First report on qualitative detection of anti-COVID-19 antibody IgM and IgG in a short series of 98 subjects, healthcare workers and patients, by use an ELISA assay

Objective: The aim is to perform a preliminary testing about the presence of anti-COVID-19 IgM and IgG in a short series of healthcare workers and patients at SS. Antonio e Biagio e Cesare Arrigo Hospital, in Alessandria. Methods: Healthcare workers voluntarily agreed to perform the analysis. For patients, serological test was performed at clinician’s discretion. Detection of anti-COVID-19 IgM and IgG was performed separately by use ELISA assay. In order to perform a comparison age, sex, onset symptoms, RT-PCR result were collected. Results: Serological findings showed that most people with positive SARS-CoV-2 RT-PCR testing developed anti-SARS-CoV-2 IgG 14 days after the date of rhinopharyngeal swab and that anti-SARS-CoV-2 IgG detection was also observed in patients with negative RT-PCR. No anti-SARS-CoV-2 IgM was found. Conclusions: Serological testing may be useful to confirm a previous contact with SARS-CoV-2, but it cannot be used in diagnostics. They need further evidence on its performance and operational utility. At the current state of technological evolution, SARS-CoV-2 IgM and IgG antibodies serological tests can be used to supplement the viral RNA detenction by use RT-PCR.

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COVID-19 serological testing for Healthcare Workers in Lombardy, Italy

European Journal of Public Health ◽

10.1093/eurpub/ckaa165.351 ◽

2020 ◽

Vol 30 (Supplement_5) ◽

Author(s):

G Del Castillo ◽

A Castrofino ◽

F Grosso ◽

A Barone ◽

L Crottogini ◽

...

Keyword(s):

Healthcare Workers ◽

Geographical Area ◽

Healthcare Facility ◽

Nasopharyngeal Swab ◽

Infection Prevalence ◽

Serological Testing ◽

Prevention Policy ◽

Rt Pcr ◽

Serological Tests ◽

Screening Process

Abstract Issue COVID-19 pandemic began in Italy on February 20th, 2020. Since the beginning of the emergency Healthcare Workers' (HCWs) involvement was prominent, mainly due to direct assistance to COVID-19 patients. Therefore, we implemented a prevention policy for HCW screening through serological and RT-PCR testing. Description of the problem HCW screening for SARS-CoV-2 infection is essential for prevention and control of the pandemic. Lombardy's Healthcare authorities settled a screening process for HCWs divided into three steps: 1) body temperature assessment at the beginning and the end of work shift, if fever > 37.5 °C was present the HCW was sent back home and a nasopharyngeal swab was performed; 2) progressive recruitment for serological testing; 3) on those positive to IgG a nasopharyngeal swab was performed and tested for viral RNA by RT-PCR. Results Among 79185 HCW tested, 9589 (12%) were positive on serological IgG testing. Of the 9589 positive a nasopharyngeal swab was performed on 6884. Of these 358 (5%) tested positive and the remaining 6526 (95%) negative to RT-PCR. We calculated a Positive Predictive Value of 5.2%. The rate of positive serological tests for each Healthcare facility varied between 0% and 78%. Five percent of all facilities, belonging to Brescia, Bergamo and Cremona area, reported a positivity rate higher than 40% in HCWs. A second cluster (18% of all facilities), involving the same geographical area, reported a rate between 20% and 40%, whereas the remaining facilities (76%) of the region a rate <20%. Lessons Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs especially in a high infection prevalence setting. Key messages Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs. Infection prevention in HCW may benefit from a screening campaign especially in high prevalence settings.

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Importance of serological testing in the convalescence phase in patients with pulmonary impairment due to COVID 19 - a health care workers analysis

10.1101/2021.03.24.20208835 ◽

2021 ◽

Author(s):

José Rodrigues Pereira ◽

Ilka Lopes Santoro ◽

Maria Silvia Biagioni Santos ◽

Andreia Padilha de Toledo ◽

Greice Elen Copelli ◽

...

