LSR is a cell-intrinsic defence factor against SARS-CoV-2 infection in small intestine (preprint)

The identification of host factors with antiviral potential is important for developing effective prevention as well as therapeutic strategies against SARS-CoV-2. Here, we have identified the lipolysis-stimulated lipoprotein receptor (LSR) as a crucial host-defense factor against SARS-CoV-2 infection in small intestine using immortalized cell lines, intestinal organoids, ex vivo intestinal tissues, and humanized ACE2 mouse model as proof-of-principle systems. Loss of endogenous LSR enhances ACE2-dependent infection by pseudotyped virus and authentic SARS-CoV-2 virus, and exogenous administration of LSR protect against viral infection. Mechanistically, LSR interacts with ACE2 both in cis and in trans, preventing its binding to Spike protein, and thus blocking viral entry and restricting Spike-mediated cell-cell fusion. These results identify both a previously unknown function for LSR and an associated antiviral host defense mechanism against SARS-CoV-2. The capacity of a small LSR-derived peptide to block Spike binding to the ACE2 receptor holds promise for pan-variant therapeutic interventions.

Single-shot AAV-vectored vaccine against SARS-CoV-2 with fast and long-lasting immunity.

Due to the insufficient long-term protection and significant efficacy reduction to new variants of current COVID-19 vaccines, the epidemic prevention and control are still challenging. Here, we employ a capsid and antigen structure engineering (CASE) strategy to manufacture an adeno-associated viral serotype 6-based vaccine (S663V-RBD), which expresses trimeric receptor binding domain (RBD) of spike protein fused with a biological adjuvant RS09. Impressively, the engineered S663V-RBD could rapidly induce a satisfactory RBD-specific IgG titer within 2 weeks and maintain the titer for more than 4 months. Compared to the licensed BBIBP-CorV (Sinopharm, China), a single-dose S663V-RBD induced more endurable and robust immune responses in mice and elicited superior neutralizing antibodies against three typical SARS-CoV-2 pseudoviruses including wild type, C.37 (Lambda) and B.1.617.2 (Delta). More interestingly, the intramuscular injection of S663V-RBD could overcome pre-existing immunity against the capsid. Given its effectiveness, the CASE-based S663V-RBD may provide a new solution for the current and next pandemic.

Longitudinal wastewater surveillance addressed public health priorities during the transition from "dynamic COVID-zero" to "opening up" in China: a population-based study (preprint)

Background Wastewater surveillance provides real-time, cost-effective monitoring of SARS-CoV-2 transmission. We developed the first city-level wastewater warning system in mainland China, located in Shenzhen. Our study aimed to reveal cryptic transmissions under the "dynamic COVID-zero" policy and characterize the dynamics of the infected population and variant prevalence, and then guide the allocation of medical resources during the transition to "opening up" in China. Methods In this population-based study, a total of 1,204 COVID-19 cases were enrolled to evaluate the contribution of Omicron variant-specific faecal shedding rates in wastewater. After that, wastewater samples from up to 334 sites distributed in communities and port areas in two districts of Shenzhen covering 1.74 million people were tested daily to evaluate the sensitivity and specificity of this approach and were validated against daily SARS-CoV-2 screening. After the public health policy was switched to "opening up" in December 7, 2022, we conducted wastewater surveillance at wastewater treatment plants and pump stations covering 3.55 million people to estimate infected populations using model prediction and detect the relative abundance of SARS-CoV-2 lineages using wastewater sequencing. Findings In total, 82.4% of SARS-CoV-2 Omicron cases tested positive for faecal viral RNA within the first four days after the diagnosis, which was far more than the proportion of the ancestral variant. A total of 27,759 wastewater samples were detected from July 26 to November 30 in 2022, showing a sensitivity of 73.8% and a specificity of 99.8%. We further found that wastewater surveillance played roles in providing early warnings and revealing cryptic transmissions in two communities. Based on the above results, we employed a prediction model to monitor the daily number of infected individuals in Shenzhen during the transition to "opening up" in China, with over 80% of the population infected in both Futian District and Nanshan District. Notably, the prediction of the daily number of hospital admission was consistent with the actual number. Further sequencing revealed that the Omicron subvariant BA.5.2.48 accounted for the most abundant SARS-CoV-2 RNA in wastewater, and BF.7.14 and BA.5.2.49 ranked second and third, respectively, which was consistent with the clinical sequencing. Interpretation This study provides a scalable solution for wastewater surveillance of SARS-CoV-2 to provide real-time monitoring of the new variants, infected populations and facilitate the precise prediction of hospital admission. This novel framework could be a One Health system for the surveillance of other infectious and emerging pathogens with faecal shedding and antibiotic resistance genes in the future. Funding Sanming Project of Medicine in Shenzhen, Shenzhen Key Medical Discipline Construction Fund.

