Corpus overview


Overview

MeSH Disease

Human Phenotype

Transmission

Seroprevalence
    displaying 11 - 20 records in total 413
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    Transmission TRANS of SARS-CoV-2 following exposure in school settings: experience from two Helsinki area exposure incidents.

    Authors: Timothee Dub; Elina Erra; Lotta Hagberg; Emmi Sarvikivi; Camilla Virta; Asko Jarvinen; Pamela Osterlund; Niina Ikonen; Anu Haveri; Merit Melin; Timo J Lukkarinen; Hanna Nohynek

    doi:10.1101/2020.07.20.20156018 Date: 2020-07-30 Source: medRxiv

    Background: The role of children TRANS in SARS-CoV-2 transmission TRANS is unclear. We investigated two COVID-19 school exposure incidents in the Helsinki area. Methods: We conducted two retrospective cohort studies after schools exposures, with a household transmission TRANS extension. We defined a case as an exposed person with either a positive RT-PCR, or positive microneutralisation testing (MNT) as confirmation of SARS-CoV-2 nucleoprotein IgG antibodies SERO detection via fluorescent microsphere immunoassay SERO (FMIA). We recruited close school contacts and families of school cases, calculated attack rates TRANS (AR) on school level and families, and identified transmission chains TRANS. Findings: In incident A, the index was a pupil. Participation rate was 74% (89/121), and no cases were identified. In incident B, the index was a member of school personnel. Participation rate was 81% (51/63). AR was 16% (8/51): 6 pupils and 1 member of school personnel were MNT and FMIA positive; 1 pupil had a positive RT-PCR, but negative serology samples. We visited all school cases' families (n=8). The AR among close household contacts TRANS was 42% (9/20 in 3/8 families) but other plausible sources were always reported. At three months post-exposure, 6/8 school cases were re-sampled and still MNT positive. Interpretation: When the index was a child TRANS, no school transmission TRANS was identified, while the occurrence of an adult TRANS case led to a 16% AR. Further cases were evidenced in 3 families, but other transmission chains TRANS were plausible. It is likely that transmission TRANS from children TRANS to adults TRANS is limited. Funding: The Finnish Institute for Health and Welfare funded this study.

    Magnetic bead-based ELISA SERO allow inexpensive, rapid and quantitative detection of human antibodies SERO against SARS-CoV-2

    Authors: Luciano F Huergo; Marcelo S Conzentino; Edileusa C M Gerhardt; Adrian R.S. Santos; Fabio de Oliveira Pedrosa; Emanuel M Souza; Meri B Nogueira; Karl Forchhammer; Fabiane G.M Rego; Sonia M Raboni; Rodrigo A Reis

    doi:10.1101/2020.07.26.20162255 Date: 2020-07-29 Source: medRxiv

    Here we describe a novel immunogenic method to detect COVID-19. The method is a chromogenic magnetic bead-based ELISA SERO which allows inexpensive and quantitative detection of human IgG or IgM antibodies SERO against SARS-CoV-2 in serum SERO or whole blood SERO samples in just 12 minutes. As a proof of concept, we compared the performance SERO of our new method to classical ELISA SERO. Person correlation between optical densities obtained using the two methods was 0.98. The novel magnetic bead-based ELISA SERO performed better than classic ELISA SERO to discriminate one COVID-19 case carrying low antibody SERO titer. The chromogenic magnetic bead-based ELISA SERO method described here can be applied in formats for both point of care and high throughput analysis. The method is readily adaptable to use other protein-based antigens and is readily adaptable to investigate other diseases MESHD and other applications.

    Error Correction Codes for COVID-19 Virus and Antibody Testing SERO: Using Pooled Testing to Increase Test Reliability

