Myricetin possesses the potency against SARS-CoV-2 infection through blocking viral-entry facilitators and suppressing inflammation in rats and mice.

BACKGROUND: Myricetin (3,5,7-trihydroxy-2-(3,4,5-tri hydroxyphenyl)-4-benzopyrone) is a common flavonol extracted from many natural plants and Chinese herb medicines and has been demonstrated to have multiple pharmacological activities, such as anti-microbial, anti-thrombotic, neuroprotective, and anti-inflammatory effects. Previously, myricetin was reported to target Mpro and 3CL-Pro-enzymatic activity to SARS-CoV-2. However, the protective value of myricetin on SARS-Cov-2 infection through viral-entry facilitators has not yet been comprehensively understood. PURPOSE: The aim of the current study was to evaluate the pharmacological efficacy and the mechanisms of action of myricetin against SARS-CoV-2 infection both in vitro and in vivo. METHODS: The inhibitory effects of myricetin on SARS-CoV-2 infection and replication were assessed on Vero E6 cells. Molecular docking analysis and bilayer interferometry (BLI) assays, immunocytochemistry (ICC), and pseudoviruses assays were performed to evaluate the roles of myricetin in the intermolecular interaction between the receptor binding domain (RBD) of the SARS-CoV-2 spike (S) protein and angiotensin-converting enzyme 2 (ACE2). The anti-inflammatory potency and mechanisms of myricetin were examined in THP1 macrophages in vitro, as well as in carrageenan-induced paw edema, delayed-type hypersensitivity (DTH) induced auricle edema, and LPS-induced acute lung injury (ALI) animal models. RESULTS: The results showed that myricetin was able to inhibit binding between the RBD of the SARS-CoV-2 S protein and ACE2 through molecular docking analysis and BLI assay, demonstrating its potential as a viral-entry facilitator blocker. Myricetin could also significantly inhibit SASR-CoV-2 infection and replication in Vero E6 cells (EC50 55.18 µM), which was further validated with pseudoviruses containing the RBD (wild-type, N501Y, N439K, Y453F) and an S1 glycoprotein mutant (S-D614G). Moreover, myricetin exhibited a marked suppressive action on the receptor-interacting serine/threonine protein kinase 1 (RIPK1)-driven inflammation and NF-kappa B signaling in THP1 macrophages. In animal model studies, myricetin notably ameliorated carrageenan-induced paw edema in rats, DTH induced auricle edema in mice, and LPS-induced ALI in mice. CONCLUSION: Our findings showed that myricetin inhibited HCoV-229E and SARS-CoV-2 replication in vitro, blocked SARS-CoV-2 virus entry facilitators and relieved inflammation through the RIPK1/NF-κB pathway, suggesting that this flavonol has the potential to be developed as a therapeutic agent against COVID-19.

Driving forces and variation in water footprint before and after the COVID-19 lockdown in Fujian Province, China

