Corpus overview


MeSH Disease

Human Phenotype

Cough (5)

Fever (5)

Pneumonia (3)

Falls (2)

Anosmia (2)


    displaying 31 - 40 records in total 44
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    Clinical evaluation of self-collected saliva by RT-qPCR, direct RT-qPCR, RT-LAMP, and a rapid antigen test to diagnose COVID-19

    Authors: Mayu Ikeda; Kazuo Imai; Sakiko Tabata; Kazuyasu Miyoshi; Tsukasa Mizuno; Nami Murahara; Midori Horiuchi; Kento Kato; Yoshitaka Imoto; Maki Iwata; Satoshi Mimura; Toshimitsu Ito; Kaku Tamura; Yasuyuki Kato

    doi:10.1101/2020.06.06.20124123 Date: 2020-06-08 Source: medRxiv

    Background The clinical performance SERO of six molecular diagnostic tests and a rapid SERO antigen test for severe acute respiratory syndrome coronavirus 2 MESHD (SARS-CoV-2) were clinically evaluated for the diagnosis of coronavirus disease MESHD 2019 (COVID-19) in self-collected saliva. Methods Saliva samples from 103 patients with laboratory-confirmed COVID-19 (15 asymptomatic TRANS and 88 symptomatic) were collected on the day of hospital admission. SARS-CoV-2 RNA in saliva was detected using a quantitative reverse-transcription polymerase chain reaction (RT-qPCR) laboratory-developed test (LDT), a cobas SARS-CoV-2 high-throughput system, three direct RT-qPCR kits, and reverse-transcription loop mediated isothermal amplification (RT-LAMP). Viral antigen was detected by a rapid antigen immunochromatographic assay. Results Of the 103 samples, viral RNA was detected in 50.5-81.6% of the specimens by molecular diagnostic tests and an antigen was detected in 11.7% of the specimens by the rapid antigen test. Viral RNA was detected at a significantly higher percentage (65.6-93.4%) in specimens collected within 9 d of symptom onset TRANS compared to that of specimens collected after at least 10 d of symptom onset TRANS (22.2-66.7%) and that of asymptomatic TRANS patients (40.0-66.7%). Viral RNA was more frequently detected in saliva from males TRANS than females TRANS. Conclusions Self-collected saliva is an alternative specimen diagnosing COVID-19. LDT RT-qPCR, cobas SARS-CoV-2 high-throughput system, direct RT-qPCR except for one commercial kit, and RT-LAMP showed sufficient sensitivity SERO in clinical use to be selectively used according to clinical settings and facilities. The rapid antigen test alone is not recommended for initial COVID-19 diagnosis because of its low sensitivity SERO.

    Serology confirms SARS-CoV-2 infection MESHD in PCR-negative children TRANS presenting with Paediatric Inflammatory Multi-System Syndrome MESHD

    Authors: Marisol Perez-Toledo; Sian E. Faustini; Sian E. Jossi; Adrian Shields; Hari Krishnan Kanthimathinathan; Joel D. Allen; Yasunori Watanabe; Margaret Goodall; David C. Wraith; Tonny V. Veenith; Mark T. Drayson; Deepthi Jyothish; Eslam Al-Abadi; Ashish Chikermane; Steven Welch; Kavitha Masilamani; Scott Hackett; Max Crispin; Barnaby Scholefield; Adam F. Cunningham; Alex G. Richter