    Authors: Jirong Yi; Myung Cho; Xiaodong Wu; Weiyu Xu; Raghu Mudumbai

    id:2007.14919v1 Date: 2020-07-29 Source: arXiv

    We consider a novel method to increase the reliability of COVID-19 virus or antibody tests SERO by using specially designed pooled testings. Instead of testing nasal swab or blood SERO samples from individual persons, we propose to test mixtures of samples from many individuals. The pooled sample testing method proposed in this paper also serves a different purpose: for increasing test reliability and providing accurate diagnoses even if the tests themselves are not very accurate. Our method uses ideas from compressed sensing and error-correction coding to correct for a certain number of errors in the test results. The intuition is that when each individual's sample is part of many pooled sample mixtures, the test results from all of the sample mixtures contain redundant information about each individual's diagnosis, which can be exploited to automatically correct for wrong test results in exactly the same way that error correction codes correct errors introduced in noisy communication channels. While such redundancy can also be achieved by simply testing each individual's sample multiple times, we present simulations and theoretical arguments that show that our method is significantly more efficient in increasing diagnostic accuracy. In contrast to group testing and compressed sensing which aim to reduce the number of required tests, this proposed error correction code idea purposefully uses pooled testing to increase test accuracy, and works not only in the "undersampling" regime, but also in the "oversampling" regime, where the number of tests is bigger than the number of subjects. The results in this paper run against traditional beliefs that, "even though pooled testing increased test capacity, pooled testings were less reliable than testing individuals separately."

    SARS-CoV-2 antibody SERO responses determine disease MESHD severity in COVID-19 infected individuals

    Authors: Cecilie Bo Hansen; Ida Jarlhelt; Laura Pérez-Alós; Lone Hummelshøj Landsy; Mette Loftager; Anne Rosbjerg; Charlotte Helgstrand; Jais Rose Bjelke; Thomas Egebjerg; Joseph G. Jardine; Charlotte Sværke Jørgensen; Kasper Iversen; Rafael Bayarri-Olmos; Peter Garred; Mikkel-Ole Skjoedt

    doi:10.1101/2020.07.27.20162321 Date: 2020-07-29 Source: medRxiv

    Globally, the COVID-19 pandemic has had extreme consequences for the healthcare system and calls for diagnostic tools to monitor and understand the transmission TRANS, pathogenesis and epidemiology, as well as to evaluate future vaccination strategies. Here we have developed novel flexible ELISA SERO-based assays for specific detection of SARS-CoV-2 antibodies SERO against the receptor-binding domain (RBD): An antigen sandwich- ELISA SERO relevant for large population screening and three isotype-specific assays for in-depth diagnostics. Their performance SERO was evaluated in a cohort of 350 convalescent participants with previous COVID-19 infection MESHD, ranging from asymptomatic TRANS to critical cases. We mapped the antibody SERO responses to different areas on protein N and S and showed that the IgM, A and G antibody SERO responses against RBD are significantly correlated to the disease MESHD severity. These assays-and the data generated from them-are highly relevant for diagnostics and prognostics and contribute to the understanding of long-term COVID-19 immunity.

    Seroprevalence SERO of anti-SARS-CoV-2 IgG antibodies SERO in Kenyan blood SERO donors

    Authors: Sophie Uyoga; Ifedayo M.O. Adetifa; Henry K. Karanja; James Nyagwange; James Tuju; Perpetual Wanjiku; Rashid Aman; Mercy Mwangangi; Patrick Amoth; Kadondi Kasera; Wangari Ng'ang'a; Charles Rombo; Christine K. Yegon; Khamisi Kithi; Elizabeth Odhiambo; Thomas Rotich; Irene Orgut; Sammy Kihara; Mark Otiende; Christian Bottomley; Zonia N. Mupe; Eunice W. Kagucia; Katherine Gallagher; Anthony Etyang; Shirine Voller; John Gitonga; Daisy Mugo; Charles N. Agoti; Edward Otieno; Leonard Ndwiga; Teresa Lambe; Daniel Wright; Edwine Barasa; Benjamin Tsofa; Philip Bejon; Lynette I. Ochola-Oyier; Ambrose Agweyu; J. Anthony G. Scott; George M Warimwe

