Multi-scenario surveillance of respiratory viruses in aerosols with a sub-single molecule spatial resolution (preprint)

Highly sensitive airborne virus monitoring is critical for preventing and containing epidemics. However, the detection of airborne viruses at ultra-low concentrations remains challenging due to the lack of ultra-sensitive methods and easy-to-deployment equipment. Here, we present an integrated microfluidic cartridge that can accurately detect SARS-CoV-2 and various respiratory viruses with a sensitivity of 10 copies/mL. When seamlessly integrated with a high-flow aerosol sampler, our microdevice can achieve a sub-single molecule spatial resolution of 0.83 copies/m3 for airborne virus surveillance. We then designed a series of virus-in-aerosols monitoring systems (RIAMs), including versions of a multi-site sampling RIAMs (M-RIAMs), a stationary real-time RIAMs (S-RIAMs), and a roaming real-time RIAMs (R-RIAMs) for different application scenarios. Using M-RIAMs, we performed a comprehensive evaluation of 210 environmental samples from COVID-19 patient wards, including 30 aerosol samples. The highest positive detection rate of aerosol samples (60%) proved the aerosol-based SARS-CoV-2 monitoring represents an effective method for spatial risk assessment. The detection of 78 aerosol samples in real-world settings via S-RIAMs confirmed its reliability for ultra-sensitive and continuous airborne virus monitoring. Therefore, RIAMs shows the potential as an effective solution for mitigating the risk of airborne virus transmission.

Oral Azvudine (FNC) Tablets in Patients infected with SARS-CoV-2 Omicron Variant: A Retrospective Cohort Study (preprint)

BackgroundThere is a lack of data on the efficacy of oral Azvudine in Coronavirus Disease treatment. This study aimed to assess the association between Azvudine treatment and clinical outcomes in a cohort of patients infected with the SARS-CoV-2 Omicron variant. MethodsThis is a retrospective study conducted in two mobile cabin hospitals. All consecutive patients with a diagnosis of COVID-19 admitted from August to October 2022 were included in the study. Linear regression models and Cox proportional hazards models were used to assess the association between Azvudine treatment and time to obtain the first negative nucleic acid test results. ResultsA total of 207 patients were analyzed, of whom 166 patients (80.2%) received Azvudine treatment after hospitalization, and the rest did not. Linear regression models showed that Azvudine treatment was associated with reduced time to obtain the first negative nucleic acid test results after adjusting for age and gender [mean difference = -1.658; 95% CI: -2.772 to -0.544, P = 0.0039]. The multivariable Cox analysis conforms to the results from the linear regression model (hazard ratio = 1.461; 95% CI: 1.01 to 2.11, P = 0.044). ConclusionAzvudine treatment was associated with reduced virus shedding time. Further studies are needed to confirm our findings.

Transcriptomic Characteristics and Impaired Immune Function of Patients Who Retest Positive for SARS-CoV-2 RNA (preprint)

Background: The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has gradually become a global public health crisis. Some patients who have recovered from COVID-19 subsequently tested positive again for SARS-CoV-2 after discharge (retesting-positive, RTP). However, the underlying mechanism is unknown.Methods: Here, 30 RTP patients, 20 convalescent patients, and 20 healthy controls were enrolled for analysis of the immunological characteristics of their peripheral blood mononuclear cells (PBMCs). Furthermore, we sought to comprehensively characterize the transcriptional changes in the three groups by transcriptome sequencing.Findings: It was found that the absolute numbers of CD4+ T cells, CD8+ T cells, and NK cells were not decreased remarkably, while the expression of activation markers on these cells was significantly decreased in RTP patients. Furthermore, the percentage of granzyme B-producing T cells was also decreased in RTP patients compared with that in convalescent patients. Moreover, the high expression of inhibitor of differentiation-1 (ID1) and the low expression of IFITM10 may be associated with the insufficient activation of immune cells and RTP occurrence.Interpretation: Our findings provide insights into the impaired immune function and pathogenesis of RTP occurrence in COVID-19, which may contribute to the development of immunotherapy for RTP patients.Funding Statement: This work was supported by China National Center for Biotechnology Development (2020YFC0843800 and 2020YFC0846800), Ministry of Science and Technology of China (2020TFC0844100), and China Postdoctoral Science Foundation (2020T130112ZX).Declaration of Interests: The authors declare no potential conflict of interest.Ethics Approval Statement: The studies were approved by the Ethics Committee of the First Affiliated Hospital of the University of Science & Technology of China (2020-XG(H)-005) and Peking University First Hospital (2020-Research-112) for Emerging Infectious Diseases. Experiments were conducted in accordance with the ethical guidelines of the 1975 Declaration of Helsinki, the Principles of Good Clinical Practice, and the guidelines of China’s regulatory requirements.

The SARS-CoV-2 RNA with mild pulmonary consolidation lasts longer in non-severe COVID-19 patients: an observational study (preprint)

Background: Since December 2019, COVID-19 has rapidly swept the world. It is particularly important to understand the dynamic changes of the whole disease course of non-severe patients from the onset to the follow-up after discharge.Methods: On February 1, 2020, 18 cases of non-severe COVID-19 appeared in a hospital in Beijing. All patients were SARS-CoV-2 RNA positive by RT-PCR for pharyngeal swabs. We recorded the clinical information and viral dynamics of these patients from the onset of the disease to 2 months after discharge. According to the severity of lung consolidation, 18 patients were divided into two groups (mild pulmonary consolidation group [imaging score ≤10]; severe pulmonary consolidation group [imaging score >10]).Results: Eighteen patients (median age 43) were included, including 14 females. Fever (11/18) and cough (8/18) were the most common symptoms. The duration of SARS-CoV-2 RNA positive in mild pulmonary consolidation group was significantly longer than severe pulmonary consolidation group (the median time was 30 days and 13 days, respectively, P= 0.0031). Two months after discharge, almost all patients were followed up for IgM antibody disappearance and IgG antibody production.Conclusion: In non-severe COVID-19 patients, the positive duration of the SARS-CoV-2 RNA in patients with mild pulmonary consolidation was longer than the severe pulmonary consolidation. However, it is necessary for a large sample to verify our conclusions.