Molnupiravir Use and 30-Day Hospitalizations or Death in Previously Uninfected Non-hospitalized High-risk Population with COVID-19.

BACKGROUND: Clinical benefit of Molnupiravir (MPV) in COVID-19 infected sub-populations is unclear. METHODS: We used a matched cohort study design to determine the rate of hospitalization or death within 30 days of COVID-19 diagnosis among MPV treated and untreated controls. Participants were non-hospitalized, previously uninfected Veterans with a first confirmed SARS-CoV-2 infection between January 1 and August 31, 2022, who were prescribed MPV within 3 days of COVID-19 diagnosis, and matched individuals who were not prescribed MPV. RESULTS: Among 1,459 matched pairs, the incidence of hospitalization/death was not different among MPV treated vs. untreated controls (48 vs. 44 cases; ARD [95% CI] 0.27 [-0.94,1.49]). No benefit was observed among those >60 or ≤60 years old (ARD 0.27 [-1.25,1.79] vs. -0.29 [-1.22,1.80]), those with specific comorbidities, or by vaccination status. A significant benefit was observed in asymptomatic but not in symptomatic persons (ARD -2.80 [-4.74, -0.87] vs. 1.12 [-0.31,2.55]). Kaplan-Meier curves did not show a difference in proportion of persons who were hospitalized or died among MPV treated compared with untreated controls (logrank P = 0.7). CONCLUSION: MPV was not associated with a reduction in hospitalization or death within 30 days of COVID-19 diagnosis. A subgroup of patients presenting without symptoms experienced a benefit.

Tracking of Mutational Signature of SARS-CoV-2 Omicron on Distinct Continents and Little Difference was Found.

The Omicron variant is currently ravaging the world, raising serious concern globally. Monitoring genomic variations and determining their influence on biological features are critical for tracing its ongoing transmission and facilitating effective measures. Based on large-scale sequences from different continents, this study found that: (i) The genetic diversity of Omicron is much lower than that of the Delta variant. Still, eight deletions (Del 1-8) and 1 insertion, as well as 130 SNPs, were detected on the Omicron genomes, with two deletions (Del 3 and 4) and 38 SNPs commonly detected on all continents and exhibiting high-occurring frequencies. (ii) Four groups of tightly linked SNPs (linkage I-IV) were detected, among which linkage I, containing 38 SNPs, with 6 located in the RBD, increased its occurring frequency remarkably over time. (iii) The third codons of the Omicron shouldered the most mutation pressures, while the second codons presented the least flexibility. (iv) Four major mutants with amino acid substitutions in the RBD were detected, and further structural analysis suggested that the substitutions did not alter the viral receptor binding ability greatly. It was inferred that though the Omicron genome harbored great changes in antigenicity and remarkable ability to evade immunity, it was immune-pressure selected. This study tracked mutational signatures of Omicron variant and the potential biological significance of the SNPs, and the linkages await further functional verification.

Changes in endemic patterns of respiratory syncytial virus infection in pediatric patients under the pressure of nonpharmaceutical interventions for COVID-19 in Beijing, China.

A series of nonpharmaceutical interventions (NPIs) was launched in Beijing, China, on January 24, 2020, to control coronavirus disease 2019. To reveal the roles of NPIs on the respiratory syncytial virus (RSV), respiratory specimens collected from children with acute respiratory tract infection between July 2017 and Dec 2021 in Beijing were screened by capillary electrophoresis-based multiplex PCR (CEMP) assay. Specimens positive for RSV were subjected to a polymerase chain reaction (PCR) and genotyped by G gene sequencing and phylogenetic analysis using iqtree v1.6.12. The parallel and fixed (paraFix) mutations were analyzed with the R package sitePath. Clinical data were compared using SPSS 22.0 software. Before NPIs launched, each RSV endemic season started from October/November to February/March of the next year in Beijing. After that, the RSV positive rate abruptly dropped from 31.93% in January to 4.39% in February 2020; then, a dormant state with RSV positive rates ≤1% from March to September, a nearly dormant state in October (2.85%) and November (2.98%) and a delayed endemic season in 2020, and abnormal RSV positive rates remaining at approximately 10% in summer until September 2021 were detected. Finally, an endemic RSV season returned in October 2021. There was a game between Subtypes A and B, and RSV-A replaced RSV-B in July 2021 to become the dominant subtype. Six RSV-A and eight RSV-B paraFix mutations were identified on G. The percentage of severe pneumonia patients decreased to 40.51% after NPIs launched. NPIs launched in Beijing seriously interfered with the endemic season of RSV.

