Wearable Aiegens-Based Lateral Flow Test Strip for Rapid Detection of SARS-CoV-2 N Protein and BRD Protein (preprint)

\Accurate and rapid detection of SARS-CoV-2 is significant for early tracing, isolating and treating the infected patients, which will efficiently prevent the virus large-scale spread from human to human. In this paper, two kinds of novel quantitative lateral flow test strip for N and RBD antigens of SARS-CoV-2 were established with high sensitivity, which utilize AIE luminogens (AIEgens) as reporter. Because of the high brightness and resistance of quenching property in aqueous of the AIEgens, the limit of detection of 7.2 ng/mL for N protein and 6.9 ng/mL for RBD protein could be achieved with the AIEgens-based lateral flow test strip. Furthermore, it was negative for other protein or antigen samples assay, which demonstrated the great specificity of the test strategy. A N95 mask equipped with the test strip was designed to employ as the antigen collector with excellent enrichment effect. Compared with the other two test strips based on the Au nanoparticle and FITC, the well-designed AIEgens-based lateral flow test strip presented high sensitivity and excellent anti-interference capacity in complex bio-samples. Furthermore, the AIEgens-based lateral flow test strip assay could be built as a promising platform for the emergency usage at pandemic.Funding: This work was supported by the NSFC (51961160730, 51873092, and 81921004), the National Key R&D Program of China (Intergovernmental Cooperation Project, 2017YFE0132200), the Fundamental Research Funds for the Central Universities, and the Tianjin Science Fund for Distinguished Young Scholars (19JCJQJC61200).Declaration of Interests: The authors declare no competing interests.

Establishment and Functioning of a Temporary 1000-Bed COVID-19 Hospital During the Initial Outbreak in Wuhan (preprint)

Background: COVID-19 Emerged as a novel zoonotic disease in late 2019 and quickly spread across Wuhan before spreading to other parts of China and rest of the world. Due to the rapid spread of the disease, local hospitals were inundated with COVID-19 patients putting a strain on the healthcare system. Little was known about the transmission and potential clinical management of COVID-19 at that time.Methods: A temporary COVID-19 hospital was built within one week. The confirmed COVID-19 cases were either directly recruited to the hospital or were transferred from other hospitals. Patients were admitted for both quarantine and treatment, as required. Data were collected as part of standard clinical care and retrospectively analyzed.Findings: A total of 2,959 patients were recruited during the operation period of this hospital between February 4, 2020, and April 8, 2020. These patients included 838 severe patients of which 72 were classified as critical, and 66 patients died. No infection was reported among healthcare workers.Interpretation: Setting up a dedicated hospital for COVID-19 provided a critical resource during the peak of the pandemic in Wuhan by enabling both quarantine and treatment for the infected patients. The mortality in this hospital was comparable to other hospitals at the time. These data suggest that this approach may prove beneficial in controlling infectious disease spread and limit mortality and prevent strain on existing healthcare system to enable them to care for non-COVID-19 patients.Funding Statement: This study was supported by funding from Beijing Nova Program Interdisciplinary Cooperation Project (DC; No. Z191100001119021), Chinese PLA General Hospital Youth Project (DC; No.QNF19074), Beijing Nova Program Project (DC; No. Z171100001117012), and China 13th Five-year National Key Grant (LXX; No.2018ZX09201013).Declaration of Interests: The authors declare that there are no competing interests.Ethics Approval Statement: This study was approved by the ethics committee of the Chinese PLA General Hospital, with a waiver of informed consent.