The COVID-19 outbreak has injured the global industrial supply chain, especially China as the world's largest manufacturing base. Since 2020, China has implemented a rigorous lockdown policy, which has sternly damaged sectoral trade in export-oriented coastal areas. Fujian Province, which mainly processes imported materials, has a more profound influence. Although the COVID-19 lockdown has had some detrimental consequences on the world economy, it also had some favorable benefits on the global ecology. Previous studies have shown that the lockdown has altered the physical water quantity and quality, but the lack of total, virtual, and physical water research that combines water quantity and water quality simultaneously to pinpoint the subject and responsibility of water resources consumption and pollution. This research quantified the physical, virtual, and total water consumption and water pollution among 30 sectors in Fujian Province based on the theory of water footprint and the Economic Input-Output Life Cycle Assessment model. SDA model was then used to investigate the socioeconomic elements that underpin variations in the water footprint. The results show that after the lockdown, the physical water quantity and the physical grey WF in Fujian Province decreased by 2.6 Gm3 (−6.7%) and 0.4 Gm3 (−1.3%) respectively. The virtual water quantity decreased by 2.3 Gm3 (−4.5%), whereas the virtual grey WF rose by 1.5 Gm3 (4.3%). The total water quantity dropped by 3.3 Gm3 (−4.9%), while the grey WF increased by 1.2 Gm3 (2.5%), i.e. the COVID-19 lockdown decreases physical water quantity and improves local water quality. More than 50% of the water comes from virtual water trade outside the province (virtual water is highly dependent on external), and around 60% of the grey WF comes from physical sewage in the province. The COVID-19 lockdown reduced water outsourcing across the province (paid nonlocally decrease) but increased pollution outsourcing (paid nonlocally increase). And gross capital formation's contribution to the growth in water footprint will continue to rise. As a result, this study suggested that Fujian should take advantage of sectoral trade network to enhance the transaction of green water-intensive intermediate products, reduce the physical water consumption of blue water-intensive sectors, and reduce the external dependence on water consumption. Achieving the shared responsibility of upstream and downstream water consumption and reducing the external dependence on water in water-rich regions is crucial to solving the world's water problems. This research provides empirical evidence for the long-term effects of COVID-19 lockdown on the physical and virtual water environment. Graphical abstract Image 1

Driving forces and variation in water footprint before and after the COVID-19 lockdown in Fujian Province of China.

The COVID-19 outbreak has injured the global industrial supply chain, especially China as the world's largest manufacturing base. Since 2020, China has implemented a rigorous lockdown policy, which has sternly damaged sectoral trade in export-oriented coastal areas. Fujian Province, which mainly processes imported materials, has a more profound influence. Although the COVID-19 lockdown has had some detrimental consequences on the world economy, it also had some favorable benefits on the global ecology. Previous studies have shown that the lockdown has altered the physical water quantity and quality, but the lack of total, virtual, and physical water research that combines water quantity and water quality simultaneously to pinpoint the subject and responsibility of water resources consumption and pollution. This research quantified the physical, virtual, and total water consumption and water pollution among 30 sectors in Fujian Province based on the theory of water footprint and the Economic Input-Output Life Cycle Assessment model. SDA model was then used to investigate the socioeconomic elements that underpin variations in the water footprint. The results show that after the lockdown, the physical water quantity and the physical grey WF in Fujian Province decreased by 2.6 Gm3 (-6.7%) and 0.4 Gm3 (-1.3%) respectively. The virtual water quantity decreased by 2.3 Gm3 (-4.5%), whereas the virtual grey WF rose by 1.5 Gm3 (4.3%). The total water quantity dropped by 3.3 Gm3 (-4.9%), while the grey WF increased by 1.2 Gm3 (2.5%), i.e. the COVID-19 lockdown decreases physical water quantity and improves local water quality. More than 50% of the water comes from virtual water trade outside the province (virtual water is highly dependent on external), and around 60% of the grey WF comes from physical sewage in the province. The COVID-19 lockdown reduced water outsourcing across the province (paid nonlocally decrease) but increased pollution outsourcing (paid nonlocally increase). And gross capital formation's contribution to the growth in water footprint will continue to rise. As a result, this study suggested that Fujian should take advantage of sectoral trade network to enhance the transaction of green water-intensive intermediate products, reduce the physical water consumption of blue water-intensive sectors, and reduce the external dependence on water consumption. Achieving the shared responsibility of upstream and downstream water consumption and reducing the external dependence on water in water-rich regions is crucial to solving the world's water problems. This research provides empirical evidence for the long-term effects of COVID-19 lockdown on the physical and virtual water environment.

Causal association of the brain structure with the susceptibility, hospitalization, and severity of COVID-19: A large-scale genetic correlation study.