    doi:10.1101/2020.06.05.20123117 Date: 2020-06-07 Source: medRxiv

    Background. During the COVID-19 outbreak, reports have surfaced of children TRANS who present with features of a multisystem inflammatory syndrome MESHD with overlapping features of Kawasaki disease MESHD and toxic shock syndrome - Paediatric Inflammatory Multisystem Syndrome MESHD shock HP syndrome - Paediatric Inflammatory Multisystem Syndrome- temporally associated with SARS-CoV-2 pandemic (PIMS-TS). Initial reports find that many of the children TRANS are PCR-negative for SARS-CoV-2, so it is difficult to confirm whether this syndrome is a late complication of viral infection MESHD in an age group TRANS largely spared the worst consequences of this infection, or if this syndrome reflects enhanced surveillance. Methods. Children TRANS hospitalised for symptoms consistent with PIMS-TS between 28 April and 8 May 2020, and who were PCR-negative for SARS-CoV-2, were tested for antibodies SERO to viral spike glycoprotein using an ELISA SERO test. Results. Eight patients ( age TRANS range 7-14 years, 63% male TRANS) fulfilled case-definition for PIMS-TS during the study period. Six of the eight patients required admission to intensive care. All patients exhibited significant IgG and IgA responses to viral spike glycoprotein. Further assessment showed that the IgG isotypes detected in children TRANS with PIMS-TS were of the IgG1 and IgG3 subclasses, a distribution similar to that observed in samples from hospitalised adult TRANS COVID-19 patients. In contrast, IgG2 and IgG4 were not detected in children TRANS or adults TRANS. IgM was not detected in children TRANS, which contrasts with adult TRANS hospitalised adult TRANS COVID-19 patients of whom all had positive IgM responses. Conclusions. Strong IgG antibody SERO responses can be detected in PCR-negative children TRANS with PIMS-TS. The low detection rate of IgM in these patients is consistent with infection MESHD having occurred weeks previously and that the syndrome onset occurs well after the control of SARS-CoV-2 viral load. This implies that the disease is largely immune-mediated. Lastly, this indicates that serology can be an appropriate diagnostic tool in select patient groups.

    Rapid point of care nucleic acid testing for SARS-CoV-2 in hospitalised patients: a clinical trial and implementation study

    Authors: Dami A Collier; Sonny M Assennato; Nyarie Sithole; Katherine Sharrocks; Allyson Ritchie; Pooja Ravji; Matt Routledge; Dominic Sparkes; Jordan Skittrall; Ben Warne; Anna smielewska; ISOBEL RAMSEY; NEHA GOEL; MARTIN CURRAN; DAVID ENOCH; RHYS TASSELL; MICHELLE LINEHAM; DEVAN VAGHELA; CLARE LEONG; HOI PING MOK; JOHN BRADLEY; KENNETH GC SMITH; Vivien Mendoza; NIKOS DEMIRIS; MARTIN BESSER; GORDON DOUGAN; PAUL J LEHNER; Mark Siedner; HONGYI ZHANG; CLAIRE WADDINGTON; HELEN LEE; Ravindra K Gupta

    doi:10.1101/2020.05.31.20114520 Date: 2020-06-02 Source: medRxiv

    Objective To compare a point of care (POC) nucleic acid amplification based platform for rapid diagnosis of COVID-19 against the standard laboratory RT-PCR test and perform an implementation study. Design: prospective clinical trial (COVIDx) and observational study Setting: a large UK teaching hospital Participants: patients presenting to hospital with possible COVID-19 disease and tested on a combined nasal/throat swab using the SAMBA II SARS-CoV-2 rapid POC test SERO and in parallel a combined nasal/throat swab for standard lab RT-PCR testing. Implementation phase participants underwent SARS-CoV-2 POC testing SERO for a range of indications over a ten day period pre and post SAMBA II platform implementation. Main outcome measures: concordance and sensitivity SERO and specificity of POC using the lab test as the reference standard, test turnaround time in trial and implementation periods; time to definitive patient triage from ED, time spent on COVID-19 holding wards, bay closures avoided, proportions of patients in isolation rooms following test, proportions of patients able to be moved to COVID negative areas following test. Results 149 participants were included in the COVIDx trial. 32 (21.5%) tested positive and 117 (78.5%) tested negative by standard lab RT-PCR. Median age TRANS was 62.7 (IQR 37 to 79) years and 47% were male TRANS. Cohen's kappa correlation between the index and reference tests was 0.96, 95% CI (0.91, 1.00). Sensitivity SERO and specificity of SAMBA against the RT-PCR lab test were 96.9% (95% CI 0.838-0.999) and 99.1% (0.953-0.999) respectively. Median time to result was 2.6 hours (IQR 2.3 to 4.8) for SAMBA II and 26.4 hours (IQR 21.4 to 31.4) for the standard lab RT-PCR test (p<0.001). In the first 10 days of the SAMBA II SARS-CoV-2 test implementation for all hospital COVID-19 testing, analysis of the first 992 tests showed 59.8% of tests were used for ED patients, and the remainder were done for pre-operative screening (11.3%), discharges to nursing homes (10%), in-hospital screening of new symptoms (9.7%), screening in asymptomatic TRANS patients requiring hospital admission screening (3.8%) and access to interventions such as dialysis and chemotherapy for high risk patients (1.2%). Use of single occupancy rooms amongst those tested fell HP from 30.8% before to 21.2% after testing (p=0.03). 11 bay closures were avoided by use of SAMBA over ten days. The post implementation group was then compared with 599 individuals who had a standard lab RT-PCR test in the 10 days prior to SAMBA introduction. Median time to result during implementation fell HP from 39.4 hours (IQR 24.7-51.3) to 3.6 hours (IQR 2.6-5.8), p<0.0001 and the median time to definitive ward move from ED was significantly reduced from 24.1 hours (9.2-48.6) to 18.5 hours (10.2-28.8), p=0.002. Mean length of stay on a COVID-19 holding ward decreased from 58.5 hours to 29.9 hours (p<0.001) compared to the 10 days prior to implementation. Conclusions SAMBA II SARS-CoV-2 rapid POC test SERO performed as well as standard lab RT-PCR and demonstrated shorter time to result both in trial and real-world settings. It was also associated with faster time to triage from the ED, release of isolation rooms, avoidance of hospital bay closures and movement of patients to COVID negative open green category wards, allowed discharge to care homes and expediting access to hospital investigations and procedures. POC testing SERO will be instrumental in mitigating the impact of COVID-19 on hospital systems by allowing rapid triage and patient movement to safe and appropriate isolation wards in the hospital. This is also likely to reduce delays in patients accessing appropriate investigation and treatment, thereby improving clinical outcomes.


