scholarly journals Clinical Characteristics of 24 Asymptomatic Infections with COVID-19 Screened among Close Contacts in Nanjing, China

2020 ◽  
Author(s):  
Zhiliang Hu ◽  
Ci Song ◽  
Chuanjun Xu ◽  
Guangfu Jin ◽  
Yaling Chen ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Clinical Characteristics ◽  
Close Contact ◽  
Contact Tracing ◽  
Severe Illness ◽  
Asymptomatic Carriers ◽  
Asymptomatic Infections ◽  
Clinical Records ◽  
Close Contacts ◽  
Nucleic Acid Tests

AbstractBackgroundPrevious studies have showed clinical characteristics of patients with the 2019 novel coronavirus disease (COVID-19) and the evidence of person-to-person transmission. Limited data are available for asymptomatic infections. This study aims to present the clinical characteristics of 24 cases with asymptomatic infection screened from close contacts and to show the transmission potential of asymptomatic COVID-19 virus carriers.MethodsEpidemiological investigations were conducted among all close contacts of COVID-19 patients (or suspected patients) in Nanjing, Jiangsu Province, China, from Jan 28 to Feb 9, 2020, both in clinic and in community. Asymptomatic carriers were laboratory-confirmed positive for the COVID-19 virus by testing the nucleic acid of the pharyngeal swab samples. Their clinical records, laboratory assessments, and chest CT scans were reviewed.FindingsNone of the 24 asymptomatic cases presented any obvious symptoms before nucleic acid screening. Five cases (20.8%) developed symptoms (fever, cough, fatigue, etc.) during hospitalization. Twelve (50.0%) cases showed typical CT images of ground-glass chest and 5 (20.8%) presented stripe shadowing in the lungs. The remaining 7 (29.2%) cases showed normal CT image and had no symptoms during hospitalization. These 7 cases were younger (median age: 14.0 years; P = 0.012) than the rest. None of the 24 cases developed severe COVID-19 pneumonia or died. The median communicable period, defined as the interval from the first day of positive nucleic acid tests to the first day of continuous negative tests, was 9.5 days (up to 21 days among the 24 asymptomatic cases). Through epidemiological investigation, we observed a typical asymptomatic transmission to the cohabiting family members, which even caused severe COVID-19 pneumonia.InterpretationThe asymptomatic carriers identified from close contacts were prone to be mildly ill during hospitalization. However, the communicable period could be up to three weeks and the communicated patients could develop severe illness. These results highlighted the importance of close contact tracing and longitudinally surveillance via virus nucleic acid tests. Further isolation recommendation and continuous nucleic acid tests may also be recommended to the patients discharged.

scholarly journals Efficacy and Safety of Lianhuaqingwen Capsules for the Prevention of Coronavirus Disease 2019: A Prospective Open-Label Controlled Trial

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiaowei Gong ◽  
Boyun Yuan ◽  
Yadong Yuan ◽  
Fengju Li
Keyword(s):  
Nucleic Acid ◽  
Treatment Group ◽  
Close Contact ◽  
Controlled Trial ◽  
Control Group ◽  
Open Label ◽  
Medical Observation ◽  
Observation Period ◽  
Close Contacts ◽  
Nucleic Acid Tests

Coronavirus disease 2019 (COVID-19) has become a global pandemic. Community and close contact exposures continue to drive the COVID-19 pandemic. There is no confirmed effective treatment for suspected cases and close contacts. Lianhuaqingwen (LH) capsules, a repurposed Chinese herbal product that is currently on the market, have proven effective for influenza and COVID-19. To determine the safety and efficacy of LH capsules for the prevention of COVID-19, we conducted a prospective open-label controlled trial of LH capsules on subjects who had close contact with people infected with COVID-19. Subjects received LH capsules (4 capsules, three times daily) or the usual medical observation for 14 days. The primary endpoint was the rate of positive nucleic acid tests of nasal and pharyngeal swabs during the quarantine medical observation period. We included 1976 patients, including 1101 in the treatment group and 875 in the control group. The rate of positive nucleic acid tests in the treatment group was significantly lower than that in the control group (0.27% vs. 1.14%, respectively; mean difference: −0.87%; 95% CI: −1.83 to −0.13; p = 0.0174 ) during the quarantine medical observation period (14 days). Among subjects with different close contact states, there was no significant difference in the rate of positive nucleic acid test results among close contacts in the treatment group and the control group (6.45% vs. 11.43%, respectively; p = 0.6762 ). Among secondary close contacts, the rate of positive nucleic acid tests in the treatment group was significantly lower than that in the control group (0.09% vs. 0.71%, respectively; p = 0.0485 ). No serious adverse events were reported. Taken together, and in light of the safety and effectiveness profiles, these results show that LH capsules can be considered to prevent the progression of COVID-19 after close contact with an infected person. This trial is registered with ChiCTR2100043012.