The effect of COVID-19 on referral patterns for clinical electrophysiological testing.

PURPOSE: To provide an overview of the effect that the COVID-19 pandemic has had on visual electrophysiology referral patterns and the subsequent effect this may have on patients. METHODS: All electrodiagnostic tests performed at Kensington Vision and Research Centre, Toronto Canada, in a 3-month period prior to the COVID-19 pandemic (1 September 2019 to 30 November 2019) were compared to a 3-month period after the start of the COVID-19 pandemic (1 September 2021 to 30 November 2021). RESULTS: A total of 502 patients had electrodiagnostic testing carried out in the designated time periods: 292 in the time period prior to the COVID-19 pandemic and 210 patients after. There was a significant change in the reason for referral in patients pre-COVID compared to post-COVID (p = 0.004). There was a 43% reduction in referrals for drug monitoring, 25% reduction for hereditary pathology and a 27% increase in acquired pathology after the start of the COVID-19 pandemic compared to before. CONCLUSIONS: There was a substantial decrease in the total number of patients referred after the start of the COVID-19 pandemic compared to pre-COVID with inherited retinal pathology and drug monitoring patients being 2 populations most affected by the disruption to healthcare services.

Real-World Effectiveness of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA Vaccines in Preventing Confirmed Infection in Patients on Chronic Hemodialysis.

BACKGROUND: Persons on chronic hemodialysis have a significantly diminished humoral immune response to SARS-CoV-2 vaccines. Whether this translates to reduced vaccine effectiveness (VE) is unknown. METHODS: We used the US Department of Veterans Affairs COVID-19 Shared Data Resource to identify all veterans who were tested for SARS-CoV-2 between 26 January and 31 August 2021. Using International Classification of Diseases, 10th edition, codes and attendance at a dialysis clinic/center, we identified those who were on chronic hemodialysis. We used a test-negative, case-control design using a doubly robust logistic regression model to determine the VE of the BNT-162b2 (Pfizer) or mRNA-1273 (Moderna) vaccines in preventing confirmed SARS-CoV-2 infection. RESULTS: Among 847 199 veterans tested for SARS-CoV-2 between 26 January and 31 August 2021, there were 6076 veterans on chronic hemodialysis. Among those, we identified 1270 cases (580 fully vaccinated) and 2959 controls (2120 fully vaccinated). The overall VE >14 days after the second dose in preventing documented infection was 68.2% (95% CI: 62.6-72.9%). VE was 68.9% (95% CI: 61.9-74.7%) for Pfizer BNT-162b2 and 66.7% (95% CI: 58.9-73.0%) for Moderna mRNA-1273 vaccine. There was no difference in VE by age (<70 vs >70 years), race, or sex. There were no events recorded in persons with a Charlson's comorbidity index score <2. CONCLUSIONS: VE of 2 doses of current mRNA vaccines in preventing SARS-CoV-2 infection in persons on chronic hemodialysis is lower than historic VE rates in the general population. Effects of additional doses in improving VE in this special population need further study.

Rate and Risk Factors for Severe/Critical Disease Among Fully Vaccinated Persons With Breakthrough Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection in a High-Risk National Population.