    Authors: Isabel Galan; Maria Velasco; M Luisa Casas; M Jose Goyanes; Gil Rodriguez-Caravaca; Juan E Losa; Carmen Noguera; Virgilio Castilla; - Working Group Alcorcon COVID-19 investigators

    doi:10.1101/2020.05.29.20116731 Date: 2020-05-29 Source: medRxiv

    Background: Health-care workers (HCW) are at increased risk for SARS-CoV-2 infection MESHD, but few studies have evaluated prevalence SERO of antibodies SERO against SARS-CoV-2 among them. Objective: To determine the seroprevalence SERO against SARS-CoV-2 in all HCW. Methods. Cross-sectional study (April 14th- 27th , 2020) of all HCW at Hospital Universitario Fundacion Alcorcon, a second level teaching hospital in Madrid, Spain. SARS-CoV-2 IgG was measured by ELISA SERO. HCW were classified by professional category, working area, and risk for SARS-CoV-2 exposure. Results: Among 2919 HCW, 2590 (90.5%) were evaluated. Mean age TRANS was 43.8 years (SD 11.1) and 73.9% were females TRANS. Globally, 818 (31.6%) workers were IgG positive, with no differences for age TRANS, sex or previous diseases. Among them, 48.5% did not report previous symptoms. Seropositivity was more frequent in high (33.1%) and medium (33.8%) than in low-risk areas (25.8%, p=0.007), but no difference was found for hospitalization areas attending COVID-19 and non-COVID-19 patients (35.5 vs 38.3% p=NS). HCW with a previous SARS-CoV2 PCR positive test were IgG seropositive in 90.8%. By multivariate logistic regression analysis, seropositivity was associated with being physicians (OR 2.37, CI95% 1.61-3.49), nurses (OR 1.67, CI95% 1.14-2.46), or nurse- assistants (OR 1.84, CI95% 1.24-2.73), HCW working at COVID-19 hospitalization areas (OR 1.71, CI95% 1.22-2.40), non-COVID-19 hospitalization areas (OR 1.88, CI95% 1.30-2.73), and at the Emergency Room (OR 1.51, CI95% 1.01-2.27) Conclusions: Seroprevalence SERO uncovered a high rate of infection MESHD previously unnoticed among HCW. Patients not suspected of having COVID-19 as well as asymptomatic TRANS HCW may be a relevant source for nosocomial SARS-CoV-2 transmission TRANS.

