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Asymptomatic carrier

About: Asymptomatic carrier is a(n) research topic. Over the lifetime, 1312 publication(s) have been published within this topic receiving 44147 citation(s). The topic is also known as: healthy carrier & carrier. more


Open accessJournal ArticleDOI: 10.1001/JAMA.2020.2565
Yan Bai, Lingsheng Yao, Tao Wei, Fei Tian1  +3 moreInstitutions (2)
14 Apr 2020-JAMA
Abstract: This study describes possible transmission of novel coronavirus disease 2019 (COVID-19) from an asymptomatic Wuhan resident to 5 family members in Anyang, a Chinese city in the neighboring province of Hubei. more

Topics: Asymptomatic carrier (57%)

3,104 Citations

Open accessJournal ArticleDOI: 10.1001/JAMA.2020.12839
25 Aug 2020-JAMA
Abstract: Importance The coronavirus disease 2019 (COVID-19) pandemic, due to the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a worldwide sudden and substantial increase in hospitalizations for pneumonia with multiorgan disease. This review discusses current evidence regarding the pathophysiology, transmission, diagnosis, and management of COVID-19. Observations SARS-CoV-2 is spread primarily via respiratory droplets during close face-to-face contact. Infection can be spread by asymptomatic, presymptomatic, and symptomatic carriers. The average time from exposure to symptom onset is 5 days, and 97.5% of people who develop symptoms do so within 11.5 days. The most common symptoms are fever, dry cough, and shortness of breath. Radiographic and laboratory abnormalities, such as lymphopenia and elevated lactate dehydrogenase, are common, but nonspecific. Diagnosis is made by detection of SARS-CoV-2 via reverse transcription polymerase chain reaction testing, although false-negative test results may occur in up to 20% to 67% of patients; however, this is dependent on the quality and timing of testing. Manifestations of COVID-19 include asymptomatic carriers and fulminant disease characterized by sepsis and acute respiratory failure. Approximately 5% of patients with COVID-19, and 20% of those hospitalized, experience severe symptoms necessitating intensive care. More than 75% of patients hospitalized with COVID-19 require supplemental oxygen. Treatment for individuals with COVID-19 includes best practices for supportive management of acute hypoxic respiratory failure. Emerging data indicate that dexamethasone therapy reduces 28-day mortality in patients requiring supplemental oxygen compared with usual care (21.6% vs 24.6%; age-adjusted rate ratio, 0.83 [95% CI, 0.74-0.92]) and that remdesivir improves time to recovery (hospital discharge or no supplemental oxygen requirement) from 15 to 11 days. In a randomized trial of 103 patients with COVID-19, convalescent plasma did not shorten time to recovery. Ongoing trials are testing antiviral therapies, immune modulators, and anticoagulants. The case-fatality rate for COVID-19 varies markedly by age, ranging from 0.3 deaths per 1000 cases among patients aged 5 to 17 years to 304.9 deaths per 1000 cases among patients aged 85 years or older in the US. Among patients hospitalized in the intensive care unit, the case fatality is up to 40%. At least 120 SARS-CoV-2 vaccines are under development. Until an effective vaccine is available, the primary methods to reduce spread are face masks, social distancing, and contact tracing. Monoclonal antibodies and hyperimmune globulin may provide additional preventive strategies. Conclusions and Relevance As of July 1, 2020, more than 10 million people worldwide had been infected with SARS-CoV-2. Many aspects of transmission, infection, and treatment remain unclear. Advances in prevention and effective management of COVID-19 will require basic and clinical investigation and public health and clinical interventions. more

Topics: Intensive care (57%), Respiratory failure (54%), Case fatality rate (53%) more

1,665 Citations

Open accessJournal ArticleDOI: 10.1007/S11427-020-1661-4
Zhiliang Hu1, Zhiliang Hu2, Ci Song1, Chuanjun Xu2  +11 moreInstitutions (2)
Abstract: Previous 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. Epidemiological 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. As a result, none of the 24 asymptomatic cases presented any obvious symptoms while 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. Overall, the 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. more

Topics: Asymptomatic (61%), Asymptomatic carrier (61%)

969 Citations

Journal ArticleDOI: 10.1056/NEJM200002103420604
Abstract: Background Clostridium difficile infection can result in asymptomatic carriage, mild diarrhea, or fulminant pseudomembranous colitis. We studied whether antibody responses to C. difficile toxins affect the risks of colonization, diarrhea, and asymptomatic carriage. Methods We prospectively studied C. difficile infections in hospitalized patients who were receiv-ing antibiotics. Serial stool samples were tested for C. difficile colonization by cytotoxin assay and culture. Serum antibody (IgA, IgG, and IgM) levels and fecal antibody (IgA and IgG) levels against C. difficile toxin A, toxin B, and nontoxin antigens were measured by an enzyme-linked immunosorbent assay (ELISA). Results Of 271 patients, 37 (14 percent) were colonized with C. difficile at the time of admission, 18 of whom were asymptomatic carriers. An additional 47 patients (17 percent) became infected in the hospital, 19 of whom remained asymptomatic. The base-line antibody levels were similar in the patients who later became colonized and tho... more

Topics: Bezlotoxumab (71%), Pseudomembranous colitis (67%), Clostridium difficile (65%) more

933 Citations

Journal ArticleDOI: 10.1016/S0016-5085(00)70261-7
01 Mar 2000-Gastroenterology
Abstract: Background & Aims: Six genotypes (A‐F) of hepatitis B virus (HBV) have been identified; however, the genotype-related differences in the pathogenicity of HBV remain unknown. Therefore, we investigated the prevalence of HBV genotypes in Taiwan and the association between distinct genotypes and severity of liver disease in a cross-sectional study. Methods: Using a molecular method, HBV genotypes were determined in 100 asymptomatic carriers and in 170 patients with histologically verified chronic liver disease and hepatocellular carcinoma (HCC). Results: All genotypes except genotype E were identified in Taiwan, and genotypes B and C were predominant. Genotype C was prevalent in patients with cirrhosis and in those with HCC who were older than 50 years compared with age-matched asymptomatic carriers (60% vs. 23%, P , 0.001, and 41% vs. 15%, P 5 0.005, respectively). Genotype B was significantly more common in patients with HCC aged less than 50 years compared with age-matched asymptomatic carriers (80% vs. 52%, P 5 0.03). This predominance was more marked in younger patients with HCC (90% in those aged #35 years), most of whom did not have cirrhosis. Conclusions: Our data suggest that HBV genotype C is associated with more severe liver disease and genotype B may be associated with the development of HCC in young Taiwanese. However, additional large-scale longitudinal studies are needed to confirm the relationship of HBV genotypes to liver disease severity and clinical outcomes. more

Topics: Hepatitis B virus (60%), Hepatitis B (58%), Liver disease (56%) more

914 Citations

No. of papers in the topic in previous years

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Topic's top 5 most impactful authors

Curtis J. Donskey

5 papers, 690 citations

Mario Rizzetto

4 papers, 217 citations

Didier Raoult

4 papers, 273 citations

Paolo Prandoni

4 papers, 265 citations

Guangwen Cao

4 papers, 175 citations

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