BACKGROUND: Breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections after vaccination have been reported. Outcomes among persons with breakthrough infection are poorly understood. METHODS: We identified all veterans with a confirmed SARS-CoV-2 infection >14 days after the second dose of an mRNA vaccine between 15 December 2020 and 30 June 2021 and propensity score-matched unvaccinated controls with SARS-CoV-2 infection. The primary outcome was severe/critical disease, defined as admission to an intensive care unit, need for mechanical ventilation, or death within 28 days of diagnosis or during index hospitalization. RESULTS: Among 502 780 vaccinated and 599 974 unvaccinated persons, there were 2332 (0.5%) breakthrough infections in the vaccinated group and 40 540 (6.8%) infections in the unvaccinated group over a follow-up period of 69 083 person-days in each group. Among these groups, we identified 1728 vaccinated persons with breakthrough infection (cases) and 1728 propensity score-matched unvaccinated controls with infection. Among the former, 95 (5.5%) persons met the criteria for severe/critical disease, while 200 (11.6%) persons met the criteria among the latter group. The incidence rate for severe/critical disease per 1000 person-days (95% confidence interval [CI]) was .55 (.45-.68) among vaccinated persons with breakthrough infection and 1.22 (1.07-1.41) among the unvaccinated matched controls who developed infection (P < .0001). Risk was higher; the hazard ratio (95% CI) with increasing age per 10-year increase was 1.25 (1.11-1.41); for those with >4 comorbidities, it was 2.85 (1.49-5.43), while being vaccinated was associated with strong protection against severe/critical disease (HR, 0.41; 95% CI: .32-.52). CONCLUSIONS: The rate of severe/critical disease is higher among older persons and those with >4 comorbidities but lower among fully vaccinated persons with breakthrough infection compared with unvaccinated controls who develop infection.

Comparison of demographic features and laboratory parameters between COVID-19 deceased patients and surviving severe and critically ill cases.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has been far more devastating than expected, showing no signs of slowing down at present. Heilongjiang Province is the most northeastern province of China, and has cold weather for nearly half a year and an annual temperature difference of more than 60ºC, which increases the underlying morbidity associated with pulmonary diseases, and thus leads to lung dysfunction. The demographic features and laboratory parameters of COVID-19 deceased patients in Heilongjiang Province, China with such climatic characteristics are still not clearly illustrated. AIM: To illustrate the demographic features and laboratory parameters of COVID-19 deceased patients in Heilongjiang Province by comparing with those of surviving severe and critically ill cases. METHODS: COVID-19 deceased patients from different hospitals in Heilongjiang Province were included in this retrospective study and compared their characteristics with those of surviving severe and critically ill cases in the COVID-19 treatment center of the First Affiliated Hospital of Harbin Medical University. The surviving patients were divided into severe group and critically ill group according to the Diagnosis and Treatment of New Coronavirus Pneumonia (the seventh edition). Demographic data were collected and recorded upon admission. Laboratory parameters were obtained from the medical records, and then compared among the groups. RESULTS: Twelve COVID-19 deceased patients, 27 severe cases and 26 critically ill cases were enrolled in this retrospective study. No differences in age, gender, and number of comorbidities between groups were found. Neutrophil percentage (NEUT%), platelet (PLT), C-reactive protein (CRP), creatine kinase isoenzyme (CK-MB), serum troponin I (TNI) and brain natriuretic peptides (BNP) showed significant differences among the groups (P = 0.020, P = 0.001, P < 0.001, P = 0.001, P < 0.001, P < 0.001, respectively). The increase of CRP, D-dimer and NEUT% levels, as well as the decrease of lymphocyte count (LYMPH) and PLT counts, showed significant correlation with death of COVID-19 patients (P = 0.023, P = 0.008, P = 0.045, P = 0.020, P = 0.015, respectively). CONCLUSION: Compared with surviving severe and critically ill cases, no special demographic features of COVID-19 deceased patients were observed, while some laboratory parameters including NEUT%, PLT, CRP, CK-MB, TNI and BNP showed significant differences. COVID-19 deceased patients had higher CRP, D-dimer and NEUT% levels and lower LYMPH and PLT counts.