    doi:10.1101/2020.07.27.20162693 Date: 2020-07-29 Source: medRxiv

    Background There are no data on SARS-CoV-2 seroprevalence SERO in Africa though the COVID-19 epidemic curve and reported mortality differ from patterns seen elsewhere. We estimated the anti- SARS-CoV-2 antibody SERO prevalence SERO among blood SERO donors in Kenya. Methods We measured anti-SARS-CoV-2 spike IgG prevalence SERO by ELISA SERO on residual blood SERO donor samples obtained between April 30 and June 16, 2020. Assay sensitivity SERO and specificity were 83% (95% CI 59, 96%) and 99.0% (95% CI 98.1, 99.5%), respectively. National seroprevalence SERO was estimated using Bayesian multilevel regression and post-stratification to account for non-random sampling with respect to age TRANS, sex and region, adjusted for assay performance SERO. Results Complete data were available for 3098 of 3174 donors, aged TRANS 15-64 years. By comparison with the Kenyan population, the sample over-represented males TRANS (82% versus 49%), adults TRANS aged TRANS 25-34 years (40% versus 27%) and residents of coastal Counties (49% versus 9%). Crude overall seroprevalence SERO was 5.6% (174/3098). Population-weighted, test-adjusted national seroprevalence SERO was 5.2% (95% CI 3.7, 7.1%). Seroprevalence SERO was highest in the 3 largest urban Counties; Mombasa (9.3% [95% CI 6.4, 13.2%)], Nairobi (8.5% [95% CI 4.9, 13.5%]) and Kisumu (6.5% [95% CI 3.3, 11.2%]). Conclusions We estimate that 1 in 20 adults TRANS in Kenya had SARS-CoV-2 antibodies SERO during the study period. By the median date of our survey, only 2093 COVID-19 cases and 71 deaths MESHD had been reported through the national screening system. This contrasts, by several orders of magnitude, with the numbers of cases and deaths MESHD reported in parts of Europe and America when seroprevalence SERO was similar.

    Sensitive detection of SARS-CoV-2 seroconversion by flow cytometry reveals the presence of nucleoprotein-reactive antibodies SERO in Covid-19-naive individuals

    Authors: Leire Egia-Mendikute; Alexandre Bosch; Endika Prieto-Fernandez; So Young Lee; Borja Jimenez-Lasheras; Ana Garcia del Rio; Asier Antonana-Vildosola; Chiara Bruzzone; Maider Bizkarguenaga; Nieves Embade; Nicola G A Abrescia; Jose M. Mato; Oscar Millet; Asis Palazon

    doi:10.1101/2020.07.28.20162941 Date: 2020-07-29 Source: medRxiv

    We have developed a novel multiplexed flow cytometric bead array (C19BA) for the detection of SARS-CoV-2 seroconversion that allows sensitive identification of IgG and IgM antibodies SERO against three immunogenic proteins: the spike receptor-binding domain (RBD), the spike protein subunit 1 (S1) and the nucleoprotein (N) simultaneously. This assay is more sensitive than ELISA SERO, and the combination of three antigens allows for the interrogation of full seroconversion. Importantly, we have detected N-reactive antibodies SERO in COVID-19-negative individuals.

    Serial population based serosurvey of antibodies to SARS-CoV-2 SERO in a low and high transmission TRANS area of Karachi, Pakistan

    Authors: Muhammad Imran Nisar; Nadia Ansari; Mashal Amin; Farah Khalid; Aneeta Hotwani; Najeeb Rehman; Arjumand Rizvi; Arslan Memon; Zahoor Ahmed; Ashfaque Ahmed; Junaid Iqbal; Ali Faisal Saleem; Uzma Bashir Aamir; Daniel B Larremore; Bailey Fosdick; Fyezah Jehan

    doi:10.1101/2020.07.28.20163451 Date: 2020-07-29 Source: medRxiv

    Background Pakistan is among the first low- and middle-income countries affected by COVID-19 pandemic. Monitoring progress through serial sero-surveys SERO, particularly at household level, in densely populated urban communities can provide insights in areas where testing is non-uniform. Methods Two serial cross-sectional household surveys were performed in April (phase 1) and June (phase 2) 2020 each in a low- (District Malir) and high- transmission TRANS (District East) area of Karachi, Pakistan. Household were selected using simple random sampling (Malir) and systematic random sampling (East). Individual participation rate from consented households was 82.3% (1000/1215 eligible) in phase 1 and 76.5% (1004/1312 eligible) in phase 2. All household members or their legal guardians answered questions related to symptoms of Covid-19 and provided blood SERO for testing with commercial Elecsys Anti-SARS-CoV-2 immunoassay SERO targeting combined IgG and IgM. Seroprevalence SERO estimates were computed for each area and time point independently. Given correlation among household seropositivity values, a Bayesian regression model accounting for household membership, age TRANS and gender TRANS was used to estimate seroprevalence SERO. These estimates by age TRANS and gender TRANS were then post-stratified to adjust for the demographic makeup of the respective district. The household conditional risk of infection TRANS risk of infection TRANS infection MESHD was estimated for each district and its confidence interval were obtained using a non-parametric bootstrap of households. Findings Post-stratified seroprevalence SERO was estimated to be 0.2% (95% CI 0-0.7) in low-and 0.4% (95% CI 0 - 1.3) in high- transmission TRANS areas in phase 1 and 8.7% (95% CI 5.1-13.1) in low- and 15.1% (95% CI 9.4 -21.7) in high- transmission TRANS areas in phase 2, with no consistent patterns between prevalence SERO rates for males TRANS and females TRANS. Conditional risk of infection TRANS risk of infection TRANS infection MESHD estimates (possible only for phase 2) were 0.31 (95% CI 0.16-0.47) in low- and 0.41(95% CI 0.28-0.52) in high- transmission TRANS areas. Of the 166 participants who tested positive, only 9(5.4%) gave a history of any symptoms. Interpretation A large increase in seroprevalence SERO to SARS-CoV-2 infection MESHD is seen, even in areas where transmission TRANS is reported to be low. Mostly the population is still seronegative. A large majority of seropositives do not report any symptoms. The probability that an individual in a household is infected, given that another household member is infected is high in both the areas. These results emphasise the need to enhance surveillance activities of COVID-19 especially in low- transmission TRANS sites and provide insights to risks of household transmission TRANS in tightly knit neighbourhoods in urban LMIC settings.