Keyword(s):

Serological Test ◽

Rt Pcr ◽

Serological Tests ◽

Care Workers ◽

Pulmonary Impairment ◽

Increased Sensitivity ◽

Pulmonary Changes ◽

The Subject ◽

Convalescence Phase ◽

The Ideal

1AbstractSince its discovery, more than 37 million people have been infected by SARS-CoV-2 with deaths around 1 million worldwide. The prevalence is not known because infected individuals may be asymptomatic. In addition, the use of specific diagnostic tests is not always conclusive, raising doubts about the etiology of the disease.The best diagnostic method and the ideal time of collection remains the subject of study. The gold standard for diagnosing COVID 19 is the RT PCR molecular test, usually using an oropharynx and nasopharynx swab. Its sensitivity is 70% and drops significantly after the second week of symptoms. Serological tests, in turn, have increased sensitivity after 14 days, and can contribute to the diagnosis when SARS-CoV-2 infection is suspected, even with negative RT PCR.Our study showed sensitivity and specificity of 100% of the serological test (ELISA method) for cases of viral pneumonia caused by the new coronavirus, suggesting that this test could assist in the diagnosis of pulmonary interstitial changes that have not yet been etiologically clarified. We found a greater immune response in men, regardless of the severity of symptoms. The greater the severity, the higher the levels of IgA and IgG, mainly found in patients with multilobar impairment and in need for oxygen. We concluded that the serological test collected around 30 days after the onset of symptoms is the best diagnostic tool in the convalescence phase, not only for epidemiological purposes, but also for the etiological clarification of pulmonary changes that have not yet been diagnosed.

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Sero-prevalence of anti-SARS-CoV-2 Antibodies in Addis Ababa, Ethiopia

10.1101/2020.10.13.337287 ◽

2020 ◽

Author(s):

Berhanu Nega Alemu ◽

Adamu Addissie ◽

Gemechis Mamo ◽

Negussie Deyessa ◽

Tamrat Abebe ◽

...

Keyword(s):

Serological Test ◽

Addis Ababa ◽

Rapid Test ◽

Cross Sectional Study ◽

Rt Pcr ◽

Serological Tests ◽

Cross Sectional ◽

History Of ◽

Community Transmission ◽

Pcr Test

AbstractBackgroundAnti-SARS-CoV-2 antibody tests are being increasingly used for sero-epidemiological purposes to provide better understanding of the extent of the infection in the community, and monitoring the progression of the COVID-19 epidemic. We conducted sero-prevalence study to estimate prior infection with with SARS-CoV-2 in Addis Ababa.MethodsA cross-sectional study was done from April 23 to 28, 2020 among 301 randomly selected residents of Addis Ababa; with no known history of contact with confirmed COVID-19 person. Interviews on socio demographic and behavioural risk factor followed by serological tests were performed for SARS-CoV-2 IgM, and IgG antibodies, using COVID-19 IgG/IgM Rapid Test Cassette. The test has sensitivity of 87·9% and specificity of 100% for lgM; and a sensitivity of 97·2% and specificity of 100% for IgG. RT-PCR test was also done on combined nasopharyngeal and oropharengeal swabs as an important public health consideration.FindingsThe unadjusted antibody-based crude SARS-CoV-2 prevalence was 7·6% and the adjusted true SARS-CoV-2 prevalence was estimated at 8·8% (95% CI 5·5%-11·6%) for the study population. Higher sero-prevalence were observed for males (9.0%), age below 50 years (8.2%), students and unemployed (15.6%), those with primary education (12.1%), smokers (7.8%), alcohol consumers (8.6%), chatt-chewers (13.6%) and shish smokers (18.8%). Seroprevalence was not significantly associated neither with socio-demographic not behavioral characteristics. According to the findings, possibly more individuals had been infected in Addis Ababa than what was being detected and reported by RT-PCR test suggestive of community transmission. The use of serological test for epidemiological estimation of the extent of SARS-CoV-2 epidemic gives a more precise estimate of magnitude which would be used for further monitoring and surveillance of the magnitude of the SARS CoV-2 infection.

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RAPID SEROLOGICAL TESTS HAVE A ROLE IN ASYMPTOMATIC HEALTH WORKERS COVID-19 SCREENING

10.1101/2020.04.15.20057786 ◽

2020 ◽

Cited By ~ 3

Author(s):

Angelo Virgilio Paradiso ◽

SimonaDe Summa ◽

Nicola Silvestris ◽

Stefania Tommasi ◽

Antonio Tufaro ◽

...

