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Objective:To analyze the genome characteristics and variations in nucleotides and amino acids of SARS-CoV-2 causing an outbreak in Henan Province in November 2021 and perform the traceability analysis.Methods:In this study, throat swab specimens from cases in the acute phase were collected and tested for the nucleic acids of SARS-CoV-2 by real-time fluorescent RT-PCR. SARS-CoV-2 nucleic acid-positive samples were subjected to high-throughput genome sequencing and whole-genome alignment analysis.Results:The median Ct values of ORF1ab gene and N gene in 70 positive specimens was 26.41 (15.58 to 39.27) and 24.43 (12.04 to 39.74), respectively. Compared with the sequence of Wuhan-Hu(NC_045512) reference strain, 47 to 49 nucleotide mutations sharing 47 nucleotide mutation and 41 amino acid mutations were found in 63 strains of successfully sequenced SARS-CoV-2. Nine nucleotide mutations and 12 amino acid mutations were found in the spike protein. The index case shared 47 mutations with the Russian imported cases in Henan Province on October 14 and the local cases in Jiangxi Province in October. Moreover, their genomes were highly homologous and they all belonged to the Delta variant (AY.122 evolutionary branch).Conclusions:Continuous monitoring of imported COVID-19 cases and prolonging the period of quarantine were needed to reduce the risk of local outbreak and epidemic caused by imported COVID-19 cases. Analysis of the genomic characteristics of SARS-CoV-2 and the variations in nucleotides and amino acids was conducive to trace the origin of COVID-19 outbreak quickly and provide reference for precise control.
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Objective:To monitor the changes in specific IgM and IgG antibodies in patients diagnosed with COVID-19 after SARS-CoV-2 infection, and analyze their clinical significance.Methods:A total of 168 serum samples were collected from 56 COVID-19 patients with different disease courses who were positive for nucleic acid test at Henan Center for Disease Control and Prevention on January 8, 2020 and February 21, 2020. Serum samples from 25 healthy people excluded from COVID-19 were used as control group. IgM and IgG antibodies against SARS-CoV-2 were detected by chemiluminescence method.Results:IgM antibody increased sharply in 1-3 weeks after onset, and reached the peak value (21.78 AU/ml) in the 3rd week after onset. IgG antibody increased the most in 3-6 weeks after onset, and reached the peak value (81.58 AU/ml) in the 9th week after onset. The levels of IgM and IgG antibodies were closely correlated with age and disease course ( P<0.05). The antibody level of 30-60 years old group was the highest, the IgM antibody positive rate and antibody level of acute stage and previous infection were lower than that of recovery stage, and the IgG antibody positive rate and antibody level of acute stage were lower than that of recovery stage and previous infection. During the whole course of the disease, the levels of IgM and IgG antibodies increased gradually in the acute stage, reached the peak in the recovery stage, and decreased and maintained at a certain level in the past infection. Conclusions:Serum SARS-CoV-2 IgM and IgG antibody detection can be used as auxiliary diagnostic indicators for COVID-19, and its continuous observation is helpful for epidemiological investigation, serological diagnosis and disease course monitoring.
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Objective:To analyze the evolutionary characteristics and variations of 2019 novel coronavirus (2019-nCoV) strains imported from abroad in Henan Province.Methods:A total of 16 imported cases of coronavirus disease 2019 (COVID-19) reported in Henan Province from May to December 2020 were enrolled. The throat swab specimens from the patients were collected and sent to the Henan Provincial Center for Disease Control and Prevention for whole genome sequencing. Taking SARS-CoV-2 Wuhan-Hu-1 published in Global Initiative on Sharing All Influenza Data (GISAID) as the reference sequence, the sequences were aligned and analyzed by MEGA X, and the phylogenetic tree was constructed by the maximum likelihood method.Results:Among 16 cases, 13 cases were imported from Russia, two cases were imported from Myanmar, and one case was imported from Ukraine. A total of 16 strains of 2019-nCoV genomes with the lengths of 29 804 bp to 29 882 bp were obtained. A total of 145 nucleotide mutations and 80 amino acid mutations were detected. Nucleotide variations of C241T, C3037T, C14408T, A23403G and the amino acid variation of D614G in spike protein were detected in all sequences. Meanwhile, insertion A at the site of 29704 was found in BetaCov/HEN02/Human/2020, BetaCov/HEN04/Human/2020 and BetaCov/HEN05/Human/2020. Deletion variation was not found. Phylogenetic analysis showed that there was no correlation between the 16 strains and currently epidemic variants of concern (VOC) .Conclusion:From May to December 2020, the detection of viral genome mutations in the imported cases of Henan Province shows randomness and diversity, while the strains are not VOC.