Brain structure is related to its ability to resist external pathogens. Furthermore, there are several abnormal anatomical brain events and central system symptoms associated with COVID-19. This study, which was conducted based on genetic variables, aimed to identify the causal association between brain structure and COVID-19 phenotypes. We performed a two-sample bidirectional Mendelian randomization analysis using genetic variables obtained from large genome-wide association studies as instruments to identify the potential causal effects of various brain imaging-derived phenotypes (BIDPs) traits on susceptibility, hospitalisation, and severity of COVID-19. We explored the genetic correlations of 1325 BIDPs with the susceptibility, hospitalisation, and severity of COVID-19 using Linkage Disequilibrium Score Regression. We observed a causal relationship between increased cortical thickness of the left inferior temporal area and an increased risk of increased COVID-19 infection (p = 4.29 × 10-4) and hospitalisation (p = 3.67 × 10-3). Moreover, the larger total surface area of the whole brain was negatively correlated with the risk of hospitalisation for COVID-19. Furthermore, there was a significant causal association between increased cerebrospinal fluid volume and decreased severity of COVID-19 (p = 3.74 × 10-3). In a conclusion, we provide new insights into the causal association between BIDPs and COVID-19 phenotypes, which may help elucidate the aetiology of COVID-19.

Testing and signal identification for two-sample high-dimensional covariances via multi-level thresholding

The paper considers testing and signal identification for covariance matrices from two populations of marginally sub-Gaussian distributed. A multi-level thresholding procedure is proposed for testing the equality of two high-dimensional covariance matrices, which is designed to detect sparse and faint differences between the covariances. A novel U-statistic composition is developed to establish the asymptotic distribution of the thresholding statistics in conjunction with the matrix blocking and the coupling techniques. It is shown that the proposed test is more powerful than the existing tests in detecting sparse and weak signals in covariances. Multiple testing procedures are constructed to discover different covariances and the sub-groups of variables with different covariance structures between the two populations. The proposed procedures are based on the multi-level thresholding test, which are able to control the false discovery proportion (FDP) with high power. Simulation experiments and a case study on the returns of the S&P 500 stocks before and after the COVID-19 pandemic are conducted to demonstrate and compare the utilities of the proposed methods.

Remote Sensing Evidence for Significant Variations in the Global Gross Domestic Product during the COVID-19 Epidemic

Coronavirus disease 2019 (COVID-19) has been spreading rapidly and is still threatening human health currently. A series of measures for restraining epidemic spreading has been adopted throughout the world, which seriously impacted the gross domestic product (GDP) globally. However, details of the changes in the GDP and its spatial heterogeneity characteristics on a fine scale worldwide during the pandemic are still uncertain. We designed a novel scheme to simulate a 0.1°×0.1°resolution grid global GDP map during the COVID-19 pandemic. Simulated nighttime-light remotely sensed data (SNTL) was forecasted via a GM(1, 1) model under the assumption that there was no COVID-19 epidemic in 2020. We constructed a geographically weighted regression (GWR) model to determine the quantitative relationship between the variation of nighttime light (ΔNTL) and the variation of GDP (ΔGDP). The scheme can detect and explain the spatial heterogeneity of ΔGDP at the grid scale. It is found that a series of policies played an obvious role in affecting GDP. This work demonstrated that the global GDP, except for in a few countries, represented a remarkably decreasing trend, whereas the ΔGDP exhibited significant differences.

Nucleic acid amplification with specific signal filtration and magnification for ultrasensitive colorimetric detection.