Delayed anti-VEGF injections during the COVID-19 pandemic and changes in visual acuity in patients with three common retinal diseases: A systematic review and meta-analysis.

The COVID-19 pandemic disrupted the regular injections of anti-vascular endothelial growth factor (anti-VEGF) in patients with various retinal diseases globally. It is unclear to what extent delayed anti-VEGF injections have worsened patients' visual acuity. We performed a meta-analysis to assess the impact of delayed anti-VEGF injections on the best-corrected visual acuity (BCVA) in patients with neovascular age-related macular degeneration (nAMD), retinal vein occlusion (RVO), and diabetic macular edema (DME). We searched four computer databases (EMBASE, MEDLINE, Web of Science, Scopus) from inception to January 5, 2022. Data were pooled using the random-effects model. Results were reported by less than 4 months and 4 months or longer for the time period between the first injection during the pandemic and the last pre-pandemic injection. All BCVA measures were converted to the logarithm of the minimum angle of resolution (logMAR) for analyses. Among patients who received injections 4 months or longer apart, the mean difference in BCVA was 0.10 logMAR (or 5 ETDRS letters) (95% confidence interval [CI] 0.06∼0.14) for nAMD patients, 0.01 logMAR (or∼ 1 ETDRS letter) (95% CI -0.25∼0.27) for RVO patients, and 0.03 logMAR (or ∼1 ETDRS letters) (95% CI -0.06∼0.11) for DME patients. These results suggest that patients with nAMD needing scheduled anti-VEGF injections may require priority treatment over those with RVO and DME in the event of disturbed anti-VEGF injections from COVID-19 lockdowns or similar scenarios.

ENDOGENOUS FUNGAL ENDOPHTHALMITIS FOLLOWING COVID-19 INFECTION: CASE REPORT AND REVIEW OF LITERATURE.

PURPOSE: To describe a case of endogenous endophthalmitis (EE) following severe COVID-19 disease, review patient outcomes with EE following COVID-19 infection, review evidence regarding risk factors for developing EE. METHODS: Review of health records, imaging, intravitreal injection, and pars plana vitrectomy for bilateral fungal EE following severe COVID-19 disease. Literature review on outcomes in EE following COVID-19 disease. RESULTS: 63 year-old male with diabetes and hypertension was admitted to hospital for severe COVID-19 disease for 3 months. His stay required ICU admission, intubation, high-dose corticosteroids, tocilizumab, and was complicated by bacteremia, empyema, and fungal esophagitis. He developed floaters and bilateral vision loss (visual acuity 20/40 OD, CF OS) with vitritis 2.5 months into his stay that did not respond to intravitreal voriconazole. Pars plana vitrectomy was performed for both eyes, resulting in visual acuity of 20/40 OD, 20/30 OS. Vitreous cultures were positive for candida albicans. EE following COVID-19 disease has been reported in 22 patients to date, and outcomes are poor, with 40%+ of eyes legally blind (20/200 or worse). Although influenced by availability of imaging modalities and degree of training of the evaluating physician, misdiagnosis can affect » of cases, delaying treatment. Age, male gender, and diabetes increase risk of severe COVID-19, which requires prolonged hospitalization, invasive catheretization, and immunosuppression, which in turn increases risk of nosocomial infection. CONCLUSION: Low threshold for suspecting endogenous endophthalmitis in patients presenting with floaters and decreased vision following severe COVID-19 disease is necessary to ensure prompt recognition and treatment.

[Clinical observation on filiform-fire needling of "Biaoben acupoint combination" for 33 cases of sequelae of coronavirus disease 2019 during recovery period].

