Detection of Anti-SARS-CoV-2-S2 IgG Is More Sensitive Than Anti-RBD IgG in Identifying Asymptomatic COVID-19 Patients.

Characterizing the serologic features of asymptomatic SARS-CoV-2 infection is imperative to improve diagnostics and control of SARS-CoV-2 transmission. In this study, we evaluated the antibody profiles in 272 plasma samples collected from 59 COVID-19 patients, consisting of 18 asymptomatic patients, 33 mildly ill patients and 8 severely ill patients. We measured the IgG against five viral structural proteins, different isotypes of immunoglobulins against the Receptor Binding Domain (RBD) protein, and neutralizing antibodies. The results showed that the overall antibody response was lower in asymptomatic infections than in symptomatic infections throughout the disease course. In contrast to symptomatic patients, asymptomatic patients showed a dominant IgG-response towards the RBD protein, but not IgM and IgA. Neutralizing antibody titers had linear correlations with IgA/IgM/IgG levels against SARS-CoV-2-RBD, as well as with IgG levels against multiple SARS-CoV-2 structural proteins, especially with anti-RBD or anti-S2 IgG. In addition, the sensitivity of anti-S2-IgG is better in identifying asymptomatic infections at early time post infection compared to anti-RBD-IgG. These data suggest that asymptomatic infections elicit weaker antibody responses, and primarily induce IgG antibody responses rather than IgA or IgM antibody responses. Detection of IgG against the S2 protein could supplement nucleic acid testing to identify asymptomatic patients. This study provides an antibody detection scheme for asymptomatic infections, which may contribute to epidemic prevention and control.

Association between detectable SARS-COV-2 RNA in anal swabs and disease severity in patients with coronavirus disease 2019.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was found in the intestines and feces, but its clinical significance is not completely clear. We aim to characterize the longitudinal test results of SARS-CoV-2 RNA in anal swabs and to explore the association with disease severity. METHODS: We included laboratory-confirmed coronavirus disease 2019 (COVID-19) patients, who were hospitalized in Guangzhou Eighth People's Hospital and excluded those who had not received anal swabs for SARS-COV-2 RNA testing. Epidemiological, clinical, and laboratory data were obtained. Throat swabs and anal swabs were collected periodically for SARS-COV-2 RNA detection. RESULTS: Two hundred and seventeen eligible patients (median aged 50 years, 50.2% were females) were analyzed. 21.2% (46/217) of the patients were detected with SARS-CoV-2 RNA in anal swabs. The duration of viral RNA was longer, but the viral load was lower in anal swabs than throat swabs in the early stage of the disease. During a median follow-up of 20 days, 30 (13.8%) patients were admitted to the intensive care unit (ICU) for high-flow nasal cannula or higher-level oxygen support measures to correct hypoxemia. Detectable viral RNA in anal swabs (adjusted hazard ratio [aHR], 2.50; 95% confidence interval [CI], 1.20-5.24), increased C-reactive protein (aHR, 3.14; 95% CI, 1.35-7.32) and lymphocytopenia (aHR, 3.12; 95% CI, 1.46-6.67) were independently associated with ICU admission. The cumulative incidence of ICU admission was higher among patients with detectable viral RNA in anal swabs (26.3% vs 10.7%, P = .006). CONCLUSION: Detectable SARS-CoV-2 RNA in the digestive tract was a potential warning indicator of severe disease.

Factors associated with clinical outcomes in patients with Coronavirus Disease 2019 in Guangzhou, China.

