关键词: 新型冠状病毒肺炎, 新冠肺炎, 新型冠状病毒, 境外输入, 循环阈值, 临床特征

Abstract: Background　Under the increasingly severe situation of COVID-19 pandemic，Hebei Province has received a large number of individuals returned from abroad.Therefore，on the occasion of returning to work，production and school，it is imperative to effectively strengthen SARS-CoV-2 screening and management of overseas imported cases and to take actions to cut off the transmission channels to prevent the spread of SARS-CoV-2 from this group.Objective　To study the clinical characteristics of overseas imported and local COVID-19 cases in Hebei Province，to provide a reference for developing targeted programs to prevent the recurrence of the pandemic.Methods　28 patients with COVID-19（7 overseas imported and 21 local ）who were admitted to Shijiazhuang Fifth Hospital from January 21 to April 5，2020 were selected.The epidemiological characteristics，clinical manifestations，laboratory and imaging examinations of them were summarized and analyzed.Results　（1）The imported group included 5 men and 2 women，mostly were young adults〔4（57.1%）were 19-29 years〕，with an average age of （23.6±11.1） years.The local group included 14 men and 7 women，mostly were middle-aged and elderly adults〔19（90.5%）aged 30-72 years〕，with an average age of（43.6±19.7） years，mainly were infected with COVID-19 after family gatherings.（2）Among the imported cases，1 had fever，1 had diarrhea，and 5 had no clinical symptoms；6（85.7%）had common type COVID-19，1（14.3%）had severe type，no mild and critically severe types.Among the local cases，15 had fever，9 had cough，5 had sore throat，3 had fatigue，2 had muscle pain，and 1 had diarrhea；1（4.8%） had mild type COVID-19，15（71.4%）had common type，4（19.0%）had severe type，and 1（4.8%）had critically severe type.（3）The imported cases showed lower average cycle threshold（Ct） value of SARS-CoV-2 N gene（t=14.430，P<0.001） than the local cases.Moreover，the average Ct value of SARS-CoV-2 N gene and ORF1ab gene was also lower in the imported cases（t=17.856，P<0.001）.The prevalence of reduced CD4+ T lymphocytes was above 50.0% in both groups compared with the normal reference range value.The prevalence of reduced lymphocyte count and CD3+ T lymphocytes，and elevated C-reactive protein，aspartate aminotransferase，alanine aminotransferase and lactate dehydrogenase was higher than 40.0% in the imported cases.The prevalence of elevated C-reactive protein and lactate dehydrogenase was higher than 40.0% in the local cases.（4）The lung CT examination of two groups indicated that the lesions were mainly distributed in bilateral lung lobes，followed by unilateral unilobe，and then unilateral multiple lobes.Ground-glass opacity was the main image finding in the imported group，while ground-glass opacity and consolidation opacity were the main image findings in the local group.Conclusion　In Hebei Province，the imported COVID-19 cases showed milder symptoms，lower Ct values of SARS-CoV-2 N gene and ORF1ab gene and higher SARS-CoV-2 viral nucleic acids from nasopharyngeal swabs，which indicate that the virus from imported cases may be more contagious.Therefore，it is necessary to strengthen isolation，screening and early diagnosis of imported cases，so as to prevent the spread of disease as much as possible.

Key words: Corona Virus Disease 2019, COVID-19, SARS-CoV-2, Imported from abroad, Cycle threshold value, Clinical characteristics