Keyword(s):

High Risk ◽

Cancer Patients ◽

Health Workers ◽

Serological Test ◽

Analytical Sensitivity ◽

Rt Pcr ◽

Serological Tests ◽

Clinical Meaning ◽

Asymptomatic Subjects

AbstractHealth workers are at high risk for SARS-CoV-2 infection and, if asymptomatic, for transmitting the virus on to fragile cancer patients. We screened 525 health workers of our Cancer Institute with rapid serological test Viva-Diag analyzingCOVID-19 associated-IgG/IgM. Six subjects (1,1%) resulted with Viva-Diag test not-negative for IgM. All 6 cases had RT-PCR SARS-CoV-2 test negative; repeating analysis ofIgG/IgM expression by CLIA assay also, 2 cases resulted IgM positive and 1 case IgG/IgM positive. This latter subject reported a contact with an infected SARS-CoV-2 person, a month earlier.In conclusion our study seems to suggest: a) a different analytical sensitivity inIgG/IgM evaluation for Viva-Diag and CLIA assays needing to be further determined; b) the ability of Viva-Diagrapid COVID-19 test to evidence health workers positive for Immunoglobulins expression. Discordant results of rapid serological tests with respect to RT-PCR stress the different clinical meaning the two assays can have, question clearly referring to further studies to optimize the utilization of rapid serological test in asymptomatic subjects at high risk for infection.

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Comparative analysis of three point-of-care lateral flow immunoassays for detection of anti-SARS-CoV-2 antibodies in COVID-19 confirmed healthcare workers

10.1101/2020.11.11.20229914 ◽

2020 ◽

Author(s):

Danielle Dias Conte ◽

Joseane Mayara Almeida Carvalho ◽

Luciano Kleber de Souza Luna ◽

Klinger Soares Faíco-Filho ◽

Ana Helena Perosa ◽

...

Keyword(s):

Healthcare Workers ◽

Large Scale ◽

Point Of Care ◽

Antibody Test ◽

Cost Effective ◽

Lateral Flow ◽

Rt Pcr ◽

Serum Samples ◽

Igg Antibody ◽

Serological Tests

AbstractSince the Coronavirus Disease 2019 (COVID-19) pandemic, Brazil has the third-highest number of confirmed cases and the second-highest number of recovered patients. SARS-CoV-2 detection by real-time RT-PCR is the gold standard in certified infrastructured laboratories. However, for large-scale testing, diagnostics should be fast, cost-effective, widely available, and deployed for the community, such as serological tests based on lateral flow immunoassay (LFIA) for IgM/IgG detection. We evaluated three different commercial point-of-care (POC) LFIAs for anti-SARS-CoV-2 IgM and IgG detection in capillary whole blood of 100 healthcare workers (HCW) previously tested by RT-PCR: 1) COVID-19 IgG/IgM BIO (Bioclin, Brazil), 2) Diagnostic kit for IgM/IgG Antibody to Coronavirus (SARS-CoV-2) (Livzon, China); and 3) SARS-CoV-2 Antibody Test (Wondfo, China). A total of 84 positives and 16 negatives HCW were tested. The data was also analyzed by the number of days post symptoms (DPS) in three groups: <30 (n=26), 30-59 (n=42), and >59 (n=16). Overall detection was 85.71%, 47.62%, and 44.05% for Bioclin, Livzon, and Wondfo, respectively, with a specificity of 100%, and 98.75% for Livzon on storage serum samples. Bioclin was more sensitive (p<0.01), regardless of the DPS. Thus, the Bioclin can be used as a POC test to monitor SARS-CoV-2 seroconversion in HCW.

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A brain cyst load-associated antigen is a Toxoplasma gondii biomarker for serodetection of persistent parasites and chronic infection

BMC Biology ◽

10.1186/s12915-021-00959-9 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Céline Dard ◽

Christopher Swale ◽

Marie-Pierre Brenier-Pinchart ◽

Dayana C. Farhat ◽

Valeria Bellini ◽

...

Keyword(s):