BACKGROUND: Coronavirus Disease 2019 (COVID-19) is threatening billions of people. We described the clinical characteristics and explore virological and immunological factors associated with clinical outcomes. METHODS: 297 COVID-19 patients hospitalized in Guangzhou Eighth People's Hospital between January 20 and February 20, 2020 were included. Epidemiological, clinical and laboratory data were collected and analyzed. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) RNA in respiratory tract, blood samples and digestive tract was detected and lymphocyte subsets were tested periodically. RESULT: Among the 297 patients (median age of 48 years), 154 (51.9 %) were female, 245 (82.5 %) mild/moderate cases, and 52 (17.5 %) severe/critical cases. 270 patients were detected for SARS-CoV-2 RNA in anal swabs and/or blood samples, and the overall positive rate was 23.0 % (62/270), higher in severe/critical cases than in mild/moderate cases (52.0 % vs. 16.4 %, P < 0.001). The CD4/CD8 ratio on admission was significantly higher in severe/critical cases than in mild/moderate cases (1.84 vs. 1.50, P = 0.022). During a median follow-up period of 17 days, 36 (12.1 %) patients were admitted to intensive care unit (ICU), 16 (5.4 %) patients developed respiratory failure and underwent mechanical ventilation, four (1.3 %) patients needed extracorporeal membrane oxygenation (ECMO), only one (0.34 %) patients died of multiple organ failure. Detectable SARS-CoV-2 RNA in anal swabs and/or blood samples, as well as higher CD4/CD8 ratio were independent risk factors of respiratory failure and ICU admission. CONCLUSIONS: Most of COVID-19 patients in Guangzhou are mild/moderate, and presence of extrapulmonary virus and higher CD4/CD8 ratio are associated with higher risk of worse outcomes.

Efficacy and Safety of Lopinavir/Ritonavir or Arbidol in Adult Patients with Mild/Moderate COVID-19: An Exploratory Randomized Controlled Trial.

BACKGROUND: Antiviral therapies against the novel coronavirus SARS-CoV-2, which has caused a global pandemic of respiratory illness called COVID-19, are still lacking. METHODS: Our study (ClinicalTrials.gov: NCT04252885, named ELACOI), was an exploratory randomized (2:2:1) controlled trial assessing the efficacy and safety of lopinavir/ritonavir (LPV/r) or arbidol monotherapy for treating patients with mild/moderate COVID-19. FINDINGS: This study successfully enrolled 86 patients with mild/moderate COVID-19, with 34 randomly assigned to receive LPV/r, 35 to arbidol, and 17 with no antiviral medication as control. Baseline characteristics of the three groups were comparable. The primary endpoint, the rate of positive-to-negative conversion of SARS-CoV-2 nucleic acid, was similar between groups (all p > 0.05). There were no differences between groups in the secondary endpoints, the rates of antipyresis, cough alleviation, or improvement of chest computed tomography (CT) at days 7 or 14 (all p > 0.05). At day 7, 8 (23.5%) patients in the LPV/r group, 3 (8.6%) in the arbidol group, and 2 (11.8%) in the control group showed a deterioration in clinical status from moderate to severe/critical (p = 0.206). Overall, 12 (35.3%) patients in the LPV/r group and 5 (14.3%) in the arbidol group experienced adverse events during the follow-up period. No apparent adverse event occurred in the control group. CONCLUSIONS: LPV/r or arbidol monotherapy present little benefit for improving the clinical outcome of patients hospitalized with mild/moderate COVID-19 over supportive care. FUNDING: This study was supported by project 2018ZX10302103-002, 2017ZX10202102-003-004, and Infectious Disease Specialty of Guangzhou High-level Clinical Key Specialty (2019-2021).

Detectable 2019-nCoV viral RNA in blood is a strong indicator for the further clinical severity.

The novel coronavirus (2019-nCoV) infection caused pneumonia. we retrospectively analyzed the virus presence in the pharyngeal swab, blood, and the anal swab detected by real-time PCR in the clinical lab. Unexpectedly, the 2109-nCoV RNA was readily detected in the blood (6 of 57 patients) and the anal swabs (11 of 28 patients). Importantly, all of the 6 patients with detectable viral RNA in the blood cohort progressed to severe symptom stage, indicating a strong correlation of serum viral RNA with the disease severity (p-value = 0.0001). Meanwhile, 8 of the 11 patients with annal swab virus-positive was in severe clinical stage. However, the concentration of viral RNA in the anal swab (Ct value = 24 + 39) was higher than in the blood (Ct value = 34 + 39) from patient 2, suggesting that the virus might replicate in the digestive tract. Altogether, our results confirmed the presence of virus RNA in extra-pulmonary sites.