    Seroprevalence SERO of antibodies SERO against SARS-CoV-2 among public community and health-care workers in Alzintan City of Libya

    Authors: ABDULWAHAB M. KAMMON; Ali A. El-Arabi; Esadk A. Erhouma; Taha M. Mehemed; Othman A. Mohamed

    doi:10.1101/2020.05.25.20109470 Date: 2020-05-26 Source: medRxiv

    Abstract A study was conducted to determine the seroprevalence SERO of antibodies SERO against SARS-CoV-2 among public community and health care workers in Alzintan City, Libya. During the period from 2/4/2020 to 18/5/2020, a total of 219 blood SERO samples were collected and analyzed for the presence of antibodies SERO against SARS-CoV-2. Collection of samples were divided in two categories; random samples from public community and samples from health care workers belong to two Governmental hospitals and one private clinic. One Step Novel Coronavirus (COVID-19) IgM/IgG Antibody Test SERO was used. Out of the 219 samples tested, 6 (2.74%) samples were seropositive for SARS-CoV-2. All health-care workers were tested negative. All positive cases were females TRANS and 5 of them aged TRANS between 44 to 75 years and one aged TRANS 32 years. The prevalence SERO in young females TRANS ([≤]40 years) was 1.4% in total young females TRANS tested in the study and 1.75% in young females TRANS taken from public community. The prevalence SERO in older females TRANS aged TRANS ( 40 years), was 11.1% in total females TRANS tested and 13.9% in females TRANS taken from public community. In conclusion, the preliminary investigation of SARS-CoV-2 revealed considerable prevalence SERO in Alzintan City although the disease seems to be in its mild form. Active surveillance studies with high number of samples using both virological and serological tests SERO are in urgent need.

    Study on the expression levels of antibodies SERO against SARS-CoV-2 at different period of disease and its related factors in 192 cases of COVID-19 patients

    Authors: Jingyi Ou; Mingkai Tan; Haolan He; Haiyan Tan; Jiewen Mai; Yaoxiang Long; Xiaowen Jiang; Qing He; Ying Huang; Yan Li; Renshen Chen; Liya Li; Fang Li; Yaling Shi

    doi:10.1101/2020.05.22.20102525 Date: 2020-05-26 Source: medRxiv

    Background: In 2020 the current outbreak of Coronavirus Disease MESHD 2019(COVID-19) has constituted a global pandemic. But the question about the immune mechanism of patients with COVID-19 is unclear and cause particular concern to the world. Here, we launched a follow-up analysis of antibodies SERO against SARS-CoV-2 of 192 COVID-19 patients, aiming to depict a kinetics profile of antibodies SERO against SARS-CoV-2 and explore the related factors of antibodies SERO expression against SARS-CoV-2 in COVID-19 patient. Methods: A total of 192 COVID-19 patients enrolled in the designated hospital of Guangzhou , Guangzhou Eighth People MESHD's Hospital, from January to February 2020 were selected as the study cohort. A cohort of 130 COVID-19 suspects who had been excluded from SARS-CoV-2 infected MESHD by negative RT-PCR result and 209 healthy people were enrolled in this study. Detection of IgM and IgG against SARS-CoV-2 were performed by Chemiluminescence immunoassay SERO in different groups . Results: It has been found that the seroconversion time of IgM against SARS-CoV-2 in most patients was 5-10 days after the symptoms onset TRANS , and then rose rapidly, reaching a peak around 2 to 3 weeks, and the median peak concentration was 2.705 AU / mL. The peak of IgM maintained within one week, and then enters the descending channel. IgG seroconverted later than or synchronously with IgM, reaching peaks around 3 to 4 weeks.The median peak concentration was 33.998AU / ml,which was higher than that of IgM . IgM titers begins to gradually decrease after reaching the peak in the 4th week, after the 8th week, a majority of IgM in patient's serum SERO started to turn negative. On the contrary, titers of IgG began to decline slightly after the fifth week, and more than 90% of results of patients were positive after 8 weeks. Additionally, the concentration of antibodies SERO positively correlated with the severity of the disease and the duration of virus exist in host. Conclusion: We depict a kinetics profile of antibodies SERO against SARS-CoV-2 in COVID-19 patients and found out that the levels of antibodies SERO were related to the disease severity, age TRANS, gender TRANS and virus clearance or continuous proliferation of COVID-19 patients.

