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2020

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03

Scientific Research News | Research Progress of novel coronavirus Pneumonia (COVID-19) (39)


1. Progress in COVID-19 biology research

■ On March 3, at a press conference held by the joint prevention and control mechanism of the State Council, Mi Feng, spokesperson of the National Health Commission and deputy director of the Department of Publicity, said: 12 new confirmed cases in Wuhan have dropped to single digits; In Hubei except Wuhan, all prefectures and cities have had no new confirmed cases for one consecutive week; In provinces other than Hubei, there were 8 new confirmed cases, of which 1 were imported cases. The above information suggests that, on the whole, the peak of the current round of epidemic in China has passed, the number of new cases is continuing to decline, and the epidemic has generally remained at a low level. It is necessary to put medical treatment work in the first place, not to be paralyzed, not tired of war, not to slacken, and not to relax and grasp all prevention and control work.

■ On March 3, at the regular press conference on epidemic prevention and control in Guangdong Province, Academician Zhong Nanshan said that the end of the epidemic in June can be expected. In general, coronaviruses are less active in the summer when temperatures are higher, but the end of the epidemic also depends on the importance of each country. If some countries do not pay attention to the harm and contagion of the epidemic, it is difficult to say the end time. In addition, for the problem that some patients tested positive, Zhong Nanshan said that in a Hong Kong study, the residual nucleic acid fragments of the new coronavirus that may have been detected from Fuyang patients were detected, and no live virus was detected. Therefore, based on the current data, no Fuyang patients have been found to be contagious.

2. Progress in COVID-19 biology research

■ On March 3, Tan Wenjie, Institute of Viral Disease Prevention and Control, Chinese Center for Disease Control and Prevention, published a research paper entitled "Detection of SARS-CoV-11 in Different Types of Clinical Specimens" online in JAMA, which observed the biological distribution of the novel coronavirus between different tissues hospitalized in patients with COVID-2. The patients were diagnosed based on symptoms and radiology and confirmed by testing for the novel coronavirus, and the study was approved by the ethics committees of the participating hospitals. The study found that the novel coronavirus was detected in specimens from multiple sites in 19 COVID-205 patients, with lower respiratory tract samples most commonly detected with the virus. Importantly, live virus was detected in feces, suggesting that the novel coronavirus may be spreading via the fecal route. A small percentage of blood samples have a positive PCR test, suggesting that the infection may sometimes be systemic. Transmission of the virus through respiratory and extrarespiratory pathways may help explain the rapid spread of the disease [19].

■ On March 3, a paper entitled "Serological Test is an Efficient Supplement of RNA Detection for Confirmation of SARS-CoV-11 Infection" was published on Preprints, which showed that viral RNA detection combined with serological testing can improve diagnostic sensitivity while maintaining high specificity. Novel coronavirus-specific serum testing is of great value to clinical practice and public health. The researchers used chemiluminescence, enzyme-linked immunosorbent assay (ELISA), colloidal gold to detect serum total antibody (Ab) and immunoglobulin (IgM) antibodies. The results showed that all three methods had higher sensitivity and specificity for total Ab and IgM detection, and higher sensitivity for Ab detection compared to IgM. The results show that the combined application of RNA and Ab tests can improve diagnostic sensitivity while maintaining high specificity, which is considered to be of great value to clinical practice and public health. In general, the detection of Ab by ELISA method and chemiluminescence method has the characteristics of convenient sampling, high throughput, high efficiency, quantifiability or semi-quantification, and colloidal gold method is a real-time and focused detection method. These antibody assays should be used as an effective complement to RNA testing in different settings to improve diagnostic sensitivity and specificity [2].

■ On March 3, researchers from the University of Melbourne and other institutions in Australia published a paper entitled "Direct RNA sequencing and early evolution of SARS-CoV-8" on the preprint platform bioRxiv. The researchers provided direct RNA sequences of the novel coronavirus, described the mRNA structure of the coronavirus's subgenome length, and described information about the evolutionary genetics of the coronavirus revealed from the shared data. The study used a recently established direct RNA sequencing method based on highly parallel nanopore arrays by which novel coronavirus samples generated 2 readouts containing 40Mb of sequence information during 680347 hours of sequencing. Consistent with the genomes of cultured novel coronavirus isolates, some of the readings belonged to coronavirus sequences (860.28%), including 9Mb sequences distributed across 29893,367 base genomes. Some of them are more than 2,42 bases long, and the researchers also captured most of the genome on a single molecule. Through data analysis, they identified 5 sites with predictable 3-methylcytosine modifications that present consistent positions across subgenomic length mRNAs. In other positive single-stranded viruses, RNA methylation changes dynamically during infection, affecting host-pathogen interactions and viral replication. Once the dataset is available for direct RNA sequences of the novel coronavirus, researchers may find other modifications that are currently poorly understood. In summary, the researchers believe that by using direct RNA sequence data, it contributes to an in-depth understanding of the molecular biology of novel coronaviruses and may help construct a detailed view of the length mRNA structure of viral subgenomes [<>].