scholarly journals The Positive Rate of Nucleic Acid Testing and the Epidemiological Characteristics of COVID-19 in Chongqing

2022 ◽  
Vol 8 ◽  
Author(s):  
Xiaohua Liang ◽  
Yajun Sun ◽  
Lun Xiao ◽  
YanLing Ren ◽  
Xian Tang
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acid Testing ◽  
Asymptomatic Carriers ◽  
First Case ◽  
Latency Range ◽  
Increased Risk ◽  
Positive Rate ◽  
Epidemiological Characteristics ◽  
Close Contacts ◽  
Nucleic Acid Tests

ObjectiveThe purpose of this study is to analyze the positive rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid testing (NAT), cases of and deaths due to SARS-CoV-2, and the epidemiological characteristics of SARS-CoV-2 to identify high-risk populations.MethodsA retrospective study in Jiulongpo district of Chongqing was conducted by performing continuous observations of the frequency of SARS-CoV-2 NAT, analyzing the data of close contacts of patients and asymptomatic carriers, and collecting epidemiological data. Data were collected from January 20, 2020, when the first case of SARS-CoV-2 infection was reported, to March 26, 2020. Descriptive statistical analysis and Cochrane–Mantel–Haenszel analysis were used to compare the positive detection rates and positive diagnostic rates of different exposure groups.ResultsA total of 7,118 people received 10,377 SARS-CoV-2 nucleic acid tests in one district, and the SARS-CoV-2 positive rates were 0.40% (18/4446) and 0.15% (4/2672) in people receiving one and ≥ two nucleic acid tests (p = 0.06), respectively. Those with suspected cases (12.35%) and close contacts (8%) had higher positive rates than people tested at fever clinics (0.39%) (p < 0.001). The median latency (range) of cases was 5 (2, 9) days, and the median time from diagnosis to recovery was 22 (14, 25) days. One recovered patient received a positive test result at 28 days after recovery when she attempted to donate blood. Six clustered cases, including one patient who died, indicated persistent human-to-human transmission. One patient who was diagnosed after death was found to have infected 13 close contacts. People working in catering and other public service departments (36.36%) and people who are unemployed and retirees (45.45%) have an increased risk of infection compared with technical staff (9.09%) and farmers (9.09%).ConclusionThe total positive rate was low in the tested population, and more effective detection ranges should be defined to improve precise and differentiated epidemic control strategies. Moreover, in asymptomatic carriers, SARS-CoV-2 tests were positive after recovery, and patients with suspected SARS-CoV-2 infection who die may pose serious potential transmission threats.

scholarly journals A considerable proportion of individuals with asymptomatic SARS-CoV-2 infection in Tibetan population

2020 ◽  
Author(s):  
Huan Song ◽  
Jun Xiao ◽  
Jiajun Qiu ◽  
Jin Yin ◽  
Huazhen Yang ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Clinical Characteristics ◽  
Close Contact ◽  
Descriptive Study ◽  
Han Chinese ◽  
Considerable Proportion ◽  
Initial Symptom ◽  
Asymptomatic Carriers ◽  
Tibetan Population ◽  
Asymptomatic Individuals