Toxoplasma Gondii ◽

Biomarker Discovery ◽

Serological Test ◽

Genetically Engineered ◽

Host Cells ◽

Elisa Assay ◽

Recombinant Polypeptide ◽

Serological Tests ◽

Past Infection ◽

Immune Balance

Abstract Background Biomarker discovery remains a major challenge for predictive medicine, in particular, in the context of chronic diseases. This is true for the widespread protozoan Toxoplasma gondii which establishes long-lasting parasitism in metazoans, humans included. This microbe successively unfolds distinct genetic programs that direct the transition from high to low replicative potential inside host cells. As a slow-replicating cell, the T. gondii bradyzoite developmental stage persists enclosed in a cyst compartment within tissues including the nervous system, being held by a sustained immune equilibrium which accounts for the prolonged clinically silent phase of parasitism. Serological surveys indicate that nearly one third of the human population has been exposed to T. gondii and possibly host bradyzoites. Because any disruption of the immune balance drives the reverse transition from bradyzoite to fast replicating tachyzoite and uncontrolled growth of the latter, these people are at risk for life-threatening disease. While serological tests for discriminating recent from past infection are available, there is yet no immunogenic biomarker used in the serological test to allow ascertaining the presence of persistent bradyzoites. Results Capitalizing on genetically engineered parasites induced to produce mature bradyzoites in vitro, we have identified the BCLA/MAG2 protein being restricted to the bradyzoite and the cyst envelope. Using laboratory mice as relevant T. gondii host models, we demonstrated that BCLA/MAG2 drives the generation of antibodies that recognize bradyzoite and the enveloping cyst structure. We have designed an ELISA assay based on a bacterially produced BCLA recombinant polypeptide, which was validated using a large collection of sera from mice of different genetic backgrounds and infected with bcla+ or bcla-null cystogenic and non-cystogenic T. gondii strains. To refine the design of the ELISA assay, we applied high-resolution BCLA epitope mapping and identified a specific combination of peptides and accordingly set up a selective and sensitive ELISA assay which allowed the detection of anti-BCLA/MAG2 antibodies in the sera of human patients with various forms of toxoplasmosis. Conclusions We brought proof of principle that anti-BCLA/MAG2 antibodies serve as specific and sensitive serological markers in the perspective of a combinatorial strategy for detection of persistent T. gondii parasitism.

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Waning of SARS-CoV-2 Antibody levels response to inactivated cellular vaccine over 6 months among healthcare workers

10.1101/2021.12.30.21268532 ◽

2022 ◽

Author(s):

Monica Taminato ◽

Ana Paula Cunha Chaves ◽

Richarlisson Borges de Morais ◽

Luiz Vinícius Leão Moreira ◽

Danielle Dias Conte ◽

...

Keyword(s):

Healthcare Workers ◽

Serological Test ◽

Demographic Data ◽

Humoral Response ◽

Igg Antibody ◽

Serological Tests ◽

Post Vaccination ◽

Age Cohorts ◽

Vaccine Booster ◽

Antibody Levels

Background Health Care workers (HCW) are an important group affected by this pandemic and COVID-19 has presented substantial challenges for health professionals and health systems in many countries. The Brazilian vaccination plan implemented in October, so that third dose for HCW. However, the persistence of CoronaVac vaccine-induced immunity is unknown, and immunogenicity according to age cohorts may differ among individuals. Objective Evaluate the post vaccination immune humoral response and the relationship between post-vaccination seropositivity rates and demographic data among Healthcare Workers over 6 months after CoronaVac immunization. Methods A cross section study including Healthcare professionals vaccinated with CoronaVac for 6 months or more. The study was carried with the analysis of post-vaccination serological test to assess the levels of humoral response after vaccination. Results 329 participants were included. Among them, 76% were female. Overall, 18.5% were positive quantitative titles (IQR 42.87-125.5) and the negative group was 80%, quantitative titles (IQR 5.50-13.92). Conclusion It was possible to identify a group with positive quantitative titles in serological test for IgG antibody against the SARS-CoV-2. Further investigation is required to determine the durability of post-vaccination antibodies and how serological tests can be determine the ideal timing of vaccine booster doses.

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Diagnosis of COVID-19 by Serology in Admitted Patients with Negative RT-PCR Assay

Iranian Journal of Allergy Asthma and Immunology ◽

10.18502/ijaai.v20i4.6949 ◽

2021 ◽

Author(s):

Mitra Rezaei ◽

Parvaneh Baghaei ◽

Makan Sadr ◽

Afshin Moniri ◽

Abdolreza Babamahmoodi ◽

...

Keyword(s):

Diagnostic Yield ◽

Serological Test ◽

False Negative ◽

Diagnostic Methods ◽

Rt Pcr ◽

Pcr Assay ◽

Serological Tests ◽

Negative Results ◽

False Negative Results ◽

Polymerase Chain

Considering the increasing prevalence and burden of coronavirus disease 2019 (COVID-19) disease and false-negative results in routine reverse transcription-polymerase chain reaction (RT-PCR) tests, additional diagnostic methods are needed to diagnose active cases of this disease. This prospective study was conducted on patients, in whom clinical and radiological symptoms/signs were in favor of COVID-19 while their first PCR test was negative. Later on, a second RT-PCR was performed and serological evaluation was carried out and results were compared with each other. Out of 707 patients who had been referred to the hospital and were clinically and radiologically suspicious of disease, 137 patients with negative RT-PCR tests entered the study. RT-PCR assay became positive for the second time in 45 (32.8%). Anti-COVID-19 IgM and IgG antibodies were positive in 83 (60.6%) and 86 (62.8%) patients, respectively. Finally, it was determined that serological test was diagnostic in 73% of patients and the diagnostic yield of serology was significantly higher after the first week of illness (54.8% in the first week and 88% after that). Taking advantage of both serological tests and RT-PCR helps in diagnosing 83.9% of cases. Based on the present study, the serology may be useful as a complementary test and in parallel to RT-PCR assay for diagnosis of COVID-19 among admitted symptomatic cases.

