Cryo-EM structure of S-Trimer, a subunit vaccine candidate for COVID-19.

Within a year after its emergence, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 100 million people worldwide with a death toll over 2 million. Vaccination remains the best hope to ultimately put this pandemic to an end. Here, using Trimer-Tag technology, we produced both wild-type (WT) and furin site mutant (MT) S-Trimers for COVID-19 vaccine studies. Cryo-EM structures of the WT and MT S-Trimers, determined at 3.2 Å and 2.6 Å respectively, revealed that both antigens adopt a tightly closed conformation and their structures are essentially identical to that of the previously solved full-length WT S protein in detergent. The tightly closed conformation is stabilized by fatty acid and polysorbate 80 binding at the receptor binding domains (RBDs) and the N terminal domains (NTDs) respectively. Additionally, we identified an important pH switch in the WT S-Trimer that shows dramatic conformational change and accounts for its increased stability at lower pH. These results validate Trimer-Tag as a platform technology in production of metastable WT S-Trimer as a candidate for COVID-19 subunit vaccine.IMPORTANCEEffective vaccine against SARS-CoV-2 is critical to end the COVID-19 pandemic. Here, using Trimer-Tag technology, we are able to produce stable and large quantities of WT S-Trimer, a subunit vaccine candidate for COVID-19 with high safety and efficacy from animal and Phase 1 clinical trial studies. Cryo-EM structures of the S-Trimer subunit vaccine candidate show that it predominately adopts tightly closed pre-fusion state, and resembles that of the native and full-length spike in detergent, confirming its structural integrity. WT S-Trimer is currently being evaluated in global Phase 2/3 clinical trial. Combining with published structures of the S protein, we also propose a model to dissect the conformation change of the spike protein before receptor binding.

Distribution and impacts on the geological environment of antiviral drugs in major waters of Wuhan, China

This study investigated water samples collected from the surface water and groundwater in Wuhan City, Hubei Province, China in different stages of the outbreak of the coronavirus disease 2019 (hereinafter referred to as COVID-19) in the city, aiming to determine the distribution characteristics of antiviral drugs in the city’s waters. The results are as follows. The main hydrochemical type of surface water and groundwater in Wuhan was Ca-HCO3. The major chemical components in the groundwater had higher concentrations and spatial variability than those in the surface water. Two antiviral drugs and two glucocorticoids were detected in the surface water, groundwater, and sewage during the COVID-19 outbreak. Among them, chloroquine phosphate and cortisone had higher detection rates of 32.26% and 25.80%, respectively in all samples. The concentrations of residual drugs in East Lake were higher than those in other waters. The main drug detected in the waters in the later stage of the COVID-19 outbreak in Wuhan was chloroquine phosphate, whose detection rates in the surface water and the groundwater were 53.85% and 28.57%, respectively. Moreover, the detection rate and concentration of chloroquine phosphate were higher in East Lake than in Huangjia Lake. The groundwater containing chloroquine phosphate was mainly distributed along the river areas where the groundwater was highly vulnerable. The residual drugs in the surface water and the groundwater had lower concentrations in the late stage of the COVID-19 outbreak than in the middle of the outbreak, and they have not yet caused any negative impacts on the ecological environment.©2022 China Geology Editorial Office.

[Application and Research Progress of Video Double-lumen Tube in Thoracic Surgery].

The rapid development and promotion of minimally invasive thoracic surgery represented by video-assisted thoracoscopy surgery has gradually replaced traditional thoracic surgery technique as the primary choice for the treatment of pulmonary nodules, including early lung cancer. With the clinical application of double-lumen bronchial catheters, the realization of one-lung ventilation technology not only provides a solid anesthesia foundation for the popularization of minimally invasive thoracic surgery, but also provides a guarantee for the rapid and smooth implementation of the operation. However, compared with single-lumen bronchial catheters, the diameter of the double-lumen bronchial catheter is thicker, and the tube body is hard and difficult to shape, which brings inconvenience to anesthesia intubation. The bronchial structure is different, and the incidence of dislocation during anesthesia intubation is also high. With the gradual clinical use of video double-lumen tube (VDLT), it has become a hot spot in thoracic surgery in recent years. This article reviews the application and research progress of VDLT in thoracic surgery.
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Psychological Impact and Workload of COVID-19 on Healthcare Workers in China During the Early Time of the Pandemic: A Cross-sectional Study.