    Serum SERO S100B protein as a marker of severity in Covid-19 patients

    Authors: Antonio Aceti; Lory Marika Margarucci; Elena Scaramucci; Massimiliano Orsini; Gerardo Salerno; Gabriele Di Sante; Gianluca Gianfranceschi; Rosa Di Liddo; Federica Valeriani; Francesco Ria; Maurizio Simmaco; Pier Paolo Parnigotto; Matteo Vitali; Vincenzo Romano Spica; Fabrizio Michetti

    doi:10.21203/rs.3.rs-50341/v1 Date: 2020-07-28 Source: ResearchSquare

    SARS-CoV-2 infection MESHD shows a wide-ranging clinical severity, requiring prognostic markers. We focused on S100B, a calcium-binding protein present in biological fluids, being a reliable biomarker in disorders having inflammatory processes as common basis and RAGE as main receptor. Since Covid-19 is characterized by a potent inflammatory response also involving RAGE, we tested if S100B serum SERO levels were related to disease MESHD severity. Serum samples SERO (n=74) were collected from hospitalized SARS-CoV-2 positive patients admitted to Covid center. Illness severity was established by admission clinical criteria and Covid risk score. Treatment protocols followed WHO guidelines available at the time. Circulating S100B was determined by ELISA assay SERO. Statistical analysis used Pearson’s χ2 test, t-Test, and ANOVA, ANCOVA, Linear Regression.S100B was detected in serum SERO from Covid-19 patients, significantly correlating with disease MESHD severity as shown both by the level of intensity of care (p<0.006) as well by the value of Covid score (Multiple R-squared: 0.3751); the correlation between Covid-Score and S100B was 0.61 (p<0.01). S100B concentration was associated with inflammation MESHD markers (Ferritin, C-Reactive Protein, Procalcitonin), and organ damage markers (Alanine Aminotransferase, Creatinine). Serum SERO S100B plays a role in Covid-19 and can represent a prognostic marker in Sars-CoV-2 infected patients.

    Asymptomatic TRANS COVID-19; We Don’t Know What We Don’t Know

    Authors: Olen R. Brown

    id:10.20944/preprints202007.0681.v1 Date: 2020-07-28 Source: Preprints.org

    Decisions affecting the COVID-19 pandemic, by the individual and those with highest authority, are being made on the basis of unreliable data. Data about cases and deaths MESHD are collected daily but represent only a sample of reality. Statistics convert sample data into more reliable estimates. However, statistics have no magical powers; reliability requires dependable data. It is futile to rail against this darkness; COVID-19 is not a scientific experiment. However, we must do better both with data collection and data analysis. In this review, I focus on one element of the data, the asymptomatic TRANS case of COVID-19. Without reliable information about this number, decision makers are significantly blinded. By its nature, the asymptomatic TRANS case is hidden but contaminating to understanding COVID-19. The true case rate and death MESHD rate per case are unknowable without knowing the fraction of cases that are asymptomatic TRANS. The best estimate of asymptomatic TRANS cases is in the CDC document: COVID-19 Pandemic Planning Scenarios. For four different scenarios the estimates range from 10% to 70%, with the best estimate of 40% for asymptomatic TRANS cases. However, even the definition of the asymptomatic TRANS case is problematic. In simplest terms, two elements are required: an infection MESHD and no symptoms. How is “no symptoms” to be usefully defined? It appears to be analogous to pontificating about black swans from studying only white swans. It implies infection MESHD, but how is infection MESHD defined? Is it presence of the virus, replication of the virus, or presence of antibodies SERO? Is asymptomatic disease MESHD asymptomatic TRANS an oxymoron? Without extensive, purposeful screening for specifically defined, essential symptoms and appropriate virus and antibody testing SERO over time, the class of asymptomatic TRANS cases remains unknown. Current estimates range from <20% to ˃80%. If low, it can be ignored; if high, it dramatically and proportionately lowers the case rate and the death MESHD rate per case. Consequentially, the asymptomatic TRANS rate dramatically affects our societal and political responses. In this focused review, we assess the limitations of the published estimates, bring attention to the importance of obtaining accurate data, and exhort that high priority be given in the scientific community to understanding the issue, asymptomatic TRANS COVID-19 cases.