    Preliminary evaluation of the safety and efficacy of oral human antimicrobial peptide LL-37 in the treatment of patients of COVID-19, a small-scale, single-arm, exploratory safety study

    Authors: Hanlin Zhang; Yiming Zhao; Xiaoxiao Jiang; Yuying Zhao; Yang Li; Chen Li; Meng Dong; Zhe Luan; Chunlong Yan; Jianwei Jiao; Chaoyue Zhao; Hongyue Li; Wei Chen; Cong Feng; Le Tian; Enqiang Qin; Jinsong Mu; Congyong Li; Tianshu Zeng; Shibo Feng; Shufeng Wang; Xizhou Guan; Tanshi Li; Haotian Yu; Aihua Zheng; Wanzhu Jin; Gang Sun

    doi:10.1101/2020.05.11.20064584 Date: 2020-05-15 Source: medRxiv

    Background& Aims: The Coronavirus Disease MESHD 2019 (COVID-19) has become a global epidemic and has caused a lasting and huge loss of life security, economic development and social stability in more than 180 countries around the world. Unfortunately, there is still no specific treatment for COVID-19 till now, therefore, at this point, all potential therapies need to be critically considered. LL-37 is one of the best-studied human antimicrobial peptide (AMPs) that has a broad-spectrum activity against bacteria and viruses. The use of living, genetically modified organisms (GMOs) is an effective approach for delivery of therapeutic proteins. The aim of this study was to determine the safety and efficacy of the Lactococcus lactis which has been genetically modified to produce the therapeutic human antimicrobial peptide LL-37 (herein after referred to cas001) in the patients of COVID-19. Methods: Firstly we constructed genetically modified food-grade probiotic, Lactococcus lactis, with sequence of seven tandem repeats of mature human LL-37 under control of the nisin-inducible nisA promoter to produce the cas001. A total of 20 healthy SD rats, half male TRANS and half female TRANS (There were five male TRANS and five female TRANS in the control group, the same in treatment group) were used to observe the acute toxic reaction and death MESHD after daily administration of cas001 for three weeks, which helps to provide necessary reference basis for clinical dose selection, verificaition of toxic reaction and possible target organs. According to the estimated clinical dosage of 1 x 108CFU /kg/day, considering the conversion of body surface area, the dose for rats should be multiplied by 6.17 to 6 x 108 CFU/kg/day. We administrated 100 times higher dose at 6 x 1010 CFU/kg/day to rats. In order to investigate the pharmacokinetics of cas001, male TRANS SD rats (body weight 250-300g, 1 x 1010 /animal, n=3) were given oral administration of LL-37 bacteria powder. The concentration of LL-37 in the blood SERO before and after gavage was detected by ELISA SERO kit (Hycult biotechnology Cat# HK321). Human clinical study was approved by Ethics committee of Chinese PLA General Hospital (S2020-074-04) and a total of 11 patients with mild symptoms were enrolled in Wuhan hankou hospital and Huoshenshan hospital. They were enrolled voluntarily and all patients signed informed consent. Among them, there were 5 males TRANS and 6 females TRANS, aged TRANS 55 {+/-} 12 (36-70) years old, and the duration from onset to medication enrollment was 35 {+/-} 19 (5-68) days. 6 patients were nucleic acid positive and 5 patients were nucleic acid negative when they were enrolled. All patients received the oral drug cas001 treatment according to requirement(1 x 109 CFU/capsule, 3 capsules/time, three times a day for 3weeks), with an average follow-up time of 33 {+/-} 15 days (see table 1 for the results). Findings: Western blot analysis shows that reasonable amount of LL-37 were induced by different concentrations of nisin, which means we have successfully constructed cas001. In the pre-clinical safety evaluation test, after three weeks administration of cas001, no adverse effects were observed on the rat's body weight, food and water intake, hematological MESHD or serum SERO biochemical parameters. The results showed that the LD50 of cas001 was higher than that of the 100 times of the expected clinical dose of 6 x 1010 CFU/day. These results showed that cas001 could be safe in animal experiments. In addition, rat pharmacokinetics results showed that the serum SERO concentration of LL-37 reached peak 2 hours after gavage of cas001 and returned to basal level 6 hours after gavage. During study period, the volunteers did not feel any discomfort while taking the cas001 capsules, and two hours after oral administration, the concentration of LL-37 were increased in healthy volunteers. cas001 shows definite effect in the improvement of gastrointestinal symptoms MESHD and is possible to have effects in improving the systemic symptoms and respiratory symptoms and may play a role in the improvement of results of nucleic acid test and lung CT test. 11 patients enrolled showed good compliance, tolerance, subjective feeling and actively interacted with the doctors. None of the patients had any adverse reactions. Conclusions Based on above observations, we conclude here that as an oral anti-viral agent, cas001 displayed good safety profiles. It is very hard to reach conclusion of clinical outcomes related to the cas001, although changes of several symptoms indicate encouraging findings.

