anti-inflammatory events that reduce global inflammation. These findings support the use of ARBs like TEM in mitigating COVID-19 driven alterations in RAS.

B cell involvement in neoantigen-driven antitumor immunity remains largely unexplored because of challenges in predicting B cell responses. Here, we developed a method to identify B cell epitopes by characterizing >437,000 peptides tested for IgG binding and >370 million B cell receptor (BCR) clones. Our single-cell BCR sequencing of pre– and post–severe acute respiratory syndrome coronavirus 2 vaccination validates the performance of this method. Mouse vaccination experiments demonstrate that B cell neoepitopes enhance immune responses, driving BCR expansion and tumor regression. Genomic analysis of >8000 The Cancer Genome Atlas (TCGA) samples reveals an inverse correlation between predicted B cell reactivity and mutation allele frequencies, indicating B cell–mediated neoantigen elimination. Applying our multiomics model to checkpoint blockade responses in 2074 patients highlights the clinical relevance of B cell neoepitope prediction. A meta-analysis of 11 personalized vaccine trials involving 1739 neoantigens suggests that incorporating B cell neoepitopes may improve vaccination efficacy. These results underscore the significance of B cell–reactive neoantigens in antitumor immunity.

In December 2019, a new type of corona virus was discovered called Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This disease is known to first appear in Wuhan, China in December 2019 (WHO, 2020). This viral infection is called COVID-19 and is more dangerous than SARS or MERS. The purpose of this study was to determine the knowledge and attitudes of the community regarding COVID 19. This study was a quantitative study with a cross sectional design, the knowledge of the community regarding COVID 19 was said to be good because it was able to answer the questionnaire instrument correctly. The community hopes that this epidemic will end soon so that they can carry out their activities as usual. It is necessary to disseminate information related to COVID 19 to the wider community, the main symptoms. COVID-19 diseases include cough, fever, and shortness of breath. This disease affects all groups, adults, the elderly, and children.

Histopathologic placental findings in severe acute respiratory syndrome coronavirus 2 exposed gravida compared to unexposed controls: a single center retrospective cohort study.

Targeting conserved regions of the SARS-CoV-2 polymerase (RdRp) with kinase inhibitors as an effective new tactic for discovering dual-action "antiviral-antiinflammatory" drugs against COVID-19.

COVID-19 is a respiratory disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), but because the receptor protein of this virus can appear not only in the lungs and throat but also in various parts of the host's body, it causes different diseases. Recent observations have suggested that SARS-CoV-2 damages the central nervous system of patients in a manner similar to amyloid-associated neurodegenerative diseases such as Alzheimer's and Parkinson's. Neurodegenerative diseases are believed to be associated with the self-assembly of amyloid proteins and peptides. On the other hand, whole proteins or parts of them encoded by SARS-CoV-2 can form amyloid fibrils, which may play an important role in amyloid-related diseases. Motivated by this evidence, this mini-review discusses experimental and computational studies of SARS-CoV-2 proteins that can form amyloid aggregates. Liquid-Liquid Phase Separation (LLPS) is a dynamic and reversible process leading to the creation of membrane-less organelles within the cytoplasm, which is not bound by a membrane that concentrates specific types of biomolecules. These organelles play pivotal roles in cellular signaling, stress response, and the regulation of biomolecular condensates. Recently, LLPS of the Nucleocapsid (N) protein and SARS-CoV-2 RNA has been disclosed, but many questions about the phase separation mechanism and the formation of the virion core are still unclear. We summarize the results of this phenomenon and suggest potentially intriguing issues for future research.

Anti-NMDA receptor encephalitis following SARS-CoV-2 infection in children.

After severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, a minority of patients experience persistent or emerging symptoms, termed ‘long coronavirus disease (COVID)’ or post-acute sequelae of COVID-19. The molecular causes of long COVID remain unclear, but disrupted immune functions, such as inflammation and immune deficit, have been posited as factors. In this retrospective cohort study, we measured markers of immune function in a group of patients with long COVID up to 40 months post infection. As proxies for immune function, we measured serum antibody levels, antibody neutralizing capability and production of IFN gamma (IFN-γ) and IL-2 against SARS-CoV-2 and other viral peptides. As expected, serum antibody levels increased over time with vaccinations and reinfections with later variants of SARS-CoV-2. Patients also showed corresponding increasing SARS-CoV-2-specific IL-2 responses and stable IFN-γ responses. We observed no significant differences in immune responses among patients with ongoing long COVID, those who had recovered from it or individuals who recovered from acute COVID-19. Overall, we found no indication of a reduction in these aspects of immune function after SARS-CoV-2 infection. This study provides a valuable foundation for further research aimed at understanding the causes of long COVID.