Immunoaffinity biosensors for the detection of SARS-CoV-1 using screened Fv-antibodies from an autodisplayed Fv-antibody library.

The detection of severe acute respiratory syndrome coronavirus (SARS-CoV-1) was demonstrated using screened Fv-antibodies for SPR biosensor and impedance spectrometry. The Fv-antibody library was first prepared on the outer membrane of E. coli using autodisplay technology and the Fv-variants (clones) with a specific affinity toward the SARS-CoV-1 spike protein (SP) were screened using magnetic beads immobilized with the SP. Upon screening the Fv-antibody library, two target Fv-variants (clones) with a specific binding affinity toward the SARS-CoV-1 SP were determined and the Fv-antibodies on two clones were named "Anti-SP1" (with CDR3 amino acid sequence: 1GRTTG5NDRPD11Y) and "Anti-SP2" (with CDR3 amino acid sequence: 1CLRQA5GTADD11V). The binding affinities of the two screened Fv-variants (clones) were analyzed using flow cytometry and the binding constants (KD) were estimated to be 80.5 ± 3.6 nM for Anti-SP1 and 45.6 ± 8.9 nM for Anti-SP2 (n = 3). In addition, the Fv-antibody including three CDR regions (CDR1, CDR2, and CDR3) and frame regions (FRs) between the CDR regions was expressed as a fusion protein (Mw. 40.6 kDa) with a green fluorescent protein (GFP) and the KD values of the expressed Fv-antibodies toward the SP estimated to be 15.3 ± 1.5 nM for Anti-SP1 (n = 3) and 16.3 ± 1.7 nM for Anti-SP2 (n = 3). Finally, the expressed Fv-antibodies screened against SARS-CoV-1 SP (Anti-SP1 and Anti-SP2) were applied for the detection of SARS-CoV-1. Consequently, the detection of SARS-CoV-1 was demonstrated to be feasible using the SPR biosensor and impedance spectrometry utilizing the immobilized Fv-antibodies against the SARS-CoV-1 SP.

Negative Conversion of Polymerase Chain Reaction and Clinical Outcomes according to the SARS-CoV-2 Variant in Critically Ill Patients with COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is an ongoing global public health threat and different variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been identified. This study aimed to analyse the factors associated with negative conversion of polymerase chain reaction (PCR) and prognosis in critically ill patients according to the SARS-CoV-2 variant. METHODS: This study retrospectively analysed 259 critically ill patients with COVID-19 who were admitted to the intensive care unit of a tertiary medical center between January 2020 and May 2022. The Charlson comorbidity index (CCI) was used to evaluate comorbidity, and a negative PCR test result within 2 weeks was used to define negative PCR conversion. The cases were divided into the following three variant groups, according to the documented variant of SARS-CoV-2 at the time of diagnosis: non-Delta (January 20, 2020-July 6, 2021), Delta (July 7, 2021- January 1, 2022), and Omicron (January 30, 2022-April 24, 2022). RESULTS: The mean age of the 259 patients was 67.1 years and 93 (35.9%) patients were female. Fifty (19.3%) patients were smokers, and 50 (19.3%) patients were vaccinated. The CCI (hazard ratio [HR], 1.555; p<0.001), vaccination (HR, 0.492; p=0.033), and Delta variant (HR, 2.469; p=0.002) were significant factors for in-hospital mortality. The Delta variant (odds ratio, 0.288; p=0.003) was associated with fewer negative PCR conversion; however, vaccination (p=0.163) and remdesivir (p=0.124) treatments did not. CONCLUSION: The Delta variant of SARS-CoV-2 is associated with lower survival and negative PCR conversion. Contrary to expectations, vaccination and remdesivir may not affect negative PCR conversion in critically ill patients with COVID-19.

A nationwide survey on the management of the COVID-19 pandemic and respiratory disease in South Korea.

Background: This study aimed to explore individual prevalence of respiratory symptoms and to describe the Korean population's treatment approaches, preventive health behaviors, and mental health conditions during the pandemic. Methods: We analyzed responses from an online nationwide survey, conducted between February 2021 to May 2021, about people's experiences during the pandemic. Statistical analysis was also performed to see if there were any significant differences in treatment and prevention strategies between different groups of respondents (between those had respiratory symptoms, compared with those who did not, and between those tested positive for COVID-19, compared with those who did not). Results: A total of 2,177 survey respondents completed the survey and, of these, only 142 had experienced symptoms. The most frequently reported respiratory infections related symptoms were runny or blocked nose (47.6%), cough (45.5%), fever (44.1%), sore throat (42.0%), and fatigue (30.1%). More than half of the respondents (53.1%) used complementary and alternative medicine (CAM) approaches as means of preventive measures. In terms of preventive behaviors, the more emphasized behaviors were mask-wearing (58.9%) and hand-washing after coming home (42.7%). The majority of the respondents (64.9%) did not show signs of mental health issues. Conclusion: In South Korea, conventional medicine was mainly used for COVID-19 treatment whereas CAM was commonly used as preventive measures. COVID-19 was also found to have less impact on the general population's mental health. The findings of this study may shed light on how the pandemic impacted the general population.