OBJECTIVE: This study aimed to investigate the organization, workload, and psychological impact of COVID-19 on healthcare workers from the domestic Medical Aid Teams (MATs) sent to Wuhan in China. METHODS: Leaders and members of MATs involved in the care for COVID-19 patients were invited to participate in a study by completing 2 separate self-report questionnaires from April 1 to 24, 2020. RESULTS: A total of 9 MAT leaders were involved and 464 valid questionnaires were collected from 140 doctors and 324 nurses. Mean age of the doctors and nurses were 39.34 ± 6.70 (26∼58 years old) and 31.88 ± 5.29 (21∼52 years old), with 72 (15.5%) being males. Nurses were identified as an independent risk factor (HR 1.898; P = 0.001) for a day working time in the multivariate analysis. The proportions of psychological consulting received among nurses were higher than those among doctors (49.7 vs 30.0%, P < 0.001). More than 50% of the anesthetists and emergency doctors who have received psychological consulting thought that it was effective according to self-evaluation. CONCLUSIONS: This study focused on healthcare workers' situation during the early period of the pandemic. Nurses worked longer than doctors. The effectiveness of psychological consulting depends on the physicians' specialties and the working conditions of the nurses and psychological consulting targeting different specialties need to be improved.

Persistence of SARS-CoV-2 RNA in wastewater after the end of the COVID-19 epidemics.

Although the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been widely detected in wastewater in many countries to track the COVID-19 pandemic development, it is still a lack of clear understanding of the persistence of SARS-CoV-2 in raw sewage, especially after the end of the COVID-19 pandemic event. To fill this knowledge gap, this study conducted a field trial on the SARS-CoV-2 presence in various wastewater facilities after the end of the COVID-19 epidemics in Beijing. The result showed that the wastewater treatment facility is a large SARS-CoV-2 repository. The viral RNA was still present in hospital sewage for 15 days and was continually detected in municipal WWTPs for more than 19 days after the end of the local COVID-19 epidemics. The T90 values of the SARS-CoV-2 RNA in raw wastewater were 17.17-8.42 days in the wastewater at 4 â„ƒ and 26 â„ƒ, respectively, meaning that the decay rates of low titer viruses in raw sewage were much faster. The results confirmed that the SARS-CoV-2 RNA could persist in wastewater for more than two weeks, especially at lower temperatures. The sewage systems would be a virus repository and prolong the presence of the residual SARS-CoV-2 RNA. The study could enhance further understanding of the presence of SARS-CoV-2 RNA in raw wastewater.

Persistence of the Immune Responses and Cross-Neutralizing Activity With Variants of Concern Following 2 Doses of Adjuvanted SCB-2019 Coronavirus Disease 2019 Vaccine.

BACKGROUND: We have previously reported the safety and immunogenicity 4 weeks after 2 doses of the Clover coronavirus disease 2019 (COVID-19) vaccine candidate, SCB-2019, a stabilized prefusion form of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein (S-trimer). We now report persistence of antibodies up to 6 months after vaccination, and cross-neutralization titers against 3 variants of concern (VoCs). METHODS: In a phase 1 study, adult (18-54 years of age) and elderly (55-75 years of age) volunteers received 2 vaccinations 21 days apart with placebo or 3-, 9-, or 30-µg. We measured immunoglobulin G (IgG) antibodies against SCB-2019, angiotensin-converting enzyme 2 (ACE2) competitive binding antibodies, and neutralizing antibodies against wild-type SARS-CoV-2 (Wuhan-Hu-1) at days 101 and 184, and neutralizing antibodies against 3 VoCs, Alpha (B.1.1.7), Beta (B.1.351), and Gamma (P.1), in day 36 sera. RESULTS: Titers waned from their peak at days 36-50, but SCB-2019 IgG antibodies, ACE2 competitive binding antibodies, and neutralizing antibodies against wild-type SARS-CoV-2 persisted at 25%-35% of their observed peak levels at day 184. Day 36 sera also demonstrated dose-dependent increases in neutralizing titers against the 3 VoCs. CONCLUSIONS: SCB-2019 dose-dependently induced immune responses against wild-type SARS-CoV-2, which persisted up to day 184. Neutralizing antibodies were cross-reactive against 3 of the most prevalent VoCs.

COVID-19 Vaccine Uptake, Acceptance, and Hesitancy Among Persons With Mental Disorders During the Second Stage of China's Nationwide Vaccine Rollout.