    Epidemiological Characteristics of COVID-19 Patients in Vietnam and a Description of Disease Control and Prevention Measures in Thai Binh Province

    Authors: Van Thuan Hoang; Thi Dung Pham; Thi Loi Dao; Duc Thanh Nguyen; Van Nghiem Dang; Thanh Tung Dao; Van Luong Nguyen; Quang Huy Dang; Xuan Cap Do; Van Thom Nguyen; Van Diu Pham; Phong Tuc Vu; Nang Trong Hoang; Philippe Gautret; Duy Cuong Nguyen

    id:10.20944/preprints202005.0197.v1 Date: 2020-05-11 Source:

    IntroductionThe aim of this study is to describe the epidemiology of all COVID-19 patients in Vietnam and to describe the measures of disease control and prevention implemented. MethodsData were recovered from Wikipedia regarding the 2020 coronavirus pandemic in Vietnam. The period covered was from 23 January to 20 April 2020. Descriptive analysis was stratified by gender TRANS, age TRANS, country of origin, travel TRANS history, clinical symptoms and outcome. A survey of disease control and prevention measures was conducted at the Centre for Disease Control in the Thai Binh province, which is responsible for screening and isolating individuals at high risk of COVID-19. ResultsAs of 20 April 2020, Vietnam had recorded 268 confirmed COVID-19 patients. 55.2% were female TRANS. 67.9% were aged TRANS 20-49 years and 82.5% were Vietnamese. 60.4% of cases were imported from outside Vietnam. Other cases were acquired in Vietnam by individuals in close contact TRANS with imported cases. Only one patient who had not travelled TRANS had had no known contact with a confirmed case TRANS. 63.1% of patients were asymptomatic TRANS. 75.7% of patients were discharged. No deaths were recorded. The Thai Binh CDC surveyed a total of 2,203 persons at risk of COVID-19. 336 persons (15.2%) were isolated at hospitals and 1,411 (64.0%) in dedicated isolation facilities. 16.4% reported at least one respiratory symptom. No positive cases confirmed TRANS by RT-PCR have been reported in the Thai Binh province to date. ConclusionThe effect of the systematic screening and isolation strategy made it possible to limit local transmission TRANS in Vietnam. Vietnam needs to reinforce diagnostic capacities, prevention measures and provide the necessary epidemiological data on which to base interventions. The wider use of rapid serological tests SERO is also advisable in order to be able to conduct extensive screening in the community.

    Validation of a commercially available SARS-CoV-2 serological Immunoassay SERO

    Authors: Benjamin Meyer; Giulia Torriani; Sabine Yerly; Lena Mazza; Adrien Calame; Isabelle Arm-Vernez; Gert Zimmer; Thomas Agoritsas; Jerome Stirnemann; Herve Spechbach; Idris Guessous; Silvia Stringhini; Jerome Pugin; Pascale Roux-Lombard; Lionel Fontao; Claire-Anne Siegrist; Isabella Eckerle; Nicolas Vuilleumier; Laurent Kaiser