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) quickly became a major epidemic threat in the whole China. We analysed SARS-Cov-2 infected cases from Tibetan Autonomous Prefecture, and noted divergent characteristics of these Tibetans infected cases compared to Han Chinese, characterizing by a considerable proportion of asymptomatic carriers (21.7%), and few symptomatic patients with initial symptom of fever (7.7%). Here, we did a descriptive study on clinical characteristics of 18 asymptomatic individuals with SARS-CoV-2 infection. The median age of these asymptomatic carriers was 31 years and one third of them were students, aged under 20 years. Notably, some of asymptomatic carriers had recognizable changes in radiological and laboratory indexes. Our finding indicates a potentially big number of SARS-CoV-2 asymptomatic carriers in prevalent area, highlighting a necessity of screening individuals with close contact of infected patients, for a better control on the spread of SARS-CoV-2 infection.

scholarly journals Salivary detection of COVID-19. Clinical performance of oral sponge sampling for SARS-CoV-2 testing

2021 ◽  
Author(s):  
Charles Hugo Marquette ◽  
Jacques Boutros ◽  
Jonathan Benzaquen ◽  
Marius Ilié ◽  
Mickelina Labaky ◽  
...  
Keyword(s):  
Mass Screening ◽  
Clinical Performance ◽  
Close Contact ◽  
Low Cost ◽  
Sampling Technique ◽  
Contact Tracing ◽  
Rt Pcr ◽  
Community Based ◽  
Attending Physician ◽  
Close Contacts

ABSTRACTBackgroundThe current diagnostic standard for coronavirus 2019 disease (COVID-19) is reverse transcriptase-polymerase chain reaction (RT-PCR) testing with naso-pharyngeal (NP) swabs. The invasiveness and need for trained personnel make the NP technique unsuited for repeated community-based mass screening. We developed a technique to collect saliva in a simple and easy way with the sponges that are usually used for tamponade of epistaxis. This study was carried out to validate the clinical performance of oral sponge (OS) sampling for SARS-CoV-2 testing.MethodsOver a period of 22 weeks, we collected prospectively 409 paired NP and OS samples from consecutive subjects presenting to a public community-based free screening center. Subjects were referred by their attending physician because of recent COVID-19 symptoms (n=147) or by the contact tracing staff of the French public health insurance since they were considered as close contacts of a laboratory-confirmed COVID-19 case (n=262).ResultsIn symptomatic subjects, RT-PCR SARS-CoV-2 testing with OS showed a 96.5% (95%CI: 89.6-94.8) concordance with NP testing, and, a 93.3% [95%CI: 89.1-97.3] sensitivity. In close contacts the NP-OS concordance (93.8% [95%CI: 90.9-96.7]) and OS sensitivity (71.9% [95%CI: 66.5-77.3]) were slightly lower.ConclusionThese results strongly suggest that OS testing is a straightforward, low-cost and high-throughput sampling method that can be used for frequent RT-PCR testing of COVID-19 patients and mass screening of populations.Summary of the “take home” messageOS sampling for SARS-CoV2 RT-PCR is an easy to perform, straightforward self-administered sampling technique, which has a sensitivity of up to 93.3% in symptomatic patients and 71% in close contact subjects.

scholarly journals LBTrace: A LoRa and Blockchain Based Contact Tracing Method for COVID-19 and Future Pandemics

2021 ◽  
Author(s):  
Jian Fang ◽  
Wenbo Zhao ◽  
Lei Wang ◽  
Zhenquan Qin ◽  
Bingxian Lu
Keyword(s):  
High Stability ◽  
Close Contact ◽  
Scaling Up ◽  
Contact Tracing ◽  
Smart Device ◽  
The Internet ◽  
Epidemiological Investigation ◽  
Stability And Accuracy ◽  
Tracing Method ◽  
Close Contacts

COVID-19 has caused hundreds of millions of infections and hundreds of deaths, and even though vaccinations are increasing, the mutation of the virus makes the pandemic even difficult to control. Existing manual, operator and Bluetooth-based technologies for epidemiological investigation and close contact tracing suffer from high cost, low accuracy, and difficulty in scaling up. Viruses such as Delta variants have a greater ability to survive and spread, making many of the existing human-human close contacts tracing less effective. Also, it is easy to overlook the fact that there is still a large segment of the world's population that does not have access to the Internet and is proficient in using smartphones, which makes the performance of smart device-based tracing much less effective. Inspired by Health Code and Tracetogether, which have been widely accepted in China and Singapore, we propose a LoRa and blockchain-based contact tracing method LBTrace, which is low-power, lightweight, and operation-free. The experimental results demonstrate the high stability and accuracy of our proposed method, which can be used as a complement to existing methods to help some governments effectively control COVID-19 and future outbreaks under certain emergency conditions.