Long-term Existence of SARS-CoV-2 in COVID-19 Patients: Host Immunity, Viral Virulence, and Transmissibility (preprint)

COVID-19 patients can recover with a median SARS-CoV-2 clearance of 20 days post initial symptoms (PIS). However, we observed some COVID-19 patients with existing SARS-CoV-2 for more than 50 days PIS. This study aimed to investigate the cause of viral clearance delay and the infectivity in these patients. Demographic data and clinical characteristics of 22 long-term COVID-19 patients were collected. SARS-CoV-2 nucleic acid, peripheral lymphocyte count, and functionality were assessed. SARS-CoV-2-specific and neutralization antibodies were detected, followed by virus isolation and genome sequencing. The median age of the studied cohort was 59.83±12.94 years. All patients were clinically cured after long-term SARS-CoV-2 infection ranging from 53 to 112 days PIS. Peripheral lymphocytes counts were normal. Interferon gamma (IFN-ƴ)-generated CD4+ and CD8+ cells were normal as 24.68±9.60% and 66.41±14.87%. However, the number of IFN-ƴ-generated NK cells diminished (58.03±11.78%). All patients presented detectable IgG, which positively correlated with mild neutralizing activity (ID50=157.2, P=0.05). SARS-CoV-2 was not isolated, and a cytopathic effect was lacking. Only three synonymous variants were identified in spike protein coding regions. In conclusion, decreased IFN-γ production by NK cells and low neutralizing antibodies might favor SARS-CoV-2 long-term existence. Further, low viral load and weak viral pathogenicity was observed in COVID-19 patients with long-term SARS-CoV-2 infection.

Heat inactivation of serum interferes with the immunoanalysis of antibodies to SARS-CoV-2 (preprint)

The detection of serum antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging as a new tool for the coronavirus disease-2019 (COVID-19) diagnosis. Since many coronaviruses are sensitive to heat, heating inactivation of samples at 56 prior to testing is considered a possible method to reduce the risk of transmission, but the effect of heating on the measurement of SARS-CoV-2 antibodies is still unclear. By comparing the levels of SARS-CoV-2 antibodies before and after heat inactivation of serum at 56 for 30 minutes using a quantitative fluorescence immunochromatographic assay, we shown that heat inactivation significantly interferes with the levels of antibodies to SARS-CoV-2. The IgM levels of all the 34 serum samples (100%) from COVID-19 patients decreased by an average level of 53.56%. The IgG levels were decreased in 22 of 34 samples (64.71%) by an average level of 49.54%. Similar changes can also be observed in the non-COVID-19 diseases group (n=9). Of note, 44.12% of the detected IgM levels were dropped below the cut-off value after heating, suggesting heat inactivation can lead to false-negative results of these samples. Our results indicate that heat inactivation of serum at 56 for 30 minutes interferes with the immunoanalysis of antibodies to SARS-CoV-2. Heat inactivation prior to immunoanalysis is not recommended and the possibility of false-negative results should be considered if the sample was pre-inactivated by heating.

Clinical course and progression of severe and critically ill patients with corona virus disease 2019 (preprint)

Background：The emergence of Corona Virus Disease 2019 (COVID-19) in Wuhan, China at the end of 2019 is a major public health issue, causing to a large global outbreak. However, the information regarding the clinical characteristic and progression of severe and critically ill patients with COVID-19 is scarce.Methods: We conducted a single-center, retrospective, observational study and enrolled 126 severe and critically ill adult patients who were admitted to the intensive care unit (ICU) of Tongji hospital, between Feb 1 and Feb 20, 2020.Results: Of 126 patients, 85 patients with the positive of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were included. The mean age of 85 patients was 68.3 (SD 10.5) years. More than half were men, 55 (62.4%) had chronic illness. 57 (66.3%) patients had died before Feb 28, 2020. the median duration from onset of illness to death, hospitalization to death and ICU admission to death were 22 (17.0-26.0) days, 9.0 (6.0-13.0) days and 5.0 (2.0-6.0) days, respectively. Compared with survivors, non-survivors were more likely old (69.6 [SD 10.22] vs 65.6 [10.9]). Furthermore, the non-survivors had higher white blood cell (WBC) and neutrophil count, neutrophil percentage, high-sensitive C-reactive protein (hs-CRP) and lower lymphocyte and platelet count, lymphocyte percentage and albumin. Notably, arbidol may improve the survival of severe and critically ill patients.Conclusions: Our study reveals the non-survivors had worse blood routine and other clinical monitors. Additionally, arbidol may play useful role in the survival of severe and critically ill patients, which needs further validation.