Diagnosis and Treatment Strategy of Nasogenic Olfactory Dysfunction.

Since the global outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a symptom of the onset of SARS-CoV-2, olfactory dysfunction (OD), has attracted tremendous attention. OD is not only a negative factor for quality of life but also an independent hazard and early biomarker for various diseases, such as Parkinson's and Huntington's diseases. Therefore, early identification and treatment of OD in patients are critical. Many etiological factors are responsible for OD based on current opinions. Sniffin'Sticks are recommended to identify the initial position (central or peripheral) for OD when treating patients clinically. It is worth emphasizing that the olfactory region in nasal cavity is recognized as the primary and critical olfactory receptor. Many nasal diseases, such as those with traumatic, obstructive and inflammatory causes, can lead to OD. The key question is no refined diagnosis or treatment strategy for nasogenic OD currently. This study summarizes the differences in medical history, symptoms, auxiliary examination, treatment and prognosis of different types of nasogenic OD by analyzing the current studies. We propose using olfactory training after 4-6 weeks of initial treatment for nasogenic OD patients with no significant improvement in olfaction. We hope that our research can provide valuable clinical guidance by systematically summarizing the clinical characteristics of nasogenic OD.

Quantitative detection of SARS-CoV-2 antigen: an effective approach for evaluating the infectivity of COVID- 19 convalescent patients (preprint)

BackgroundThis study evaluated the quantitative detection of SARS-CoV-2 antigen by the MAGLUMI chemiluminescent immunoassay (MAG-CLIA) in COVID-19 patients during the peak of COVID-19 Shanghai epidemics in a tertiary hospital in Shanghai.MethodsAnalytical performances of the MAG-CLIA were evaluated, including precision, limit of quantitation (LoQ), linearity and specificity. Nasopharyngeal specimens from 232 patients who were SARS-CoV-2 RT-qPCR positive and from 477 healthy donors were included to evaluate the diagnostic performance. The performance of the Wondfo antigen-detecting lateral flow test (LFT) was evaluated in parallel. The longitudinal studies were performed by monitoring antigen concentrations alongside with RT-qPCR results in 14 COVID-19 participants for up to 22 days. The critical antigen concentration in determining virus infectivity was evaluated at the reference cycle threshold (Ct) of 35.ResultsCOVID-19 patients were well-identified using an optimal threshold of 0.64 pg/mL antigen concentration, with sensitivity and specificity of 95.7% (95% CI: 92.2%-97.9%) and 98.3% (95% CI: 96.7%-99.3%), respectively, while the Wondfo LFT exhibited those of 34.9% (95% CI: 28.8%-41.4%) and 100% (95% CI: 99.23%-100%), respectively. Close dynamic consistence was observed between SARS-CoV-2 Ag and viral load time series in the longitudinal studies. The critical value of 8.82 pg/mL antigen showed adequate sensitivity and specificity in evaluating the infectivity of convalescent patients.ConclusionsThe MAG-CLIA SARS-CoV-2 Ag detection is an effective and alternative approach for rapid diagnosis and enables us to evaluate the infectivity of convalescent patients.

Reduced neutralization of SARS-CoV-2 B.1.617 variant by inactivated and RBD-subunit vaccine (preprint)

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The Spike protein that mediates coronavirus entry into host cells is a major target for COVID-19 vaccines and antibody therapeutics. However, multiple variants of SARS-CoV-2 have emerged, which may potentially compromise vaccine effectiveness. Using a pseudovirus-based assay, we evaluated SARS-CoV-2 cell entry mediated by the viral Spike B.1.617 and B.1.1.7 variants. We also compared the neutralization ability of monoclonal antibodies from convalescent sera and neutralizing antibodies (NAbs) elicited by CoronaVac (inactivated vaccine) and ZF2001 (RBD-subunit vaccine) against B.1.617 and B.1.1.7 variants. Our results showed that, compared to D614G and B.1.1.7 variants, B.1.617 shows enhanced viral entry and membrane fusion, as well as more resistant to antibody neutralization. These findings have important implications for understanding viral infectivity and for immunization policy against SARS-CoV-2 variants.