The relationship between ABO blood group distribution of COVID-19 convalescents and the plasma antibody titer against SARS-CoV-2

Objective: To perform a statistical analysis of the ABO blood group distribution of COVID-19 convalescents, and further analyze the ABO blood group distribution in COVID-19 convalescents with different plasma antibody titer against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

A novel strategy for the detection of SARS-CoV-2 variants based on multiplex PCR-MALDI-TOF MS (preprint)

Background The second wave of coronavirus disease 2019 (COVID-19) has been incessantly causing catastrophe worldwide, and the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants causes further uncertainty regarding epidemic risk. Here, a novel strategy for the detection of SARS-CoV-2 variants using multiplex PCR coupled with MALDI-TOF MS was developed. Methods Plasmids carrying gene sequences containing 9 mutation types in 7 mutated sites (HV6970del, N501Y, K417N, P681H, D614G, E484K, L452R, E484Q and P681R) in the receptor-binding domain of the spike protein of SARS-CoV-2 variants were synthesized. Using the nucleic acid sequence of SARS-CoV-2 nonvariant and a synthetic SARS-CoV-2-variant-carrying plasmid, a MALDI-TOF MS method based on the single-base mass probe extension of multiplex PCR amplification products was established to detect the above nine mutation types. The detection limit of this method was determined via the concentration gradient method. Twenty-one respiratory tract pathogens (9 bacteria, 11 respiratory viruses) and pharyngeal swab nucleic acid samples from healthy people were selected for specific validation. Sixteen samples from COVID-19 patients were used to verify the accuracy of this method. Results The 9 mutation types could be detected simultaneously by triple PCR amplification coupled with MALDI-TOF MS. SARS-CoV-2 and all six variants (B.1.1.7, B.1.351, B.1.429, B.1.526, P.1 and B.1.617) could be identified. The detection limit for all 9 sites was 1.5×10 3 copies. The specificity of this method was 100%, and the accuracy of real-time PCR CT values less than 30 among positive samples was 100%. This method is open and extensible, and can be used in a high-throughput manner, easily allowing the addition of new mutation sites as needed to identify and track new SARS-CoV-2 variants as they emerge. Conclusions Multiplex PCR-MALDI-TOF MS provides a new detection option with practical application value for SARS-CoV-2 and its variant infection. Key point An all-in-one SARS-CoV-2 variant identification method based on a multiplex PCR-MALDI-TOF MS system was developed. All of the SARS-CoV-2 variants can be identified based on 9 types of 7 mutated sites of RBD of spike protein using this method.

Systematic review and meta-analysis of the prevalence of venous thromboembolic events in novel coronavirus disease-2019 patients.

BACKGROUND: Emerging clinical evidence has shown that patients with the novel coronavirus disease-2019 (COVID-19) have complications that include venous thromboembolism (VTE), consisting of deep vein thrombosis (DVT) and pulmonary embolism (PE). The prevalence of VTE in patients hospitalized with COVID-19 is unclear. METHODS: Eligible studies on COVID-19 were collected from PubMed, Web of Science, and Embase. Patient characteristics and information were extracted for three categories of patients: consecutive, ICU, and non-ICU group. All PEs and DVTs were diagnosed by computed tomographic pulmonary arteriography and duplex ultrasound examination, respectively. A subgroup analysis of testing strategies in ICU and non-ICU patients for PE and DVT was also performed. RESULTS: Forty clinical studies involving 7966 patients hospitalized with COVID-19 were included. Pooled VTE prevalence was 13% in consecutive patients (95% confidence interval [CI], 0.05-0.24; I2 = 97%), 7% in non-ICU patients (95% CI, 0.01-0.18; I2 = 93%), and 31% in ICU patients (95% CI, 0.22-0.42; I2 = 91%). ICU patients had the highest prevalence of PE among the three groups (17% [95% CI, 0.12-0.23] vs 8% in consecutive patients [95% CI, 0.04-0.13], 4% in non-ICU patients [95% CI, 0.01-0.08]). ICU patients also had the highest DVT prevalence (25% [95% CI, 0.14-0.37] vs 7% in consecutive patients [95% CI, 0.03-0.14], and 7% in non-ICU [95% CI, 0.02-0.14]). The subgroup analysis showed a three-fold improvement in the PE and DVT detection rates in both ICU and non-ICU patients with COVID-19 when the screening test for VTE was applied. In the settings of screening tests for VTE, ICU patients have a significantly higher prevalence of PE (37% vs 10%; P < .0001) and DVT (40% vs 12%; P = .0065) compared with non-ICU patients. CONCLUSIONS: VTE is common in patients hospitalized with COVID-19, especially among ICU patients. Screening tests for PE and DVT may significantly improve detection rates in both ICU and non-ICU patients with COVID-19 than tests based on clinical suspicion.

Long-term Co-existence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) with Antibody Response in Non-severe Coronavirus Disease 2019 (COVID-19) Patients (preprint)

Severe acute respiratory syndrome coronavirus 2 infection causing coronavirus disease 2019 has spread worldwide. Whether antibodies are important for the adaptive immune responses against SARS-CoV-2 infection needs to be determined. Here, 26 cases of COVID-19 in Jinan, China, were examined and shown to be mild or with common clinical symptoms and no cases of severe symptoms were found among these patients. A striking feature of some patients is that SARS-CoV-2 could exist in patients who have virus-specific IgG antibodies for a very long period, with one case for up to 36 days. One COVID-19 patient who did not produce any SARS-CoV-2-bound IgG successfully cleared SARS-CoV-2 after 46 days of illness, revealing that without antibody-mediated adaptive immunity, innate immunity may still be powerful enough to eliminate SARS-CoV-2. Overall, this report may provide a basis for further analysis of both innate and adaptive immunity in SARS-CoV-2 clearance, especially in non-severe cases. This study also has implications for understanding the pathogenesis and treatment of SARS-CoV-2.

COVID-19: Melatonin as a potential adjuvant treatment.

This article summarizes the likely benefits of melatonin in the attenuation of COVID-19 based on its putative pathogenesis. The recent outbreak of COVID-19 has become a pandemic with tens of thousands of infected patients. Based on clinical features, pathology, the pathogenesis of acute respiratory disorder induced by either highly homogenous coronaviruses or other pathogens, the evidence suggests that excessive inflammation, oxidation, and an exaggerated immune response very likely contribute to COVID-19 pathology. This leads to a cytokine storm and subsequent progression to acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) and often death. Melatonin, a well-known anti-inflammatory and anti-oxidative molecule, is protective against ALI/ARDS caused by viral and other pathogens. Melatonin is effective in critical care patients by reducing vessel permeability, anxiety, sedation use, and improving sleeping quality, which might also be beneficial for better clinical outcomes for COVID-19 patients. Notably, melatonin has a high safety profile. There is significant data showing that melatonin limits virus-related diseases and would also likely be beneficial in COVID-19 patients. Additional experiments and clinical studies are required to confirm this speculation.