Recently, sensitive, fast and low cost nucleic acid isothermal amplification technologies (such as loop-mediated isothermal amplification, LAMP) have attracted great attention in the urgent needs of point-of-care testing (POCT) and regular epidemic prevention and control. However, unlike PCR which usually employs TaqMan probe to report specific signals, specific-signal-output strategies in isothermal amplification are immature and visual detection even rare, which limits their popularity in POCT. We hypothesize to address this issue by designing a visual-signal-report system to both filtrate and magnify the target information in isothermal amplification. In this work, we developed a specific signal filtration and magnification colorimetric isothermal sensing platform (SFMC for short) for ultrasensitive detection of DNA and RNA. SFMC consists of two processes: an isothermal amplification with specific signal filtration and a self-replication catalyzed hairpin assembly (SRCHA) for rapid target-specific signal magnification and outputting. With these unique properties, this biosensing platform could detect target DNA as low as 5 copies per reaction and target RNA as low as 10 copies per reaction by naked eyes. Benefited from the excellent colorimetric detection performance, this biosensing platform has been successfully used for African swine fever virus (ASFV) and SARS-CoV-2 detection.

Investigation of the determinants for misinformation correction effectiveness on social media during COVID-19 pandemic.

The rapid dissemination of misinformation in social media during the COVID-19 pandemic triggers panic and threatens the pandemic preparedness and control. Correction is a crucial countermeasure to debunk misperceptions. However, the effective mechanism of correction on social media is not fully verified. Previous works focus on psychological theories and experimental studies, while the applicability of conclusions to the actual social media is unclear. This study explores determinants governing the effectiveness of misinformation corrections on social media with a combination of a data-driven approach and related theories on psychology and communication. Specifically, referring to the Backfire Effect, Source Credibility, and Audience's role in dissemination theories, we propose five hypotheses containing seven potential factors (regarding correction content and publishers' influence), e.g., the proportion of original misinformation and warnings of misinformation. Then, we obtain 1487 significant COVID-19 related corrections on Microblog between January 1st, 2020 and April 30th, 2020, and conduct annotations, which characterize each piece of correction based on the aforementioned factors. We demonstrate several promising conclusions through a comprehensive analysis of the dataset. For example, mentioning excessive original misinformation in corrections would not undermine people's believability within a short period after reading; warnings of misinformation in a demanding tone make correction worse; determinants of correction effectiveness vary among different topics of misinformation. Finally, we build a regression model to predict correction effectiveness. These results provide practical suggestions on misinformation correction on social media, and a tool to guide practitioners to revise corrections before publishing, leading to ideal efficacies.

Comparative clinical analysis of fever in tumor patients, normal patients, and those infected with new coronavirus pneumonia.

BACKGROUND: Under the current epidemic of the coronavirus disease of 2019 (COVID-19), there is a need to distinguish the differences between the laboratory examinations of COVID-19-infected patients, tumor patients with fever, and those with normal fever patients. We aimed to investigate the temperature of tumor patients with different tumor burdens, stages, and cancer types. METHODS: We recruited 3 groups of patients to this study: fever patients with malignant tumors, ordinary fever patients, and confirmed cases of COVID-19, with 31, 55, and 28 cases in each group, respectively. RESULTS: The levels of leukocytes and neutrophils were the highest among non-tumor patients, and the count of COVID-19 was the lowest, with a P value of 0.000. Among the leukocytosis group, non-tumor patients had the highest proportion (43.6%), while that of COVID-19 was only 3.6% (P=0.000). Similarly, there were significant differences in the grading of neutrophils, where most of the infected patients were in the normal group and the P value was 0.000. The lymphocyte count of the tumor group was significantly reduced, with an average of (0.97±0.66) ×109/L (P=0.004). In the lymphocyte grades, most of the infected patients were the normal group (71.4%), while tumor patients in the lymphocytopenia group accounted for 63.1% (P=0.006). There were also significant differences in the neutrophil to lymphocyte ratio (NLR) (P=0.006). There was a significant difference in temperature between different tumor burden groups (P=0.014). CONCLUSIONS: The normal fever group had the highest count of leukocyte and neutrophils, whereas the infected group had the lowest relative count. The NLR was the lowest in the infected group. The NLR was higher in the bigger tumor load group.

Unidirectional Elimination of Hydrogen by a Giant Local Field Saves First- and Last-Mile Performances of Semiconductor Devices.

