[Epidemiological characteristics of imported COVID-19 cases in Tianjin].

Objective: To understand the epidemiological characteristics of imported COVID-19 cases in Tianjin, and provide references for risk assessment and control of imported COVID-19 cases. Methods: The information of imported COVID-19 cases were obtained from National Notifiable Disease Report System of China CDC. The data of imported COVID-19 cases reported from Tianjin airport and epidemiological surveys by CDCs at all levels from March 15, 2020 to August 31, 2021 were collected and analyzed by using software Excel 2010, SPSS 25.0 and R. Results: From March 15, 2020 to August 31, 2021, a total of 606 imported cases of COVID-19 were reported in Tianjin, in which 552 cases were finally included in the analysis. The male to female ratio of the cases was 1.8∶1, the age of the cases ranged from 3 to 77 years, and the cases were mainly reported in age group 20-39 years (59.8%). The areas where the imported case sojourned within 14 days included Europe (242 cases, 43.8%), Africa (139 cases, 25.2%), Americas (85 cases, 15.4%) and Asia (86 cases, 15.6%). The proportion of confirmed cases in autumn and winter was relatively high. During the study period, the proportion of infected persons found in custom entry quarantine decreased, and the proportion of persons with personal health declaration and under medical isolation observation increased. The interval between entry and diagnosis of infected persons tended to increase. Conclusion: The proportion of imported COVID-19 cases detected on the first day of entry at Tianjin airport decreased, and the interval to detect the infected persons trended to increase, to which close attention must be paid.

[Analysis of selective endoscopy results during the epidemic of coronavirus disease 2019 (COVID-19)].

Objective: To explore the necessity and safety of selective endoscopy to detect gastrointestinal (GI) malignancy during the outbreak of coronavirus disease 2019 (COVID-19). Methods: A retrospective cohort study was carried out to analyze the clinical data of selective endoscopy performed at the Endoscopic Center, Zhongshan Hospital of Fudan University from February 20 to March 6, 2020. Clinical data included epidemiological questionnaire, chief complaints, endoscopic findings and biopsy pathology results, etc. All medical staff had blood test for IgM/IgG antibodies of COVID-19. Patients and their families were followed up by phone to determine whether they were infected with COVID-19. Meanwhile, the clinical data of selective endoscopy during the same period from February 20 to March 6, 2019 were collected as the control group to compare the overall results of endoscopy examinations during the epidemic and the detection rate of GI malignancy. Results: A total of 911 patients underwent endoscopy in the epidemic period group, and a total of 5746 cases in the control group, which was 6.3 times over the epidemic period group. In the epidemic period group, 544 cases received gastroscopy and 367 cases received colonoscopy, while 3433 cases received gastroscopy and 2313 cases received colonoscopy in the control group, which were both 6.3 times of epidemic period group. Gastroscopy revealed that 39 patients (7.2%) were diagnosed with upper GI malignancies in the epidemic period group and 77 patients (2.2%) in the control group with significant difference (χ(2)=40.243, P<0.001). The detection rate of gastric cancer in these two groups was 3.3% (n=18) and 1.7% (n=59) respectively with significant difference (χ(2)=6.254,P=0.012). The detection rate of esophageal cancer was 3.7% (n=20) and 0.5% (n=18) respectively with significant difference (χ(2)=49.303,P<0.001). Colonoscopy revealed that colorectal cancer was found in 32 cases (8.7%) of the epidemic period group and 88 cases (3.8%) of the control group with significant difference (χ(2)=17.888, P<0.001). During the epidemic period, no infection of medical staff was found through the blood test of IgM/IgG antibodies on COVID-19. No patient and family members were infected with COVID-19 by phone follow-up. Conclusion: Compared with the same period in 2019, the number of selective endoscopy decreases sharply during the epidemic period, while the detection rate of various GI malignant tumors increases significantly, which indicates that patients with high-risk symptoms of GI malignancies should still receive endoscopy as soon as possible. Provided strict adherence to the epidemic prevention standards formulated by the state and professional societies, it is necessary to carry out clinical diagnosis and treatment as soon as possible.

[Analysis on cluster cases of COVID-19 in Tianjin].

Objective: To understand the characteristics of clusters of COVID-19 cases in Tianjin, and provide epidemiological evidence for the prevention and control of COVID-19. Methods: The data of all the COVID-19 cluster cases in Tianjin, reported by 22 February 2020, were collected to analyze the characteristics of different types of the clusters. Results: A total of 115 COVID-19 cases were reported in 33 clusters in Tianjin included 28 family clusters (71 cases), 1 work place cluster (10 cases), 3 transport vehicle clusters (8 cases) and 1 public place cluster (26 cases). Family clusters were caused by the cases from the working place or public place clusters. Numbers of secondary cases of family clusters was between 1 to 7, the median number was 2. The interval from onset to diagnosis for the first case was longer than those of other cases in the familial clusters (Z=-2.406, P=0.016). The median of incubation period of the public place clusters was 2 days. The intervals from onset to diagnosis were significant different among the family, working place and public place clusters (H=8.843, P=0.012), and also significant differences in onset time among the secondary cases (H=16.607, P=0.000). Conclusions: In the surveillance of COVID-19 epidemic, special attention should be paid to places where clustering are prone to occur, and the epidemiological investigation should be carried out timely to confirm the cluster. To prevent the transmission of COVID-19, the close contacts of the patients should be transferred to an assigned observation place on time for single room isolation. The awareness of COVID-19 prevention is low in some rural areas, reflected by many mass gathering activities and delayed medical care seeking after onset. It is necessary to strengthen the health education and take control measures in early period of epidemic.

[Epidemiological characteristics of confirmed COVID-19 cases in Tianjin].

Objective: To investigate the clinical and epidemiological characteristics of 135 confirmed cases of COVID-19 in Tianjin. Methods: The clinical and epidemiological data of 135 cases of COVID-19 in Tianjin were collected, and the data were analyzed with descriptive method. The factors influencing the severity of the illness were analyzed. Results: Among the 135 COVID-19 cases, 72 were males and 63 were females, the age of the cases was (48.62±16.83) years, and the case fatality rate was 2.22%. Local transmission caused 74.81% of the cases. A total of 33 clusters occurred, involving 85.92% of all COVID-19 cases. The median of the incubation period of COVID-19 was 6.50 days, the average generation interval was 5 days, and the household secondary transmission rate was 20.46%. Fever was the main symptom (78.63%), followed by cough (56.48%). Multivariate regression analysis indicated that age (OR=1.038, 95%CI: 1.010-1.167) and the number of chronic underlying diseases (OR=1.709, 95%CI: 1.052-2.777) were the risk factors of severe illness. Conclusions: Fever was the main symptom at the early phase of COVID-19 in Tianjin, and the local cluster cases accounted for high proportion in confirmed COVID-19 cases reported in Tianjin. Severe illness was prone to occur in people with old age and multi underlying diseases. Strict isolation of close contacts and intensive care of high-risk groups are the main measures to reduce the morbidity and case fatality of COVID-19.