OBJECTIVE: To observe the clinical therapeutic effect of filiform-fire needling of "Biaoben acupoint combination" on the sequelae of patients with coronavirus disease 2019 (COVID-19) during the recovery period. METHODS: A total of 33 patients with COVID-19 during the recovery period were treated with filiform-fire needling at the acupoints of Mingmen (GV 4), Shenzhu (GV 12), Gaohuang (BL 43), Zusanli (ST 36) and Shangjuxu (ST 37), etc., once every other day, 3 times a week, and 3 times was one course of treatment and totally 2 courses of treatment were required. The TCM symptom, Hamilton anxiety scale (HAMA) and Hamilton depression scale (HAMD) scores, pulmonary function indexes (forced vital capacity [FVC], forced expiratory volume in one second [FEV1], peak expiratory flow [PEF]) and chest CT imaging change were observed before and after treatment, and the therapeutic effect was evaluated. RESULTS: After treatment, the scores of TCM symptom, HAMA and HAMD were decreased compared with those before treatment (P<0.05), and the levels of FVC, FEV1 and PEF were increased compared with those before treatment (P<0.05), and the recovery rate of 22 patients with pulmonary ventilation dysfunction was 86.4% (19/22). After treatment, the lung shadow area was smaller than that before treatment (P<0.05). The effective rate of 25 patients with lung CT abnormalities was 84.0% (21/25). After treatment, 23 cases were cured, 5 cases were markedly effective, 4 cases were effective, 1 case was ineffective, the cured and markedly effective rate was 84.8%. CONCLUSION: The filiform-fire needling of "Biaoben acupoint combination" could significantly reduce the sequelae of cough, fatigue, chest tightness, etc. and mental symptoms such as anxiety and depression in patients with COVID-19 during the recovery period, and promote inflammatory exudation absorption of pulmonary lesion and improve lung ventilation function.

Behavioral Intention and Its Predictors toward COVID-19 Booster Vaccination among Chinese Parents: Applying Two Behavioral Theories

The booster vaccination of COVID-19 is being implemented in most parts of the world. This study used behavioral psychology to investigate the predictors of parents' intentions regarding the COVID-19 booster vaccination for their children. This is a cross-sectional study with a self-designed questionnaire based on two behavioral theories-protective motivation theory (PMT) and theory of planned behavior (TPB). A stratified multi-stage sampling procedure was conducted in Nanjing, China, and multivariable regression analyses were applied to examine the parents' intentions. The intention rate was 87.3%. The response efficacy (ORa = 2.238, 95% CI: 1.360–3.682) and response cost (ORa = 0.484, 95% CI: 0.319–0.732) in the PMT, were significant psychological predictors of parents' intentions, and so were the attitude (ORa = 2.619, 95% CI: 1.480–4.636) and behavioral control (ORa = 3.743, 95% CI: 2.165–6.471) in the TPB. The findings of crucial independent predictors in the PMT and TPB constructs inform the evidence-based formulation and implementation of strategies for booster vaccination in children.

Vaccine Effectiveness of 3 Versus 2 Doses of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA Vaccines in a High-Risk National Population.

BACKGROUND: Knowledge of the vaccine effectiveness (VE) of a third or booster vaccine dose in preventing SARS-CoV-2 infection or its consequences is critical in developing recommendations for their use. We determined relative VE of 3 vs 2 doses of an mRNA vaccine in preventing symptomatic SARS-CoV-2 infection, hospitalization, and severe/critical disease. METHODS: Among veterans who had received 2 doses of an mRNA vaccine by 30 April 2021, we identified those who received a third dose of the same vaccine between 22 September and 24 November 2021 and 1:1 matched controls who had not received their third dose by then. Using Cox proportional hazards model, we calculated adjusted hazards ratios for symptomatic infection, hospitalization, and intensive care unit (ICU) admission or death after SARS-CoV-2-positive test. RESULTS: Among 2 321 366 veterans who received 2 doses of Pfizer BNT-162b2 or Moderna mRNA-1273 vaccine by 30 April 2021, we matched 395 686 persons who received a third dose of the same vaccine between 22 September and 24 November 2021 to controls who did not receive a third dose. Adjusted HRs (95% CI) were .15 (.11-.21) for symptomatic infection and .18 (.13-.26) for hospitalizations for 3 vs 2 doses, corresponding to relative VE of 85% and 82%. Five ICU admissions or deaths were observed (4 among recipients of 2 doses). There was no difference in VE between BNT162b2 versus mRNA-1273 recipients. CONCLUSIONS: A third dose of a SARS-CoV-2 mRNA vaccine is associated with high VE against symptomatic infection, hospitalization, and critical disease in the pre-Omicron era.