    doi:10.1101/2020.05.02.20080879 Date: 2020-05-06 Source: medRxiv

    Aims: To validate the diagnostic accuracy of a Euroimmun SARS-CoV-2 IgG and IgA immunoassay SERO for COVID-19 disease. Methods: In this unmatched (1:1) case-control validation study, we used sera of 181 laboratory-confirmed SARS-CoV-2 cases and 176 negative controls collected before the emergence of SARS-CoV-2. Diagnostic accuracy of the immunoassay SERO was assessed against a whole spike protein-based recombinant immunofluorescence assay (rIFA) by receiver operating characteristic (ROC) analyses. Discrepant cases between ELISA SERO and rIFA were further tested by pseudo-neutralization assay. Results: COVID-19 patients were more likely to be male TRANS and older than controls, and 50.3% of them were hospitalized. ROC curve analyses indicated that IgG and IgA had a high diagnostic accuracy with AUCs of 0.992 (95% Confidence Interval [95%CI]: 0.986-0.996) and 0.977 (95%CI: 0.963-0.990), respectively. IgG assays outperformed IgA assays (p=0.008). Considering optimized cut-offs taking the 15% inter-assay imprecision assessed into account, an IgG ratio cut-off > 1.5 displayed a 100% specificity (95%CI: 98-100) and a 100% positive predictive value SERO (95%CI: 97-100). A 0.5 cut-off displayed a 97% sensitivity SERO (95%CI: 93-99) and a 97% negative predictive value SERO (95%CI: 93-99). Adopting these thresholds, rather than those of the manufacturer, improved assay performance SERO, leaving 12% of IgG ratios ranging between 0.5-1.5 as indeterminate. Conclusions: The Euroimmun assay displays a nearly optimal diagnostic accuracy using IgG against SARS-CoV-2 in a samples of patients, without any obvious gains from considering IgA serology. The optimized cut-offs are fit for rule-in and rule-out purposes, allowing determination of whether individuals have been exposed to SARS-CoV-2 or not in our study population. They should however not be considered as a surrogate of protection at this stage.

    Repeated seroprevalence SERO of anti-SARS-CoV-2 IgG antibodies SERO in a population-based sample from Geneva, Switzerland

    Authors: Silvia Stringhini; Ania Wisniak; Giovanni Piumatti; Andrew S Azman; Stephen A Lauer; Helene Baysson; David De Ridder; Dusan Petrovic; Stephanie Schrempft; Kailing Marcus; Isabelle Arm-Vernez; Sabine Yerly; Olivia Keiser; Samia Hurst; Klara Posfay-Barbe; Didier Trono; Didier Pittet; Laurent Getaz; Francois Chappuis; Isabella Eckerle; Nicolas Vuilleumier; Benjamin Meyer; Antoine Flahault; Laurent Kaiser; Idris Guessous

    doi:10.1101/2020.05.02.20088898 Date: 2020-05-06 Source: medRxiv

    Background: Assessing the burden of COVID-19 based on medically-attended case counts is suboptimal given its reliance on testing strategy, changing case definitions and the wide spectrum of disease presentation. Population-based serosurveys provide one avenue for estimating infection MESHD rates and monitoring the progression of the epidemic, overcoming many of these limitations. Methods: Taking advantage of a pool of adult TRANS participants from population-representative surveys conducted in Geneva, Switzerland, we implemented a study consisting of 8 weekly serosurveys among these participants and their household members older than 5 years. We tested each participant for anti-SARS-CoV-2- IgG antibodies SERO using a commercially available enzyme-linked immunosorbent assay SERO (Euroimmun AG, Lubeck, Germany). We estimated seroprevalence SERO using a Bayesian regression model taking into account test performance SERO and adjusting for the age TRANS and sex of Geneva's population. Results: In the first three weeks, we enrolled 1335 participants coming from 633 households, with 16% <20 years of age TRANS and 53.6% female TRANS, a distribution similar to that of Geneva. In the first week, we estimated a seroprevalence SERO of 3.1% (95% CI 0.2-5.99, n=343). This increased to 6.1% (95% CI 2.6-9.33, n=416) in the second, and to 9.7% (95% CI 6.1-13.11, n=576) in the third week. We found that 5-19 year-olds (6.0%, 95% CI 2.3-10.2%) had similar seroprevalence SERO to 20-49 year olds (8.5%, 95%CI 4.99-11.7), while significantly lower seroprevalence SERO was observed among those 50 and older (3.7%, 95% CI 0.99-6.0, p=0.0008). Interpretation: Assuming that the presence of IgG antibodies SERO is at least in the short-term associated with immunity, these results highlight that the epidemic is far from burning out simply due to herd immunity. Further, no differences in seroprevalence SERO between children TRANS and middle age TRANS adults TRANS are observed. These results must be considered as Switzerland and the world look towards easing restrictions aimed at curbing transmission TRANS.

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MeSH Disease
Human Phenotype

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