scholarly journals LBTrace: A LoRa and Blockchain Based Contact Tracing Method for COVID-19 and Future Pandemics

2021 ◽  
Author(s):  
Jian Fang ◽  
Wenbo Zhao ◽  
Lei Wang ◽  
Zhenquan Qin ◽  
Bingxian Lu
Keyword(s):  
High Stability ◽  
Close Contact ◽  
Scaling Up ◽  
Contact Tracing ◽  
Smart Device ◽  
The Internet ◽  
Epidemiological Investigation ◽  
Stability And Accuracy ◽  
Tracing Method ◽  
Close Contacts

COVID-19 has caused hundreds of millions of infections and hundreds of deaths, and even though vaccinations are increasing, the mutation of the virus makes the pandemic even difficult to control. Existing manual, operator and Bluetooth-based technologies for epidemiological investigation and close contact tracing suffer from high cost, low accuracy, and difficulty in scaling up. Viruses such as Delta variants have a greater ability to survive and spread, making many of the existing human-human close contacts tracing less effective. Also, it is easy to overlook the fact that there is still a large segment of the world's population that does not have access to the Internet and is proficient in using smartphones, which makes the performance of smart device-based tracing much less effective. Inspired by Health Code and Tracetogether, which have been widely accepted in China and Singapore, we propose a LoRa and blockchain-based contact tracing method LBTrace, which is low-power, lightweight, and operation-free. The experimental results demonstrate the high stability and accuracy of our proposed method, which can be used as a complement to existing methods to help some governments effectively control COVID-19 and future outbreaks under certain emergency conditions.

scholarly journals Highlighted Prospects of an IgM/IgG Antibodies Test in Identifying Individuals With Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection

2020 ◽  
Vol 145 (1) ◽  
pp. 39-45
Author(s):  
Yaqing Li ◽  
Qiang He ◽  
Rizhen Yu ◽  
Hui Jiang ◽  
Weizhong Wang ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Severe Acute Respiratory Syndrome ◽  
Ct Scanning ◽  
Immunoglobulin M ◽  
Antibody Detection ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Imaging Results ◽  
Close Contacts ◽  
Nucleic Acid Tests

Context.— Covert severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections could be seeding new outbreaks. How to identify asymptomatic SARS-CoV-2 infections early has become a global focus. Objective.— To explore the roles of immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies detection, nucleic acid tests, and computed tomography (CT) scanning to identify asymptomatic SARS-CoV-2 infection. Design.— The clinical data of 389 individuals with close contacts, including in general characteristics, SARS-CoV-2 etiology, serum-specific IgM and IgG antibody detection and CT imaging results, were systematically analyzed. Results.— The present study showed that only 89 of 389 individuals with close contacts were positive after the first nucleic acid test, while 300 individuals were still negative after 2 nucleic acid tests. Among the 300 individuals, 75 did not have pneumonia, and the other 225 individuals had pulmonary imaging changes. A total of 143 individuals were eventually diagnosed as having asymptomatic infection through IgM antibody and IgG antibody detection. The sensitivity, specificity, and false-negative rate of IgM and IgG antibody detection were approximately 97.1% (347 of 357), 95.3% (204 of 214), and 4.67% (10 of 214), respectively. It also indicated that during approximately 2 weeks, most individuals were both IgM positive and IgG positive, accounting for 68.57% (72 of 105). During approximately 3 weeks, the proportion of IgM-positive and IgG-positive individuals decreased to 8.57% (9 of 105), and the proportion of IgM-negative and IgG-positive individuals increased to 76.19% (80 of 105). Conclusions.— There are highlighted prospects of IgM/IgG antibody detection as a preferred method in identifying the individuals with asymptomatic SARS-CoV-2 infection, especially combined with nucleic acid tests and pulmonary CT scanning.