A Decision Support Framework for Curriculum Planning in Undergraduate Supply Chain Management Program: An Integrated Approach

Curriculum planning is an important but complex and challenging decision-making problem at universities. There is a growing interest in curriculum planning problem. However, the body of research on curriculum planning process using analytical methods is still small. Additionally, prior research focused on planning of an individual curriculum or making study plan for students. Curriculum planning at the program level is an under-researched topic. A robust model has not been constructed to address curriculum selection and credit allocation problems simultaneously. To help educational leaders make the most appropriate curriculum plan corresponding to their goals with the highest level of utility achieved, this study presents a new decision support framework with integrated approach. In the proposed framework, based on the competency weights derived from the analytical hierarchy process method, the importance of each potential curriculum is evaluated using the fuzzy comprehensive evaluation method. An exploratory estimation is made to calculate the contribution values of competency development by each curriculum taught at different levels. Finally, multichoice goal programming with utility function determines the curriculum to be provided and corresponding credits to minimize the aggregate deviations from predefined goals with multiple aspirations. An application to curriculum planning of an undergraduate supply chain management program is presented to validate the flexibility and practicality of the proposed approach. The implications of the study are not restricted to curriculum planning of supply chain management program.

Does the COVID-19 pandemic derail US-China collaboration on carbon neutrality research? A survey

The COVID-19 pandemic has seriously impacted scientific research activities, especially international cooperation in scientific research. Using bibliometric methods and scientific knowledge graph software, and by calculating collaboration indicators such as international collaboration rates, this work conducts a comprehensive review of carbon neutrality publications in the Web of Science database before and during the COVID-19 pandemic, aiming to explore whether the COVID-19 pandemic derail China-U.S. collaboration on carbon neutrality research. The results show that (i) During the COVID-19 pandemic, more extensive research on carbon neutrality was carried out around the world, with China and the United States leading the way in carbon neutrality scientific output. (ii) Following the outbreak of the COVID-19, the global center of global carbon neutrality shifted from the United States to China. (iii) During the COVID-19 pandemic, research ties between China and the United States strengthened. The number of joint publications on carbon neutrality between China and the United States has greatly increased during the COVID-19 pandemic compared to those before. (iv) The proportion of China-U.S. cooperation in China's international cooperation has decreased, while it is the opposite for the United States. At the end of the article, we put forward relevant suggestions for realizing the sustainable development goals of climate change in the post-epidemic era for policymakers' reference. This paper provides offers important insights into the theoretical research of scholars in the field of carbon neutrality.

Single-shot AAV-vectored vaccine against SARS-CoV-2 with fast and long-lasting immunity☆

Due to the insufficient long-term protection and significant efficacy reduction to new variants of current COVID-19 vaccines, the epidemic prevention and control are still challenging. Here, we employ a capsid and antigen structure engineering (CASE) strategy to manufacture an adeno-associated viral serotype 6-based vaccine (S663V-RBD), which expresses trimeric receptor binding domain (RBD) of spike protein fused with a biological adjuvant RS09. Impressively, the engineered S663V-RBD could rapidly induce a satisfactory RBD-specific IgG titer within 2 weeks and maintain the titer for more than 4 months. Compared to the licensed BBIBP-CorV (Sinopharm, China), a single-dose S663V-RBD induced more endurable and robust immune responses in mice and elicited superior neutralizing antibodies against three typical SARS-CoV-2 pseudoviruses including wild type, C.37 (Lambda) and B.1.617.2 (Delta). More interestingly, the intramuscular injection of S663V-RBD could overcome pre-existing immunity against the capsid. Given its effectiveness, the CASE-based S663V-RBD may provide a new solution for the current and next pandemic. Graphical By engineering capsid of AAV vector and designing a sequence encoding trimeric RBD fused with a biological adjuvant, AAV-based vaccines successfully induce fast, balanced and endurable humoral and cellular immune responses, thus serving as potential candidates for next generation vaccinesImage 1

Analysis of differences in lymphocyte subsets and CD4+ T cells immune activation between re-detectable positive and non-re-detectable positive COVID-19 convalescent patients (preprint)