Hydrogen, the smallest element, easily forms bonds to host/dopant atoms in semiconductors, which strongly passivates the original electronic characteristics and deteriorates the final reliability. Here, we demonstrate a concept of unidirectional elimination of hydrogen from semiconductor wafers as well as electronic chips through a giant local electric field induced by compact chloridions. We reveal an interactive behavior of chloridions, which can rapidly approach and take hydrogen atoms away from the device surface. A universal and simple technique based on a solution-mediated three-electrode system achieves efficient hydrogen elimination from various semiconductor wafers (p-GaN, p-AlGaN, SiC, and AlInP) and also complete light emitting diodes (LEDs). The p-type conductivity and light output efficiency of H-eliminated UVC LEDs have been significantly enhanced, and the lifetime is almost doubled. Moreover, we confirm that under a one-second irradiation of UVC LEDs, bacteria and COVID-19 coronavirus can be completely killed (>99.93%). This technology will accelerate the further development of the semiconductor-based electronic industry.

Distribution characteristics of SARS-CoV-2 IgM and IgG in false-positive results detected by Chemiluminescent immunoassay (preprint)

There have been several false-positive results in the antibody detection of the COVID-19. This study aims to analyze the distribution characteristics of SARS-CoV-2 IgM and IgG in false-positive results detected using chemiluminescent immunoassay. The characteristics of the false-positive results in SARS-CoV-2 IgM and IgG testing were retrospectively analyzed. The dynamic changes in the results of SARS-CoV-2 IgM and IgG antibodies were observed. The false-positive proportion of the single SARS-CoV-2 IgM positive results was 95.88%, which was significantly higher than those of the single SARS-CoV-2 IgG positive results (67.50%) ( P  

"Molecular Masks" for ACE2 to Effectively and Safely Block SARS-CoV-2 Virus Entry.

Coronavirus Disease 2019 (COVID-19) remains a global health crisis, despite the development and success of vaccines in certain countries. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, uses its spike protein to bind to the human cell surface receptor angiotensin-converting enzyme 2 (ACE2), which allows the virus to enter the human body. Using our unique cell screening technology, we identified two ACE2-binding peptoid compounds and developed dimeric derivatives (ACE2P1D1 and ACE2P2D1) that effectively blocked spike protein-ACE2 interaction, resulting in the inhibition of SARS-CoV-2 pseudovirus entry into human cells. ACE2P1D1 and ACE2P2D1 also blocked infection by a D614G mutant pseudovirus. More importantly, these compounds do not decrease ACE2 expression nor its enzyme activity (which is important in normal blood pressure regulation), suggesting safe applicability in humans.

[Bioinformatics Analysis of the Influence of Coronavirus Infection on Hematopoietic System and Potential Intervention Drugs and Their Significance for COVID-19].

OBJECTIVE: To analyze and predict the effect of coronavirus infection on hematopoietic system and potential intervention drugs, and explore their significance for coronavirus disease 2019 (COVID-19). METHODS: The gene expression omnibus (GEO) database was used to screen the whole genome expression data related with coronavirus infection. The R language package was used for differential expression analysis and KEGG/GO enrichment analysis. The core genes were screened by PPI network analysis using STRING online analysis website. Then the self-developed apparent precision therapy prediction platform (EpiMed) was used to analyze diseases, drugs and related target genes. RESULTS: A database in accordance with the criteria was found, which was derived from SARS coronavirus. A total of 3606 differential genes were screened, including 2148 expression up-regulated genes and 1458 expression down-regulated genes. GO enrichment mainly related with viral infection, hematopoietic regulation, cell chemotaxis, platelet granule content secretion, immune activation, acute inflammation, etc. KEGG enrichment mainly related with hematopoietic function, coagulation cascade reaction, acute inflammation, immune reaction, etc. Ten core genes such as PTPRC, ICAM1, TIMP1, CXCR5, IL-1B, MYC, CR2, FSTL1, SOX1 and COL3A1 were screened by protein interaction network analysis. Ten drugs with potential intervention effects, including glucocorticoid, TNF-α inhibitor, salvia miltiorrhiza, sirolimus, licorice, red peony, famciclovir, cyclosporine A, houttuynia cordata, fluvastatin, etc. were screened by EpiMed plotform. CONCLUSION: SARS coronavirus infection can affect the hematopoietic system by changing the expression of a series of genes. The potential intervention drugs screened on these grounds are of useful reference significance for the basic and clinical research of COVID-19.