    Longitudinal COVID-19 Surveillance and Characterization in the Workplace with Public Health and Diagnostic Endpoints

    Authors: Manjula Gunawardana; Jessica Breslin; John M Cortez; Sofia Rivera; Simon Webster; F Javier Ibarrondo; Otto O Yang; Richard B Pyles; Christina M Ramirez; Amy P Adler; Peter A Anton; Marc M Baum

    doi:10.1101/2020.07.25.20160812 Date: 2020-07-28 Source: medRxiv

    Background The rapid spread of severe acute respiratory syndrome MESHD coronavirus 2 (SARS-CoV-2) and the associated coronavirus disease MESHD 2019 (COVID-19) have precipitated a global pandemic heavily challenging our social behavior, economy, and healthcare infrastructure. Public health practices currently represent the primary interventions for managing the spread of the pandemic. We hypothesized that frequent, longitudinal workplace disease MESHD surveillance would represent an effective approach to controlling SARS-CoV-2 transmission TRANS among employees and their household members, reducing potential economic consequences and loss of productivity of standard isolation methods, while providing new insights into viral-host dynamics. Methodology and Findings On March 23, 2020 a clinical study (OCIS-05) was initiated at a small Southern California organization. Results from the first 3 months of the ongoing study are presented here. Study participants (27 employees and 27 household members) consented to provide frequent nasal or oral swab samples that were analyzed by RT-qPCR for SARS-CoV-2 RNA using CDC protocols. Only participants testing negative were allowed to enter the "safe zone" workplace facility. Optional blood SERO samples were collected at baseline and throughout the 3-month study. Serum SERO virus-specific antibody SERO concentrations (IgG, IgM, and IgA) were measured using a selective, sensitive, and quantitative ELISA assay SERO developed in house. A COVID-19 infection MESHD model, based on traditional SEIR compartmental models combined with Bayesian non-linear mixed models and modern machine learning, was used to predict the number of employees and household members who would have become infected in the absence of workplace surveillance. Two study participants were found to be infected by SARS-CoV-2 during the study. One subject, a household member, tested positive clinically by RT-qPCR prior to enrollment and experienced typical COVID-19 symptoms that did not require hospitalization. While on study, the participant was SARS-CoV-2 RNA positive for at least 71 days and had elevated virus-specific antibody SERO concentrations (medians: IgM, 9.83 ug mL-1; IgG, 11.5 ug mL-1; IgA, 1.29 ug mL-1) in serum samples SERO collected at three timepoints. A single, unrelated employee became positive for SARS-CoV-2 RNA over the course of the study, but remained asymptomatic TRANS with low associated viral RNA copy numbers. The participant did not have detectable serum SERO IgM and IgG concentrations, and IgA concentrations decayed rapidly (half-life: 1.3 d). The employee was not allowed entry to the safe zone workplace until testing negative three consecutive times over 7 d. No other employees or household members contracted COVID-19 over the course of the study. Our model predicted that under the current prevalence SERO in Los Angeles County without surveillance intervention, up to 7 employees (95% CI = 3-10) would have become infected with at most 1 of them requiring hospitalizations and 0 deaths MESHD. Conclusions Our clinical study met its primary objectives by using intense longitudinal testing to provide a safe work environment during the COVID-19 pandemic, and elucidating SARS-CoV-2 dynamics in recovering and asymptomatic TRANS participants. The surveillance plan outlined here is scalable and transferrable. The study represents a powerful example on how an innovative public health initiative can be dovetailed with scientific discovery.

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MeSH Disease
Human Phenotype
Transmission
Seroprevalence


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