Herbal Medicines for Post-Acute Sequelae (Fatigue or Cognitive Dysfunction) of SARS-CoV-2 Infection: A Phase 2 Pilot Clinical Study Protocol.

Long-term sequelae refer to persistent symptoms or signs for >6 months after SARS-CoV-2 infection. The most common symptoms of sequelae are fatigue and neuropsychiatric symptoms (concentration difficulty, amnesia, cognitive dysfunction, anxiety, and depression). However, approved treatments have not been fully established. Herbal medicines are administered for 12 weeks to patients who continuously complain of fatigue or cognitive dysfunction for >4 weeks that only occurred after COVID-19 diagnoses. Based on the Korean Medicine syndrome differentiation diagnosis, patients with fatigue will be administered Bojungikgi-tang or Kyungok-go, whereas those with cognitive dysfunction will be administered Cheonwangbosim-dan. Results could support evidence that herbal medicines may mitigate fatigue and cognitive dysfunction caused by COVID-19. Furthermore, by investigating the effects of herbal medicines on changes in metabolite and immune response due to COVID-19, which may be responsible for sequelae, the potential of herbal medicines as one of the therapeutic interventions for post-acute sequelae of SARS-CoV-2 infection can be evaluated. Therefore, the effects of herbal medicine on fatigue and cognitive dysfunction sequelae due to COVID-19 will be elucidated in this study to provide an insight into the preparation of medical management for the post-acute sequelae of SARS-CoV-2 infection.

Complementary and Alternative Medicine for Long COVID: Scoping Review and Bibliometric Analysis.

Prolonged symptoms after the clearance of acute coronavirus disease 2019 (COVID-19) infection, termed long COVID, are an emerging threat to the post-COVID-19 era. Complementary and alternative medicine (CAM) interventions may play a significant role in the management of long COVID. The present study aimed to identify published studies on the use of CAM interventions for long COVID and provide an overview of the research status using bibliometric analysis. The present scoping review searched MEDLINE, Embase, and Cochrane Library from inception until November 2021 and identified published studies on CAM interventions for long COVID. A narrative analysis of the study types and effectiveness and safety of the CAM interventions are presented and a bibliometric analysis of citation information and references of the included publications were analyzed using the Bibliometrix package for R. An electronic database search identified 16 publications (2 clinical studies and 14 study protocols of systematic reviews or clinical studies) that were included in the present study. Dyspnea or pulmonary dysfunction, quality of life, olfactory dysfunction, and psychological symptoms after COVID-19 infection were assessed in the included publications. The two clinical studies suggested that Chinese herbal medications were effective in relieving symptoms of pulmonary dysfunction. Bibliometric analysis revealed the current trend of research publication in this area was driven by study protocols written by Chinese, Korean, and Indian authors. Thus, the present scoping review and bibliometric analysis revealed that there are few studies published about the use of CAM for long COVID and long-term management for COVID-19 survivors. Original studies on CAM interventions, including randomized controlled trials and systematic reviews, are required to actively support evidence for their use in the management of long COVID. PROSPERO registration: this trial is registered with CRD42021281526.

Use of Traditional, Complementary and Integrative Medicine During the COVID-19 Pandemic: A Systematic Review and Meta-Analysis.

Background: Traditional, Complementary and Integrative Medicine (TCIM) has been reported to use for symptom management of coronavirus disease 2019 (COVID-19). The objective of this review was to identify the overall usage prevalence of TCIM interventions for COVID-19. Methods: Surveys on the general population and observational studies on the COVID-19 patient chart review were located in the search of PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases in September 2021. Observational studies, such as cross-sectional studies, surveys, cohort studies and hospital-based patient case reviews, published in any language, reporting the usage of TCIM in the patients with COVID-19 or the general population during the COVID-19 pandemic were included in this review. Data screening and extraction were performed independently by two reviewers. The reporting quality of the included studies was assessed with the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement. To conduct a meta-analysis of the usage prevalence of various TCIM interventions, the effect size of the proportion for each intervention was calculated with the inverse variance method. The main outcome was usage prevalence of TCIM interventions among patients with COVID-19 or the general population during the COVID-19 pandemic. Results: A total of 62 studies were included in this review. The overall TCIM usage prevalence was estimated to be 0.64 (95% CI 0.54-0.73). The overall prevalence did not differ between the population-based survey (0.65, 95% CI 0.48-0.81) and the hospital-based patient case review (0.63, 95% CI 0.52-0.73). Statistical heterogeneity and comparatively low quality in reporting were observed, which should be cautiously considered when interpreting the results. Conclusion: Various TCIM interventions were reported to be used with comparatively high frequency. Future international collaborative research might overcome the main limitation of this study, i.e., the heterogeneity of the included data. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=278452, identifier: CRD42021278452.