Persons with mental disorders (PwMDs) are a priority group for COVID-19 vaccination, but empirical data on PwMDs' vaccine uptake and attitudes toward COVID-19 vaccines are lacking. This study examined the uptake, acceptance, and hesitancy associated with COVID-19 vaccines among Chinese PwMDs during China's nationwide vaccine rollout. In total, 906 adult PwMDs were consecutively recruited from a large psychiatric hospital in Wuhan, China, and administered a self-report questionnaire, which comprised standardized questions regarding sociodemographics, COVID-19 vaccination status, attitudes toward COVID-19 vaccines, and psychopathology. Vaccine-recipients were additionally asked to report adverse events that occurred following vaccination. PwMDs had a much lower rate of vaccination than Wuhan residents (10.8 vs. 40.0%). The rates of vaccine acceptance and hesitancy were 58.1 and 31.1%, respectively. Factors associated with vaccine uptake included having other mental disorders [odds ratio (OR) = 3.63], believing that ≥50% of vaccine-recipients would be immune to COVID-19 (OR = 3.27), being not worried about the side effects (OR = 2.59), and being an outpatient (OR = 2.24). Factors associated with vaccine acceptance included perceiving a good preventive effect of vaccines (OR = 12.92), believing that vaccines are safe (OR = 4.08), believing that ≥50% of vaccine-recipients would be immune to COVID-19 (OR = 2.20), and good insight into the mental illness (OR = 1.71). Adverse events occurred in 21.4% of vaccine-recipients and exacerbated pre-existing psychiatric symptoms in 2.0% of vaccine-recipients. Nevertheless, 95.2% of vaccine-recipients rated adverse events as acceptable. Compared to the 58.1% vaccine acceptance rate and the 40.0% vaccination rate in the general population, the 10.8% vaccine coverage rate suggested a large unmet need for COVID-19 vaccination in Chinese PwMDs. Strategies to increase vaccination coverage among PwMDs may include provision of reliable sources of information on vaccines, health education to foster positive attitudes toward vaccines, a practical guideline to facilitate clinical decision-making for vaccination, and the involvement of psychiatrists in vaccine consultation and post-vaccination follow-up services.

Probable airborne transmission of SARS-CoV-2 in a poorly ventilated restaurant.

Although airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been recognized, the condition of ventilation for its occurrence is still being debated. We analyzed a coronavirus disease 2019 (COVID-19) outbreak involving three families in a restaurant in Guangzhou, China, assessed the possibility of airborne transmission, and characterized the associated environmental conditions. We collected epidemiological data, obtained a full video recording and seating records from the restaurant, and measured the dispersion of a warm tracer gas as a surrogate for exhaled droplets from the index case. Computer simulations were performed to simulate the spread of fine exhaled droplets. We compared the in-room location of subsequently infected cases and spread of the simulated virus-laden aerosol tracer. The ventilation rate was measured using the tracer gas concentration decay method. This outbreak involved ten infected persons in three families (A, B, C). All ten persons ate lunch at three neighboring tables at the same restaurant on January 24, 2020. None of the restaurant staff or the 68 patrons at the other 15 tables became infected. During this occasion, the measured ventilation rate was 0.9 L/s per person. No close contact or fomite contact was identified, aside from back-to-back sitting in some cases. Analysis of the airflow dynamics indicates that the infection distribution is consistent with a spread pattern representative of long-range transmission of exhaled virus-laden aerosols. Airborne transmission of the SARS-CoV-2 virus is possible in crowded space with a ventilation rate of 1 L/s per person.

S-Trimer, a COVID-19 subunit vaccine candidate, induces protective immunity in nonhuman primates.

SARS-CoV-2 is the underlying cause for the COVID-19 pandemic. Like most enveloped RNA viruses, SARS-CoV-2 uses a homotrimeric surface antigen to gain entry into host cells. Here we describe S-Trimer, a native-like trimeric subunit vaccine candidate for COVID-19 based on Trimer-Tag technology. Immunization of S-Trimer with either AS03 (oil-in-water emulsion) or CpG 1018 (TLR9 agonist) plus alum adjuvants induced high-level of neutralizing antibodies and Th1-biased cellular immune responses in animal models. Moreover, rhesus macaques immunized with adjuvanted S-Trimer were protected from SARS-CoV-2 challenge compared to vehicle controls, based on clinical observations and reduction of viral loads in lungs. Trimer-Tag may be an important platform technology for scalable production and rapid development of safe and effective subunit vaccines against current and future emerging RNA viruses.