Initial anterior uveitis event associated with recent novel SARS-CoV-2 (COVID-19) infection in the setting of HLA-B27.

Purpose: To describe an atypical ocular manifestation following SARS-CoV-2 infection. Observations: A 27-year old previously healthy male with no past ocular history presented with pain, photophobia and red eye in his left eye (OS). His only notable mention on review of systems was a positive SARS-CoV-2 infection three weeks prior. Slit lamp examination demonstrated fine inferior keratic precipitates (KPs) in the inferior cornea and 3+ anterior chamber cells OS. There was no vitritis or chorioretinal lesions. The patient was diagnosed with his first event of acute anterior uveitis. Standard ocular inflammatory panel returned positive for HLA-B27. The postulated mechanism of initial anterior uveitis attack in the setting of COVID-19 infection was dysregulation of inflammatory cells and mediators in a patient with baseline elevated risk for ocular inflammation. Conclusions and Importance: It is crucial to investigate patients for HLA-B27 following initial anterior uveitis event if infected by SARS-CoV-2, as patients with HLA-B27 are at baseline higher risk of ocular inflammatory dysregulation.

In vivo antiviral effect of plant essential oils against avian infectious bronchitis virus.

BACKGROUND: Infectious bronchitis virus (IBV) leads to huge economic losses in the poultry industry worldwide. The high levels of mutations of IBV render vaccines partially protective. Therefore, it is urgent to explore an effective antiviral drug or agent. The present study aimed to investigate the in vivo anti-IBV activity of a mixture of plant essential oils (PEO) of cinnamaldehyde (CA) and glycerol monolaurate (GML), designated as Jin-Jing-Zi. RESULTS: The antiviral effects were evaluated by clinical signs, viral loads, immune organ indices, antibody levels, and cytokine levels. The infection rates in the PEO-M (middle dose) and PEO-H (high dose) groups were significantly lower than those in the prevention, positive drug, and PEO-L (low dose) groups. The cure rates in the PEO-M and PEO-H groups were significantly higher than those in the prevention, positive drug, and PEO-L groups, and the PEO-M group had the highest cure rate of 92.31%. The symptom scores and IBV mRNA expression levels were significantly reduced in the PEO-M group. PEO significantly improved the immune organ indices and IBV-specific antibody titers of infected chickens. The anti-inflammatory factor levels of IL-4 and IFN-γ in the PEO-M group maintained high concentrations for a long time. The IL-6 levels in the PEO-M group were lower than those in prevention, positive drug, and PEO-L groups. CONCLUSION: The PEO had remarkable inhibition against IBV and the PEO acts by inhibiting virus multiplication and promoting immune function, suggesting that the PEO has great potential as a novel anti-IBV agent for inhibiting IBV infection.

[Thumb-tack needles based on "Biaoben acupoint compatibility" for sequela of COVID-19 during recovery period].

