ABSTRACT
Background: No study has revealed spatial transmission characteristics of COVID-19 in Wuhan, China. We aimed to analyze the spatiotemporal spread of COVID-19 in Wuhan and its influence factors.Methods: Information of 32,682 COVID-19 cases reported through March 18 were extracted from the national infectious disease surveillance system. Geographic information system methods were applied to analysis transmission of COVID-19 and its influence factors in different periods.Results: We found decrease in effective reproduction number (Rt) and COVID-19 related indicators through taking a series of effective public health measures including restricting traffic, centralized quarantine and strict stay-at home policy. The distribution of COVID-19 cases number in Wuhan showed an obvious global aggregation and a local aggregation in central urban areas, but such aggregations was decreased in the later period of the epidemic. In addition, the analysis at streets-level suggested population density and the number of hospitals were influence factors of spatial difference.Conclusions: The epidemic situation showed obvious global and local spatial aggregations. High population density and directional flow of the Population to hospitals may account for the aggregations. Strong quarantine measures and restrictions on movement of residents in Wuhan make the epidemic under control in a short time.
Subject(s)
COVID-19 , Communicable DiseasesABSTRACT
Background: Contact tracing with quarantine of SARS-CoV-2 positive contacts is required on an unprecedented scale worldwide.Methods: During February 1-March 25, 2020, COVID-19 cases in Hubei province were traced by more than 1800 teams. PCR positive contacts without COVID-19 symptoms with two or more consecutive positive tests for SARS-CoV-2 were categorized as: (a) asymptomatic SARS-CoV-2 if without COVID-19 symptoms throughout the > 14 days of quarantine, (b) pre-symptomatic SARS-CoV-2 if COVID-19 symptoms started during the quarantine, and (c) false positive contacts if two consecutive follow-up qRT-PCRs were negative after an initial positive SARS-CoV-2 test.Findings: 48,944 COVID-19 patients identified 277,066 contacts who were tested for SARS-CoV-2; upon ascertainment, 3,152 contacts without symptoms were SARS-CoV-2 PCR positive without symptoms, and 50 contacts were false positives. After quarantine, 2928 were classified as asymptomatic and 174 were pre-symptomatic SARS-CoV-2 contacts, with a pre-symptomatic case fatality (11/174) of 6.3%. The average interval between the initial SARS-CoV-2 PCR positive and onset of COVID-19 symptoms was 9.7 days, and the average time from onset of symptoms to death for deceased pre-symptomatic cases was 6.3 days (range = 1 - 35 days).Interpretation: Contact tracing of COVID-19 cases required many contact tracing teams, testing all contacts without COVID-19 symptoms, and quarantine of asymptomatic SARS-CoV-2 positive contacts. Countries with limited contact tracing, testing and quarantine of asymptomatic SARS-CoV-2 infected contacts under-estimate the number of infected asymptomatic SARS-CoV-2 contacts, and their contribution to COVID-19 spread.Funding Statement: National Natural Science Foundation of China (82041021), Bill & Melinda Gates Foundation (INV-006371).Declaration of Interests: The authors declare they have no conflict of interest.Ethics Approval Statement: This study was approved by the Medical Research Ethics Review Committee of Sun Yat-sen University School of Public Health (No.: 2020016). Consistent with public health regulations the informed consent was waived because data were collected as part of public health practice associated with the COVID-19 outbreak investigation and response.
Subject(s)
COVID-19ABSTRACT
Background: The coronavirus disease 2019 (Covid-19) spreads rapidly around the world. Objective: To evaluate the association between comorbidities and the risk of death in patients with COVID-19, and to further explore potential sex-specific differences. Methods: We analyzed the data from 18,465 laboratory-confirmed cases that completed an epidemiological investigation in Hubei Province as of February 27, 2020. Information on death was obtained from the Infectious Disease Information System. The Cox proportional hazards model was used to estimate the association between comorbidities and the risk of death in patients with COVID-19. Results: The median age for COVID-19 patients was 50.5 years. 8828(47.81%) patients were females. Severe cases accounted for 20.11% of the study population. As of March 7, 2020, a total of 919 cases deceased from COVID-19 for a fatality rate of 4.98%. Hypertension (13.87%), diabetes (5.53%), and cardiovascular and cerebrovascular diseases CBVDs (4.45%) were the most prevalent comorbidities, and 27.37% of patients with COVID-19 reported having at least one comorbidity. After adjustment for age, gender, address, and clinical severity, patients with hypertension (HR 1.55, 95%CI 1.35-1.78), diabetes (HR 1.35, 95%CI 1.13-1.62), CBVDs (HR 1.70, 95%CI 1.43-2.02), chronic kidney diseases (HR 2.09, 95%CI 1.47-2.98), and at least two comorbidities (HR 1.84, 95%CI 1.55-2.18) had significant increased risks of death. And the association between diabetes and the risk of death from COVID-19 was prominent in women (HR 1.69, 95%CI 1.27-2.25) than in men (HR 1.16, 95%CI 0.91-1.46) (P for interaction = 0.036). Conclusion: Among laboratory-confirmed cases of COVID-19 in Hubei province, China, patients with hypertension, diabetes, CBVDs, chronic kidney diseases were significantly associated with increased risk of death. The association between diabetes and the risk of death tended to be stronger in women than in men. Clinicians should increase their awareness of the increased risk of death in COVID-19 patients with comorbidities.