Safety and immunogenicity of S-Trimer (SCB-2019), a protein subunit vaccine candidate for COVID-19 in healthy adults: a phase 1, randomised, double-blind, placebo-controlled trial.

BACKGROUND: As part of the accelerated development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we report a dose-finding and adjuvant justification study of SCB-2019, a protein subunit vaccine candidate containing a stabilised trimeric form of the spike (S)-protein (S-Trimer) combined with two different adjuvants. METHODS: Our study is a phase 1, randomised, double-blind placebo-controlled trial at a specialised clinical trials centre in Australia. We enrolled healthy adult volunteers in two age groups: younger adults (aged 18-54 years) and older adults (aged 55-75 years). Participants were randomly allocated either vaccine or placebo using a list prepared by the study funder. Participants were to receive two doses of SCB-2019 (either 3 µg, 9 µg, or 30 µg) or a placebo (0·9% NaCl) 21 days apart. SCB-2019 either had no adjuvant (S-Trimer protein alone) or was adjuvanted with AS03 or CpG/Alum. The assigned treatment was administered in opaque syringes to maintain masking of assignments. Reactogenicity was assessed for 7 days after each vaccination. Humoral responses were measured as SCB-2019 binding IgG antibodies and ACE2-competitive blocking IgG antibodies by ELISA and as neutralising antibodies by wild-type SARS-CoV-2 microneutralisation assay. Cellular responses to pooled S-protein peptides were measured by flow-cytometric intracellular cytokine staining. This trial is registered with ClinicalTrials.gov, NCT04405908; this is an interim analysis and the study is continuing. FINDINGS: Between June 19 and Sept 23, 2020, 151 volunteers were enrolled; three people withdrew, two for personal reasons and one with an unrelated serious adverse event (pituitary adenoma). 148 participants had at least 4 weeks of follow-up after dose two and were included in this analysis (database lock, Oct 23, 2020). Vaccination was well tolerated, with two grade 3 solicited adverse events (pain in 9 µg AS03-adjuvanted and 9 µg CpG/Alum-adjuvanted groups). Most local adverse events were mild injection-site pain, and local events were more frequent with SCB-2019 formulations containing AS03 adjuvant (44-69%) than with those containing CpG/Alum adjuvant (6-44%) or no adjuvant (3-13%). Systemic adverse events were more frequent in younger adults (38%) than in older adults (17%) after the first dose but increased to similar levels in both age groups after the second dose (30% in older and 34% in younger adults). SCB-2019 with no adjuvant elicited minimal immune responses (three seroconversions by day 50), but SCB-2019 with fixed doses of either AS03 or CpG/Alum adjuvants induced high titres and seroconversion rates of binding and neutralising antibodies in both younger and older adults (anti-SCB-2019 IgG antibody geometric mean titres at day 36 were 1567-4452 with AS03 and 174-2440 with CpG/Alum). Titres in all AS03 dose groups and the CpG/Alum 30 µg group were higher than were those recorded in a panel of convalescent serum samples from patients with COVID-19. Both adjuvanted SCB-2019 formulations elicited T-helper-1-biased CD4+ T-cell responses. INTERPRETATION: The SCB-2019 vaccine, comprising S-Trimer protein formulated with either AS03 or CpG/Alum adjuvants, elicited robust humoral and cellular immune responses against SARS-CoV-2, with high viral neutralising activity. Both adjuvanted vaccine formulations were well tolerated and are suitable for further clinical development. FUNDING: Clover Biopharmaceuticals and the Coalition for Epidemic Preparedness Innovations.

Clinical features in mild type and severe type of COVID-19 patients (preprint)

Background Coronavirus Disease 2019 (COVID-19) outbroke in Wuhan and spread to the world quickly. We aim to describe the clinical features and compare them between mild type and severe type of COVID-19 patients.Methods Laboratory confirmed COVID-19 patients were included in this study. Patients’ demographic data and clinical data were recorded and compared between mild type and severe type.Results Fifteen patients were confirmed COVID-19 and enrolled in this study. Six patients were of mild type, while 9 patients were of severe type. Statistical differences were found between mild type and severe type patients in retirement, epidemiological history, baseline blood level of lactate dehydrogenase and Oxygenation Index (All p < 0.05). All patients had ground-glass opacities without consolidation in initial chest computed tomography images, 2 (16.7%) patients had pulmonary nodules. There were no statistical differences between mild type and severe type patients in initial chest CT findings (All p > 0.05).Conclusions Differences can be found in baseline clinical features between mild type and severe type of COVID-19 patients to help health care providers making early judgement to the severity and proper treatment.Trial registration: The study was registered in ClinicalTrials.gov, NCT04279782. Registered 20 February 2020 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04279782?term=NCT04279782&draw=2&rank=1