OBJECTIVE: To observe the effect of thumb-tack needles based on "Biaoben acupoint compatibility" on sequela symptoms, mental state and pulmonary ventilation function in patients with coronavirus disease 2019 (COVID-19) during recovery period. METHODS: Fifty cases of COVID-19 during recovery period were randomly divided into an observation group and a control group, 25 cases in each group. The patients in the observation group were treated with thumb-tack needles at Guanyuan (CV 4), Zusanli (ST 36) and Taiyuan (LU 9). The patients in the control group were treated with sham thumb-tack needles at identical acupoints as the observation group. The treatment in the two groups was given once a day, 7-day treatment was taken as a course of treatment, and totally two courses of treatment were given. The TCM symptom score, Hamilton anxiety scale (HAMA) score, Hamilton depression scale (HAMD) score, pulmonary function (forced vital capacity [FVC], forced expiratory volume in the first second [FEV1], peak expiratory flow [PEF]), the severity of pulmonary ventilation dysfunction and pulmonary imaging changes in the two groups were compared before and after treatment. RESULTS: Compared before treatment, the total scores and each item scores of TCM symptom scale, HAMA scores and HAMD scores in the two groups were reduced after treatment (P<0.05). Except for the symptom scores of dry throat and dry stool, the total score and each item score of TCM symptom scale, HAMA score and HAMD score in the observation group were lower than those in the control group (P<0.05). Compared before treatment, FVC, FEV1 and PEF in the two groups were increased after treatment (P<0.05), and those in the observation group were higher than the control group (P<0.05). The severity of pulmonary ventilation dysfunction in the two groups was reduced after treatment (P<0.05), and the severity in the observation group was better than that in the control group (P<0.05). After treatment, the lung shadow area in the two groups was decreased (P<0.05), and that in the observation group was smaller than the control group (P<0.05). The improvement of imaging change in the observation group was better than that in the control group (P<0.05). CONCLUSION: The thumb-tack needles based on "Biaoben acupoint compatibility" could significantly reduce the sequela symptoms, anxiety and depression in patients with COVID-19 during recovery stage, and improve the pulmonary ventilation function.

A highly immunogenic live-attenuated vaccine candidate prevents SARS-CoV-2 infection and transmission in hamsters.

The highly pathogenic and readily transmissible SARS-CoV-2 has caused a global coronavirus pandemic, urgently requiring effective countermeasures against its rapid expansion. All available vaccine platforms are being used to generate safe and effective COVID-19 vaccines. Here, we generated a live-attenuated candidate vaccine strain by serial passaging of a SARS-CoV-2 clinical isolate in Vero cells. Deep sequencing revealed the dynamic adaptation of SARS-CoV-2 in Vero cells, resulting in a stable clone with a deletion of seven amino acids (N679SPRRAR685) at the S1/S2 junction of the S protein (named VAS5). VAS5 showed significant attenuation of replication in multiple human cell lines, human airway epithelium organoids, and hACE2 mice. Viral fitness competition assays demonstrated that VAS5 showed specific tropism to Vero cells but decreased fitness in human cells compared with the parental virus. More importantly, a single intranasal injection of VAS5 elicited a high level of neutralizing antibodies and prevented SARS-CoV-2 infection in mice as well as close-contact transmission in golden Syrian hamsters. Structural and biochemical analysis revealed a stable and locked prefusion conformation of the S trimer of VAS5, which most resembles SARS-CoV-2-3Q-2P, an advanced vaccine immunogen (NVAX-CoV2373). Further systematic antigenic profiling and immunogenicity validation confirmed that the VAS5 S trimer presents an enhanced antigenic mimic of the wild-type S trimer. Our results not only provide a potent live-attenuated vaccine candidate against COVID-19 but also clarify the molecular and structural basis for the highly attenuated and super immunogenic phenotype of VAS5.

Analysis of Continuous Mutation and Evolution on Circulating SARS-CoV-2

Monitoring the mutation and evolution of the virus is important for tracing its ongoing transmission and facilitating effective vaccine development. A total of 342 complete genomic sequences of SARS-CoV-2 were analyzed in this study. Compared to the reference genome reported in December 2019, 465 mutations were found, among which, 347 occurred in only 1 sequence, while 26 occurred in more than 5 sequences. For these 26 further identified as SNPs, 14 were closely linked and were grouped into 5 profiles. Phylogenetic analysis revealed the sequences formed 2 major groups. Most of the sequences in late period (March and April) constituted the Cluster II, while the sequences before March in this study and the reported S/L and A/B/C types in previous studies were all in Cluster I. The distributions of some mutations were specific geographically or temporally, the potential effect of which on the transmission and pathogenicity of SARS-CoV-2 deserves further evaluation and monitoring. Two mutations were found in the receptor-binding domain (RBD) but outside the receptor-binding motif (RBM), indicating that mutations may only have marginal biological effects but merit further attention. The observed novel sequence divergence is of great significance to the study of the transmission, pathogenicity, and development of an effective vaccine for SARS-CoV-2.