Do air pollutants as well as meteorological factors impact Corona Virus Disease 2019 (COVID-19)? Evidence from China based on the geographical perspective.

The COVID-19 is still a huge challenge that seriously threatens public health globally. Previous studies focused on the influence of air pollutants and probable meteorological parameters on confirmed COVID-19 infections via epidemiological methods, whereas the findings of relations between possible variables and COVID-19 incidences using geographical perspective were scarce. In the present study, data concerning confirmed COVID-19 cases and possible affecting factors were collected for 325 cities across China up to May 27, 2020. The geographically weighted regression (GWR) model was introduced to explore the impact of probable determinants on confirmed COVID-19 incidences. Some results were obtained. AQI, PM2.5, and PM10 demonstrated significantly positive impacts on COVID-19 during the most study period with the majority lag group (P< 0.05). Nevertheless, the relation of temperature with COVID-19 was significantly negative (P< 0.05). Especially, CO exhibited a negative effect on COVID-19 in most study period with the majority lag group. The impacts of each possible determinant on COVID-19 represented significantly spatial heterogeneity. The obvious influence of the majority of possible factors on COVID-19 was mainly detected during the after lockdown period with the lag 21 group. Although the COVID-19 spreading has been effectively controlled by tough measures taken by the Chinese government, the study findings remind us to address the air pollution issues persistently for protecting human health.

Effects of corona virus disease-19 control measures on air quality in North China.

Corona virus disease-19 (COVID-19) has substantially reduced human activities and the associated anthropogenic emissions. This study quantifies the effects of COVID-19 control measures on six major air pollutants over 68 cities in North China by a Difference in Relative-Difference method that allows estimation of the COVID-19 effects while taking account of the general annual air quality trends, temporal and meteorological variations, and the spring festival effects. Significant COVID-19 effects on all six major air pollutants are found, with NO2 having the largest decline (-39.6%), followed by PM2.5 (-30.9%), O3 (-16.3%), PM10 (-14.3%), CO (-13.9%), and the least in SO2 (-10.0%), which shows the achievability of air quality improvement by a large reduction in anthropogenic emissions. The heterogeneity of effects among the six pollutants and different regions can be partly explained by coal consumption and industrial output data.

The efficacy assessment of convalescent plasma therapy for COVID-19 patients: a multi-center case series.

Convalescent plasma (CP) transfusion has been indicated as a promising therapy in the treatment for other emerging viral infections. However, the quality control of CP and individual variation in patients in different studies make it rather difficult to evaluate the efficacy and risk of CP therapy for coronavirus disease 2019 (COVID-19). We aimed to explore the potential efficacy of CP therapy, and to assess the possible factors associated with its efficacy. We enrolled eight critical or severe COVID-19 patients from four centers. Each patient was transfused with 200-400 mL of CP from seven recovered donors. The primary indicators for clinical efficacy assessment were the changes of clinical symptoms, laboratory parameters, and radiological image after CP transfusion. CP donors had a wide range of antibody levels measured by serology tests which were to some degree correlated with the neutralizing antibody (NAb) level. No adverse events were observed during and after CP transfusion. Following CP transfusion, six out of eight patients showed improved oxygen support status; chest CT indicated varying degrees of absorption of pulmonary lesions in six patients within 8 days; the viral load was decreased to a negative level in five patients who had the previous viremia; other laboratory parameters also tended to improve, including increased lymphocyte counts, decreased C-reactive protein, procalcitonin, and indicators for liver function. The clinical efficacy might be associated with CP transfusion time, transfused dose, and the NAb levels of CP. This study indicated that CP might be a potential therapy for severe patients with COVID-19.