Immunity-and-Matrix-Regulatory Cells Derived from Human Embryonic Stem Cells Safely and Effectively Treat Mouse Lung Injury and Fibrosis (preprint)

Lung injury and fibrosis represent the most significant outcomes of severe and acute lung disorders, including COVID-19. However, there are still no effective drugs to treat lung injury and fibrosis. In this study, we report the generation of clinical-grade human embryonic stem cells (hESCs)-derived immunity- and matrix-regulatory cells (IMRCs) produced under good manufacturing practice (GMP) requirements, that can treat lung injury and fibrosis in vivo. We generate IMRCs by sequentially differentiating hESCs with serum-free reagents. IMRCs possess a unique gene expression profile distinct from umbilical cord mesenchymal stem cells (UCMSCs), such as higher levels of proliferative, immunomodulatory and anti-fibrotic genes. Moreover, intravenous delivery of IMRCs inhibits both pulmonary inflammation and fibrosis in mouse models of lung injury, and significantly improves the survival rate of the recipient mice in a dose-dependent manner, likely through paracrine regulatory mechanisms. IMRCs are superior to both primary UCMSCs and FDA-approved pirfenidone, with an excellent efficacy and safety profile in mice and monkeys. In light of public health crises involving pneumonia, acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), our findings suggest that IMRCs are ready for clinical trials on lung disorders.

Clinical features in mild type and severe type of COVID-19 patients (preprint)

Background: Coronavirus Disease 2019 (COVID-19) outbroke in Wuhan and spread to the world quickly. We aim to describe the clinical features and compare them between mild type and severe type of COVID-19 patients. Methods: Laboratory confirmed COVID-19 patients were included in this study. Patients’ demographic data and clinical features were recorded and compared between mild type and severe type. Results: Fifteen patients were confirmed COVID-19 and enrolled in this study. Six patients were of mild type, while 9 patients were of severe type. Statistical differences were found between mild type and severe type patients in retirement, epidemiological history, baseline blood level of lactate dehydrogenase and Oxygenation Index (All p < 0.05). All patients had ground-glass opacities without consolidation in initial chest computed tomography images, 2 (16.7%) patients had pulmonary nodules. There were no statistical differences between mild type and severe type patients in initial chest CT findings (All p > 0.05). Conclusions: Differences can be found in baseline clinical features between mild type and severe type of COVID-19 patients to help health care providers making early judgement to the severity and proper treatment. Trial registration: The study was registered in ClinicalTrials.gov, NCT04279782. Registered 20 February 2020 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04279782?term=NCT04279782&draw=2&rank=1

More than six weeks to resolve from CT manifestations in COVID-19 patient: A case report (preprint)

Background: Coronavirus Disease 2019 (COVID-19) outbroke in Wuhan and spread to the world recently. But there were little studies on how long it took to recover from treatment beginning and resolve from chest computed tomography (CT) imaging so far.Case presentation: A patient diagnosed with severe type of COVID-19 was reported in this study. He was the first patient recovered and discharged from our hospital located in Guangzhou city. Initial chest computed tomography (CT) images of him showed bilateral multiple lobular peripheral ground-glass opacities without consolidation. Features and changes of his chest CT images from admission to discharge and follow-up were demonstrated. It took more than six weeks for lesion resolution in CT manifestations although the symptoms improved for a period of time after proper treatment. Conclusions: Repeated chest CT imaging for a period of more than six weeks in patients of COVID-19 is necessary to ascertain the lesion resolution and completely recovery. The result could be supplementary data to COVID-19 and help health care providers manage the COVID-19 patients.

2019 Novel Coronavirus can be detected in urine, blood, anal swabs and oropharyngeal swabs samples (preprint)

We tested samples collected from nine patients diagnosed with coronavirus disease 2019 (COVID-19). The virus was found in urine, blood, anal swabs and oropharyngeal swabs. It is the first time for SARS-CoV-2 found in urine, though no urinary irritation was found.