Complementary and alternative medicine (CAM) interventions for COVID-19: An overview of systematic reviews.

Background: Since the beginning of the Coronavirus disease 2019 (COVID-19) pandemic, various complementary and alternative medicines (CAMs) have been used in clinical practice. In this overview, we summarized the evidence for CAM interventions in the treatment of COVID-19 patients. Methods: For this overview, PubMed, Embase and Cochrane Library were searched from inception to October 2021. Systematic reviews (SRs) on the effectiveness and safety of CAM interventions for COVID-19 patients were located, and the MeaSurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) was used to evaluate the reporting quality of the included SRs. Keywords including COVID-19 and CAM interventions were used for locating SRs. For evidence mapping, we created a two-dimensional bubble plot that included the width and strength of the evidence for each CAM intervention and specific outcome. Results: In this overview, we identified 24 SRs (21 for Traditional Chinese Medicine (TCM) medications, two for vitamin D and one for home-based activity). From the included SRs, TCM herbal medications were reported to show good results in decreasing the rate of disease progression (relative risk (RR) 0.30, 95% confidence intervals (CI) [0.20, 0.44]), time to the resolution of fever (standard mean difference (SMD) -0.98, 95% CI [-1.78, -0.17]) and rate of progression to severe COVID-19 cases (RR 0.34, 95% CI [0.18, 0.65]), but the evidence for other interventions did not show effectiveness with certainty. Gastric disturbance was a major adverse event of TCM medications. Conclusion: There is evidence that TCM medications are effective in the symptom management of COVID-19 patients. However, evidence for the effectiveness of most CAM interventions still needs evaluation.

Isolation of Antibodies Against the Spike Protein of SARS-CoV from Pig Serum for Competitive Immunoassay.

Several endemic corona viruses (eCoVs) have been reported to be the most common etiologic agents for the seasonal common cold and also cause pneumonia. These eCoVs share extensive sequence homology with SARS-CoV-2, and immune responses to eCoVs can cross-react with SARS-CoV-2 antigens. Based on such cross-reactivity of antigens among eCoVs, the IgG antibodies against the spike protein (SP) of severe acute respiratory syndrome coronavirus (SARS-CoV) were isolated from pig serum using magnetic beads immobilized with SARS-CoV SP and a protein-A column. The selectivity of the isolated antibodies was tested using different types of antigens, such as SARS-CoV-2 nucleoprotein (NP), influenza A virus (Beijing type), influenza B virus (Tokio and Florida types), human hepatitis B virus surface antigen (HBsAg), and bovine serum albumin (BSA). From the selectivity test, the anti-SP antibodies isolated from pig serum had sufficient selectivity to other kinds of viral antigens, and the apparent binding constant of the isolated antibodies was approximately 1.5 × 10-8 M from the surface plasmon resonance (SPR) measurements. Finally, the isolated anti-SP antibodies were applied to the immunoassay of SP using competitive immunoassay configuration. The feasibility of the detection as well as the quantitative analysis of the SARS-CoV viral culture fluid was determined using four viral culture samples, namely, SARS-CoV, SARS-CoV-2, MERS-CoV, and CoV-229E.

Competitive Immunoassay of SARS-CoV-2 Using Pig Sera-Derived Anti-SARS-CoV-2 Antibodies.

Anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) nucleoprotein (NP) antibodies were isolated from pig sera using human SARS-CoV-2 NP-immobilized magnetic beads. The binding properties of the isolated antibodies against SARS-CoV-2 NP were tested via flow cytometry using SARS-CoV-2 NP-immobilized magnetic beads. A competitive immunoassay was developed for detecting SARS-CoV-2 NP as well as SARS-CoV-2 in the culture fluid using magnetic beads with immobilized anti-SARS-CoV-2 NP antibodies. Selectivity tests were carried out during the competitive immunoassay for SARS-CoV, MERS-CoV, and CoV strain 229E in the culture fluid.

Pig Sera-derived Anti-SARS-CoV-2 Antibodies in Surface Plasmon Resonance Biosensors.

Anti-coronavirusdisease-2019 (COVID-19; anti-severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2)) antibodies against nucleoprotein (NP) were purified from pig sera. Following the separation of the antibody fraction using a protein-A column, the final yield of the purified antibodies against SARS-CoV-2 NPs was estimated to be 0.26 ± 0.05 % (absolute amount of 143.4 ± 25.2 ng, n=5) from 1 mL of pig sera. The binding activities of the isolated antibodies were confirmed using immunoassay and immunostaining. Based on the specific binding activity to NPs, a quantitative assay was performed using a surface plasmon resonance (SPR) biosensor. From the doseresponse curve, the binding constant (Kd) was calculated to be 185 pM and the limit of detection was estimated to be 1.02 pM. The SPR biosensor with the isolated antibodies against SARS-CoV-2 NPs was applied for the detection of SARS-CoV-2, MERS-CoV, and CoV strain 229E in culture fluid.