[Significance and operation mode of moxibustion intervention for the group under quarantine after close contact with COVID-19].

On the base of the idea of traditional Chinese medicine as "disease prevention", the mode and the protocol of the moxibustion intervention for the group under quarantine after close contact with coronavirus disease 2019 (COVID-19) were explored. The group under quarantine after close contact with COVID-19 was taken as the subjects. By the non-contact physician-patient communication network platform co-developed by China Association of Acupuncture-Moxibustion, Hunan Provincial Association of Acupuncture-Moxibustion, Data Center of China Academy of Chinese Medical Sciences and Yuge Medicine Company, an exploratory randomized controlled trial was designed. A total of 100 cases were included and randomized into a moxibustion group and a conventional intervention group, 50 cases in each one. In the moxibustion group, moxibustion intervention was used. In the conventional intervention group, the conventional observation was adopted without moxibusiton intervention applied. The outcomes included the symptoms changes, e.g. anxiety, emotional disturbance, fatigue, headache and diarrhea, as well as whether quarantine release and the case confirmed or not, etc. The results were evaluated before intervention, in 14 days of intervention and 2 weeks after intervention separately. In this research, on the base of internet plus technology and with the internet communication platform adopted, through mobile phone WeChat App, it was to implement the subject screen, the random allocation and the instruction of moxibustion intervention as well as the quality control of patient's diary and data collection. It is anticipated that the significance and the implementation mode of moxibustion intervention can be assessed preliminarily for the group under quarantine after close contact with COVID-19.

A Method To Prevent SARS-CoV-2 IgM False Positives in Gold Immunochromatography and Enzyme-Linked Immunosorbent Assays.

We set out to investigate the interference factors that led to false-positive novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgM detection results using gold immunochromatography assay (GICA) and enzyme-linked immunosorbent assay (ELISA) and the corresponding solutions. GICA and ELISA were used to detect SARS-CoV-2 IgM in 86 serum samples, including 5 influenza A virus (Flu A) IgM-positive sera, 5 influenza B virus (Flu B) IgM-positive sera, 5 Mycoplasma pneumoniae IgM-positive sera, 5 Legionella pneumophila IgM-positive sera, 6 sera of HIV infection patients, 36 rheumatoid factor IgM (RF-IgM)-positive sera, 5 sera from hypertensive patients, 5 sera from diabetes mellitus patients, and 14 sera from novel coronavirus infection disease 19 (COVID-19) patients. The interference factors causing false-positive reactivity with the two methods were analyzed, and the urea dissociation test was employed to dissociate the SARS-CoV-2 IgM-positive serum using the best dissociation concentration. The two methods detected positive SARS-CoV-2 IgM in 22 mid-to-high-level-RF-IgM-positive sera and 14 sera from COVID-19 patients; the other 50 sera were negative. At a urea dissociation concentration of 6 mol/liter, SARS-CoV-2 IgM results were positive in 1 mid-to-high-level-RF-IgM-positive serum and in 14 COVID-19 patient sera detected using GICA. At a urea dissociation concentration of 4 mol/liter and with affinity index (AI) levels lower than 0.371 set to negative, SARS-CoV-2 IgM results were positive in 3 mid-to-high-level-RF-IgM-positive sera and in 14 COVID-19 patient sera detected using ELISA. The presence of RF-IgM at mid-to-high levels could lead to false-positive reactivity of SARS-CoV-2 IgM detected using GICA and ELISA, and urea dissociation tests would be helpful in reducing SARS-CoV-2 IgM false-positive results.