Human Umbilical Cord Mesenchymal Stem Cells Grown in 3D Micro-environment Ameliorate Acute Liver Injury by Immunoregulation and Proliferation Promotion (preprint)

Background Mesenchymal stem cells (MSCs) have been widely used for inflammatory diseases like acute liver injury (ALI) and COVID-19 diseases. However, most MSCs instead of the cell-matrix are cultured in 2 D plates, resulting in degeneration of some key functions along with a limited understanding of the immune response in tissue repairing. Herein, we obtained the human umbilical cord MSCs grown on microcarriers in 3 D suspension culture (3 D hUCMSCs) that proved more appreciative than 2 D hUCMSCs for the ALI therapy.Methods hUCMSCs were isolated and respectively cultured in 2 D plates and 3 D microcarriers in vitro, and acute liver injury model in mice was used to evaluate tissue repairing ability of the transplanted hUCMSCs. Nitric oxide production, cell proliferation and the relative protein expression level were comprehensively evaluated. Besides, the cytokine expression level in the of serum mice was detected by quantitative RT-PCR and cytokine antibody chip.Results When transplanted with 3 D hUCMSCs in ALI mice, the injured liver tissues have a significantly-increased histological scores and enhanced animal’s body/liver weight, superior to the 2 D hUCMSCs and control group. Pro-inflammatory cytokines (IL-6, IL-1β, IL-17, IL-22 and TNF-α), apoptosis promoter IFN-g, and NO production declined when transplanted with 3D hUCMSCs compared to the control group. Besides, anti-inflammatory cytokines (IL-10) was up-regulated.Conclusion Both the 3 D hUCMSCs and the conditioned medium were more favorable for the therapy of acute liver injury (ALI). Triple regulatory roles of the 3 D hUCMSCs include the effective promotion of M1/M2 macrophage switch through increased secreting of anti-inflammatory cytokines, ameliorating proliferation and NO downregulation of macrophage. A balance of these cytokines in the conditioned medium of 3 D hUCMSCs played a key role in ALI repairing. It was proven that the 3 D hUCMSCs could trigger the mitogen-activated protein kinases (MAPKs) and STAT3 signaling pathways. Conclusively, the revelation of the superior moderating effect of 3 D hUCMSCs and possible regulatory mechanisms will improve the clinical efficacy of stem cell therapy for inflammatory and immunological diseases.

Influencing factors and mechanism of doctor consultation volume on online medical consultation platforms based on physician review analysis

PurposeThis paper aims to reveal the factors patients consider when choosing a doctor for consultation on an online medical consultation (OMC) platform and how these factors influence doctors' consultation volumes.Design/methodology/approachIn Study 1, influencing factors reflected as service features were identified by applying a feature extraction method to physician reviews, and the importance of each feature was determined based on word frequencies and the PageRank algorithm. Sentiment analysis was used to analyze patient satisfaction with each service feature. In Study 2, regression models were used to analyze the relationships between the service features obtained from Study 1 and the doctor's consultation volume.FindingsThe study identified 14 service features of patients' concerns and found that patients mostly care about features such as trust, phraseology, overall service experience, word of mouth and personality traits, all of which describe a doctor's soft skills. These service features affect patients' trust in doctors, which, in turn, affects doctors' consultation volumes.Originality/valueThis research is important as it informs doctors about the features they should improve, to increase their consultation volume on OMC platforms. Furthermore, it not only enriches current trust-related research in the field of OMC, which has a certain reference significance for subsequent research on establishing trust in online doctor–patient relationships, but it also provides a reference for research concerning the antecedents of trust in general.