Background: Recently many literature were reported on the re-detectable positive phenomenon of COVID-19 patients during recovery, but there were few studies on the lymphocyte subsets and T-lymphocyte activation indicators between the RP (re-detectable positive) and NRP (non-re-detectable positive) patients. The aim of this study was to analyze immunological characteristics of RP and NRP patients among convalescent patients from post-discharge COVID-19 patients. Methods: Anticoagulated whole blood samples were collected from 11HCs (healthy controls) and 66 COVID-19 convalescent patients, then the percentage of lymphocyte subsets and CD4+CD38+/HLA-DR+ T cells were tested with flow cytometry, SARS-CoV-2 S RBD-IgG antibody ( anti-spike protein receptor-binding domain IgG antibody) was detected by chemiluminescence. Results: B cells (%) in RP group was significantly lower than that in HC group (P=0.005), and B cells (%) decreased successively in HC, NRP and RP group, with significant differences among the three groups (P=0.016). CD3+ and CD8+T cells (%) in RP group were noticeably higher than that in NRP group (P=0.004,0.019, respectively), but there was no difference in CD4+T cells (%) and NK cells (%) among the three groups. The CD4+CD38+ and CD4+HLA-DR+T cells (%) in RP group were noticeably higher than that in HC group (P=0.025,0.018). ANOVA (Analysis of variance) of the three groups showed that CD4+CD38+ and HLA-DR+T cells (%) were also significant difference (P=0.037, 0.029), and CD4+HLA-DR+T cells (%) in the three groups increased in turn. Meanwhile, there was a substantial positive correlation between RBD-IgG titer and CD4+HLA-DR+(%) (P=0.003, r=0.517), and the RBD-IgG titer of HLA-DR + high group was obviously higher than that of HLA-DR + Low group (P=0.005). Conclusions: In this work, we analyzed the immunological characteristics of re-detectable positive COVID-19 convalescent patients through lymphocyte subsets, suggesting that the low B cells (%) and the increased CD4+HLA-DR+T cells (%) in the convalescent patients of COVID-19 may be related to re-detectable positive phenomenon. 

Rapid evaluation of neutralizing antibodies in COVID-19 patients (preprint)

The ongoing coronavirus disease 2019 (COVID-19) pandemic calls for a method to rapidly and conveniently evaluate neutralizing antibody (NAb) activity in patients. Here, an up-conversion phosphor technology-based point-of-care testing (UPT-POCT) and a microneutralization assay were employed to detect total antibodies against the receptor-binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and NAb activity in COVID-19 patients' sera, respectively, in order to determine if UPT-POCT could be used as a surrogate method for rapid evaluation of serum NAb activity in COVID-19 patients. In total, 519 serum samples from 213 recovered and 99 polymerase chain reaction re-positive (RP) COVID-19 patients were used in this report. We found that UPT-POCT reporting values correlated highly with NAb titers from 1:4 to 1:1024, with a correlation coefficient r = 0.9654 (P < 0.001), as well as protection rate against RP (r = 0.9886, P < 0.0001). As a significant point for reducing re-positive rate, UPT-POCT values of 4.380, corresponding to NAb titer of 1:64, may be appropriate as an indicator for evaluating high efficiency of protection. This study demonstrates that the quantitative lateral flow based UPT-POCT, could be used to rapidly evaluate NAb titer, which is of importance for assessing vaccine immunization efficacy, herd immunity, and screening patient plasma for high NAbs.

Viral RNA level, serum antibody responses, and transmission risk in discharged COVID-19 patients with recurrent positive SARS-CoV-2 RNA test results: a population-based observational cohort study (preprint)

SummaryO_ST_ABSBackgroundC_ST_ABSManaging discharged COVID-19 (DC) patients with recurrent positive (RP) SARS-CoV-2 RNA test results is challenging. We aimed to comprehensively characterize the viral RNA level and serum antibody responses in RP-DC patients and evaluate their viral transmission risk. MethodsA population-based observational cohort study was performed on 479 DC patients discharged from February 1 to May 5, 2020 in Shenzhen, China. We conducted RT-qPCR, antibody assays, neutralisation assays, virus isolation, whole genome sequencing (WGS), and epidemiological investigation of close contacts. FindingsOf 479 DC patients, the 93 (19%) RP individuals, including 36 with multiple RP results, were characterised by young age (median age: 34 years, 95% confidence interval [CI]: 29-38 years). The median discharge-to-RP length was 8 days (95% CI: 7-14 days; maximum: 90 days). After readmission, RP-DC patients exhibited mild (28%) or absent (72%) symptoms, with no disease progression. The viral RNA level in RP-DC patients ranged from 1{middle dot}9-5{middle dot}7 log10 copies/mL (median: 3{middle dot}2, 95% CI: 3{middle dot}1-3{middle dot}5). At RP detection, the IgM, IgG, IgA, total antibody, and neutralising antibody (NAb) seropositivity rates in RP-DC patients were 38% (18/48), 98% (47/48), 63% (30/48), 100% (48/48), and 91% (39/43), respectively. Regarding antibody levels, there was no significant difference between RP-DC and non-RP-DC patients. The antibody level remained constant in RP-DC patients pre- and post-RP detection. Virus isolation of nine representative specimens returned negative results. WGS of six specimens yielded only genomic fragments. No clinical symptoms were exhibited by 96 close contacts of 23 RP-DC patients; their viral RNA (96/96) and antibody (20/20) test results were negative. After full recovery, 60% of patients (n=162, 78 no longer RP RP-DC and 84 non-RP-DC) had NAb titres of [≥]1:32. InterpretationRP may occur in DC patients following intermittent and non-stable excretion of low viral RNA levels. RP-DC patients pose a low risk of transmitting SARS-CoV-2. An NAb titre of [≥] 1:32 may provide a reference indicator for evaluating humoral responses in COVID-19 vaccine clinical trials. FundingSanming Project of Medicine in Shenzhen, China National Science and Technology Major Projects Foundation, Special Foundation of Science and Technology Innovation Strategy of Guangdong Province of China, and Shenzhen Committee of Scientific and Technical Innovation grants.