Clinical Characteristics of Children with COVID-19: A Multicenter Study in the United Arab Emirates (Preprint)

2021 ◽  
Author(s):  
Farah Ennab ◽  
Mariam ElSaban ◽  
Eman Khalaf ◽  
Hanieh Tabatabaei ◽  
Amar Hassan Khamis ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Multicenter Study ◽  
Clinical Characteristics ◽  
Pediatric Population ◽  
Contact Tracing ◽  
Severe Illness ◽  
Published Data ◽  
Presenting Symptoms ◽  
Asymptomatic Children ◽  
Significant Difference

BACKGROUND Coronavirus disease 2019 (COVID-19) has infected over 123 million people globally. The first confirmed case in the United Arab Emirates (UAE) was reported on 29th January 2020.  COVID-19 has fared mildly in the pediatric population according to available literature out of early epicenters of the pandemic. To date there is a lack of published data about COVID-19 infection among children in the Arabian region. OBJECTIVE Investigate the clinical characteristics, laboratory findings, treatment, and outcomes of children with COVID-19. METHODS This cross-sectional multicenter study included children with confirmed COVID-19 infection admitted between March 1st and June 15th, 2020 to three large hospitals in Dubai, UAE. Serial COVID-19 polymerase chain reaction (PCR) testing was collected, and patients' demographics, pre-morbid clinical characteristics and inpatient hospital course were investigated. RESULTS 111 children were included in our study and represented 22 nationalities. Fifty-nine (53.2%) were boys. The mean age was 7 years (±5.3). 15.3% of children were younger than 1 year. Only 4 (3.6%) of the patients had pre-existing asthma all of whom had uneventful courses. At presentation 43 (38.7%) were asymptomatic, 68 (61.2%) had mild or moderate symptoms and none had severe illness requiring intensive care. Fever (20.7%), cough (19.8%) and rhinorrhea (15.3%) were the most common presenting symptoms and most symptoms resolved by day 5 of hospitalization. Most patients had no abnormality on chest x-ray. The most common laboratory abnormalities on admission included variations in neutrophil count (24.7%), aspartate transaminase (22.5%), alkaline phosphatase (36.7%) and lactate dehydrogenase (42.5%). Children were infrequently prescribed targeted medications, with only 4 (3.6%) receiving antibiotics. None of the 52 patients tested for viral co-infections were positive. COVID-19 PCR turned negative at a median of 10 days [6-14] after first positive test. Overall, there was no significant difference of time to negative PCR results between symptomatic and asymptomatic children. CONCLUSIONS This study of COVID19 presentations and characteristics presents a first look into the burden of COVID19 infection in the pediatric population in the UAE. We conclude that a large percentage of children experienced no symptoms, and severe disease is uncommon in the UAE. Various laboratory abnormalities were observed despite clinical stability. Ongoing surveillance, contact tracing and public health measures will be important to contain future outbreaks.

scholarly journals Clinical Outcomes in 55 Patients With Severe Acute Respiratory Syndrome Coronavirus 2 Who Were Asymptomatic at Hospital Admission in Shenzhen, China

2020 ◽  
Vol 221 (11) ◽  
pp. 1770-1774 ◽  
Author(s):  
Yanrong Wang ◽  
Yingxia Liu ◽  
Lei Liu ◽  
Xianfeng Wang ◽  
Nijuan Luo ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Young People ◽  
Severe Acute Respiratory Syndrome ◽  
Hospital Admission ◽  
Clinical Outcomes ◽  
Close Contact ◽  
Nucleic Acid Testing ◽  
Pharyngeal Swab ◽  
Asymptomatic Carriers ◽  
Novel Coronavirus

Abstract An epidemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has spread unexpectedly in Wuhan, Hubei Province, China, since December 2019. There are few reports about asymptomatic contacts of infected patients identified as positive for SARS-CoV-2 through screening. We studied the epidemiological and clinical outcomes in 55 asymptomatic carriers who were laboratory confirmed to be positive for SARS-CoV-2 through nucleic acid testing of pharyngeal swab samples. The asymptomatic carriers seldom occurred among young people (aged 18–29 years) who had close contact with infected family members. In the majority of patients, the outcome was mild or ordinary 2019 novel coronavirus disease during hospitalization.

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