3. Progress in pharmacological research on COVID-19

■ A "clinical study on the safety and efficacy of favipiravir in the treatment of novel coronavirus pneumonia (COVID-19) patients" completed by the National Engineering Research Center for Emergency Prevention and Control Drug Engineering Technology and the team of Liu Lei and Liu Yingxia of Shenzhen Third People's Hospital has obtained preliminary clinical results (registration number: ChiCTR2000029600). Studies have shown that Favipiravir may alleviate the progression of novel coronavirus pneumonia by accelerating viral clearance, and the results have been submitted to the Chinese Academy of Engineering. A total of 80 patients were enrolled in this clinical trial, 35 in the favipiravir treatment group, and the control group was 45 new coronary pneumonia patients matched to the age, sex and disease severity of the treatment group, receiving lopinavir/ritonavir tablets. The median drug-to-viral clearance time, chest imaging improvement rate and safety on day 14 of treatment were compared between the two groups. The results showed that in terms of viral clearance, the median time of viral clearance (viral nucleic acid to negative) in the favipiravir experimental group after treatment was significantly shorter than that in the control group, 4 days and 11 days, respectively. In terms of another key indicator, the improvement of chest imaging of patients, the improvement rates of the treatment group compared with the control group were 91.43% and 62.22%, respectively. At the same time, the favipiravir treatment group had fewer adverse effects and was better tolerated than in the control group. All baseline characteristics were comparable in both groups.

4. COVID-19 epidemiological studies

■ On March 2020, 3, Lan Ke, Liu Yingle of Wuhan University, Sun Ziyong of Huazhong University of Science and Technology and Hongjie Yu of Fudan University jointly published a research paper entitled "Detection of Covid-12 in Children in Early January 19 in Wuhan, China" online in the top international medical journal NEJM. A total of 2020 hospitalized children (≤ 2020 years of age) were studied retrospectively. Among 1 children, the most common causative agents were influenza A virus (7 cases [1.15%]) and influenza B virus (366 cases [16.366%]). The novel coronavirus, the virus that causes Covid-23, was detected in 6 patients (3.20%). The study obtained informed consent from parents or guardians of Covid-5 patients to publish their clinical data. Six patients with Covid-5 had onset dates between 6 January and 1 January 6 and the patient was hospitalized between 19 January and 19 January. The results of this study show that Covid-6 occurred in these patients and children in the early stages of the novel coronavirus outbreak, caused moderate to severe respiratory illness, and was associated with ICU admission to one patient, and neither the children nor their family members had direct contact with the Huanan Seafood Wholesale Market or each other [19].

■ On March 2020, 3, Oon-Tek Ng et al. of Singapore's National Centre for Infectious Diseases published a research paper entitled "SARS-CoV-12 Infection among Travelers Returning from Wuhan, China" online in the top international medical journal NEJM, which tracked 2 people who boarded a flight from Wuhan to Singapore on January 2020, 1.

Temperature checks at boarding and before boarding prevented 3 cases of hyperthermia from boarding. Upon arrival in Singapore, a temperature check (fever defined as a body temperature ≥38°C) was performed and 2 people (a 48-year-old female [Patient 1] and a 47-year-old female [Patient 2]) were found to have a fever. Two febrile women were immediately taken to hospital and tested positive for the novel coronavirus. The remaining 2 febrile travelers, aged between 92 and 2, were quarantined for 82 days at government quarantine facilities, where they were tested for symptoms and fever three times a day. Six patients reported symptoms and all six tested negative for the novel coronavirus. On the 14rd day of quarantine, samples were taken from 6 of the 3 asymptomatic people (86 nasopharyngeal swab samples and 76 nasal swab sample) and tested by PCR analysis. A 75-year-old boy (son of patient 1) tested positive for Covid-17 and continued to be PCR positive for 1 weeks, while a 19-year-old man was inconclusive (negative for N gene and ORF2ab gene). On the 41th day of quarantine, samples were taken from all 1 asymptomatic people who were quarantined (6 nasopharyngeal swab samples and 87 nasal swab samples, all tested negative). On Day 85, all those who were not isolated in hospital were quarantined and none of the patients were infected with Covid-2. Understanding the significance of the spread of novel coronavirus infection from asymptomatic or mildly symptomatic Covid-14 cases is critical to developing containment strategies [19].

 

Bibliography:

[1] W. Wang, Y. Xu, R. Gao, et al. Detection of SARS-CoV-2 in Different Types

of Clinical Specimens. JAMA 2020.

[2] Xia, N.; Wang, G.; Gong, W. Serological Test is an Efficient Supplement of RNA Detection for Confirmation of SARS-CoV-2 Infection. Preprints 2020, 2020030184.

[3] Taiaroa G, Rawlinson D, Featherstone L, et al. Direct RNA sequencing and early evolution of SARS-CoV-2. bioRxiv 2020:2020.03.05.976167.

[4] Liu W, Zhang Q, Chen J, et al. Detection of Covid-19 in Children in Early January 2020 in Wuhan, China. New England Journal of Medicine 2020.

[5] Ng O-T, Marimuthu K, Chia P-Y, et al. SARS-CoV-2 Infection among Travelers Returning from Wuhan, China. New England Journal of Medicine 2020.

 

Feed | Pingshan Biomedical R&D and Transformation Center, Scientific Research Department

Source | People's Daily, Translational Medicine Network, iNature, Science Network, Global Science

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