Comparative Evaluation of Six Molecular Assays based on RT-PCR and Cross Primer Isothermal Amplification for SARS-CoV-2 RNA Detection (preprint)

Background: SARS-CoV-2 is a newly emerged coronavirus, causing the coronavirus disease 2019 (COVID-19) outbreak in December, 2019. As drugs and vaccines of COVID-19 remain in development, accurate virus detection plays a crucial role in the current public health crisis. Quantitative real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) kits have been reliably used for detection of SARS-CoV-2 RNA since the beginning of the COVID-19 outbreak, whereas isothermal nucleic acid amplification-based point-of-care automated kits have also been considered as a simpler and rapid alternative. However, as these kits have only been developed and applied clinically within a short timeframe, their clinical performance has not been adequately evaluated to date. We describe a comparative study between a newly developed cross-priming isothermal amplification (CPA) kit (Kit A) and five RT-qPCR kits (Kits B–F) to evaluate their sensitivity, specificity, predictive values and accuracy. Methods: Fifty-two clinical samples were used including throat swabs (n=30), nasal swabs (n=7), nasopharyngeal swabs (n=7) and sputum specimens (n=8), comprising confirmed (n=26) and negative cases (n=26). SARS-CoV-2 detection was simultaneously performed on each sample using six nucleic acid amplification kits. The sensitivity, specificity, positive/negative predictive values (PPV/NPV) and the accuracy for each kit were assessed using clinical manifestation and molecular diagnoses as the reference standard. Reproducibility for RT-qPCR kits was evaluated in triplicate by three different operators using a SARS-CoV-2 RNA-positive sample. On the basis of the six kits’ evaluation results, CPA kit (Kit A) and two RT-qPCR Kits (Kit B and F) were applied to the SARS-CoV-2 detection in close-contacts of COVID-19 patients. Results: For Kit A, the sensitivity, specificity, PPV/NPV and accuracy were 100%. Among the five RT-qPCR kits, Kits B, C and F had good agreement with the clinical diagnostic reports (Kappa≥0.75); Kits D and E were less congruent (0.4≤Kappa<0.75). Differences between all kits were statistically significant (P<0.001). The reproducibility of RT-qPCR kits was determined using a coefficients of variation (CV) between 0.95% and 2.57%, indicating good reproducibility. Conclusions: This is the first comparative study to evaluate CPA and RT-qPCR kits’ specificity and sensitivity for SARS-CoV-2 detection, and could serve as a reference for clinical laboratories, thus informing testing protocols amid the rapidly progressing COVID-19 pandemic. Keywords: SARS-CoV-2; COVID-19; nucleic acid detection; real-time reverse transcriptase PCR (RT-qPCR); cross-priming isothermal amplification (CPA)

SARS-COV-2 RBD Oral Vaccine Boosted by Mucosal Immune Adjuvant LTB26 via DCs and B Cells Activation in Mice (preprint)

Although several SARS-COV-2 vaccines have been approved, no one oral live vaccine is available. Here, an oral SARS-COV-2 RBD live vaccine containing LTB26 adjuvant has been developed. BALB/c mice are oral vaccinated with attenuated Salmonella typhimurium SL7207 containing pcDNA3.1-LTB26RBD or pcDNA3.1-RBD plasmids. The result shows that the high level of RBD specific antibody is produced in pcDNA3.1- LTB26RBD treatment. The mechanism indicates that LTB26 enhances RBD antibody production by significantly upregulating the activity of MHC II + DCs and CD19 + CD45 + B cells. LTB26 mutant is derived from heat-labile enterotoxin B subunit (LTB) wild type of Escherichia coli with enhanced immune adjuvanticity. Based on the pre-experiment result that SL7207 interferes the function of LTB26, the purified LTB26 was mixed with purified human rotavirus VP8 antigen to explore the mechanism of adjuvant. The results suggests that LTB26 enhances mucosal immune responses via increased of BCR and MHC II + expression. Furthermore, LTB26 promotes both Th1 and Th2 cell mediated immunity. Therefore, LTB26 maybe a potent adjuvant for mucosal vaccine development in view of the safety of LTB26 than LT toxin.