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Evaluating COVID-19 screening strategies based on serological tests

10.1101/2020.06.12.20129403 ◽

2020 ◽

Author(s):

Michela Baccini ◽

Alessandra Mattei ◽

Emilia Rocco ◽

Giulia Vannucci ◽

Fabrizia Mealli

Keyword(s):

Reproduction Number ◽

Serological Test ◽

Screening Strategy ◽

Antibody Detection ◽

Screening Procedure ◽

Rt Pcr ◽

False Negatives ◽

Serological Tests ◽

Reliable Technique ◽

Screening Strategies

ABSTRACTBackgroundFacing the SARS-CoV-2 epidemic requires intensive testing on the population to early identify and isolate infected subjects. Although RT-PCR is the most reliable technique to detect ongoing infections, serological tests are frequently proposed as tools in heterogeneous screening strategies. We analyze the performance of a screening strategy proposed in Tuscany (Italy), which first uses qualitative rapid tests for antibody detection, and then RT-PCR tests on the positive subjects.MethodsWe simulate the number of RT-PCR tests required by the screening strategy and the undetected ongoing infections in a pseudo-population of 500’000 subjects, under different prevalence scenarios and assuming a sensitivity of the serological test ranging from 0.50 to 0.80 (specificity=0.98). A compartmental model is used to predict the number of new infections generated by the false negatives two months after the screening, under different values of the infection reproduction number.ResultsAssuming a sensitivity equal to 0.80 and a prevalence of 0.3%, the screening procedure would require on average 11167.6 RT-PCR tests and would produce 300 false negatives, responsible after two months of a number of contagions ranging from 526 to 1132, under the optimistic scenario of a reproduction number between 0.5 to 1. Costs and false negatives increase with the prevalence.ConclusionsThe analyzed screening procedure should be avoided unless the prevalence and the rate of contagion are very low. The cost and effectiveness of the screening strategies should be evaluated in the actual context of the epidemic, accounting for the fact that it may change over time.

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Incidence of virus diseases in maize fields in the Trakya region of Turkey

Phytoprotection ◽

10.7202/015853ar ◽

2007 ◽

Vol 87 (3) ◽

pp. 115-122 ◽

Cited By ~ 5

Author(s):

Havva Ilbağı ◽

Frank Rabenstein ◽

Antje Habekuss ◽

Frank Ordon ◽

Ahmet Çıtır

Keyword(s):

Mosaic Virus ◽

Barley Yellow Dwarf Virus ◽

Serological Test ◽

Maize Dwarf Mosaic Virus ◽

Rt Pcr ◽

Virus Diseases ◽

Serological Tests ◽

Two Samples ◽

Maize Plants ◽

Yellow Dwarf Virus

Abstract A survey on maize virus diseases was conducted in the Trakya region of Turkey by examining 32 496 and 46 871 plants in 2004 and 2005, respectively. Rates of symptomatic plants were estimated at 3.7 to 63.6%, depending on locations. Biological and serological test results revealed the presence of barley yellow dwarf virus-PAV (BYDV-PAV), maize dwarf mosaic virus (MDMV), sugarcane mosaic virus (SCMV), and Johnson grass mosaic virus (JGMV). One hundred forty-two samples were collected randomly from 6492 symptomatic plants in 2004. Seventy-two out of the 142 samples were infected with MDMV, two were infected with BYDV-PAV, 19 with MDMV and BYDV-PAV, two with MDMV, BYDV-PAV and SCMV, and only one sample contained the four viruses. In 2005, 100 other leaf samples were collected randomly from 11 739 symptomatic maize plants. Serological tests revealed that 50% of the samples were infected with MDMV and SCMV; however, five showed mixed infections of two or three combinations of tested viruses. Individual MDMV, SCMV, BYDV-PAV and JGMV infections were detected in five, three, two and four samples, respectively. Presence of MDMV was confirmed by Western blot analysis and IC-RT-PCR. SCMV was also detected by IC-RT-PCR. This is the first study reporting the detection of SCMV and JGMV on maize plants in Turkey.

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