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1.
J Med Virol ; 93(3): 1743-1747, 2021 03.
Article in English | MEDLINE | ID: covidwho-1196459

ABSTRACT

Since the first case of COVID-19 reported in late December of 2019 in Wuhan, China, the SARS-CoV-2 virus has caused approximately 20 million infections and 732 thousand deaths around the world by 11 August 2020. Although the pathogen generally infects the respiratory system, whether it is present in the bloodstream and whether it poses a threat to the blood supply during the period of the outbreak is of serious public concern. In this study, we used enzyme-linked immunosorbent assay (ELISA) to screen total antibodies against SARS-CoV-2 in 2199 blood donors, who had donated blood at the Guangzhou Blood Center during the epidemic. The Ig-reactive samples were further characterized for IgA, IgG, and IgM subtypes by ELISA and viral nucleic acid by real-time polymerase chain reaction. Among the 2199 plasma samples, seven were reactive under total antibodies' screening. Further testing revealed that none of them had detectable viral nucleic acid or IgM antibody, but two samples contained IgA and IgG. The IgG antibody titers of both positive samples were 1:16 and 1:4, respectively. Our results indicated a low prevalence of past SARS-CoV-2 infection in our blood donors, as none of the tests were positive for viral nucleic acid and only 2 out of 2199 (0.09%) of samples were positive for IgG and IgA. There would be a limited necessity for the implementation of such testing in blood screening in a COVID-19 low-risk area.


Subject(s)
Antibodies, Viral/blood , Blood Donors/statistics & numerical data , COVID-19/epidemiology , SARS-CoV-2/immunology , Adolescent , Adult , China , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , RNA, Viral/blood , Young Adult
2.
Acta Haematol ; 144(5): 580-584, 2021.
Article in English | MEDLINE | ID: covidwho-1194384

ABSTRACT

Recently, a significant cluster of pneumonia caused by a novel betacoronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) was described initially in China and then spread throughout the world. Like other coronaviridae, the viral transmission occurs mainly through droplets. In addition, the virus has been detected in different clinical specimens, suggesting a potential transmission by other routes, including blood transfusion. However, the potential risk of transmission of SARS-CoV-2 via blood products is still unclear. The aim of our study was to investigate the prevalence of antibodies against SARS-CoV-2 among blood donors from South-Eastern Italy. Moreover, in the seropositive donors, we searched for the presence of the virus in nasopharyngeal swabs and in plasma samples. Overall, 1,797 blood donors from the Apulia region were tested for anti-SARS-CoV-2 antibodies, using a commercially available assay. Only 18/1,797 donors (1.0%) tested positive for anti-SARS-CoV-2 antibodies; in none of them SARS-CoV-2 viral RNA was detected in nasopharyngeal swabs and in plasma samples. Our results indicate that most of the blood donors in Apulia remained uninfected during this wave of the pandemic; further, none had detectable virus both in nasopharyngeal swabs and in blood samples. The risk to carry and transmit the virus by healthy and asymptomatic blood donors is probably very low.


Subject(s)
Antibodies, Viral/blood , Blood Donors , COVID-19/pathology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , COVID-19/virology , Female , Humans , Italy , Male , Middle Aged , Nasopharynx/virology , RNA, Viral/analysis , RNA, Viral/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Viral Load , Young Adult
3.
Diagnostics (Basel) ; 11(1)2021 Jan 06.
Article in English | MEDLINE | ID: covidwho-1067692

ABSTRACT

Serological assays can contribute to the estimation of population proportions with previous immunologically relevant contact with the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) virus. In this study, we compared five commercially available diagnostic assays for the diagnostic identification of SARS-CoV-2-specific antibodies. Depending on the assessed immunoglobulin subclass, recorded sensitivity ranged from 17.0% to 81.9% with best results for immunoglobulin G. Specificity with blood donor sera ranged from 90.2% to 100%, with sera from EBV patients it ranged from 84.3% to 100%. Agreement from fair to nearly perfect was recorded depending on the immunoglobulin class between the assays, the with best results being found for immunoglobulin G. Only for this immunoglobulin class was the association between later sample acquisition times (about three weeks after first positive PCR results) and positive serological results in COVID-19 patients confirmed. In conclusion, acceptable and comparable reliability for the assessed immunoglobulin G-specific assays could be shown, while there is still room for improvement regarding the reliability of the assays targeting the other immunoglobulin classes.

4.
Diagnostics (Basel) ; 11(1)2021 Jan 06.
Article in English | MEDLINE | ID: covidwho-1011437

ABSTRACT

Serological assays can contribute to the estimation of population proportions with previous immunologically relevant contact with the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) virus. In this study, we compared five commercially available diagnostic assays for the diagnostic identification of SARS-CoV-2-specific antibodies. Depending on the assessed immunoglobulin subclass, recorded sensitivity ranged from 17.0% to 81.9% with best results for immunoglobulin G. Specificity with blood donor sera ranged from 90.2% to 100%, with sera from EBV patients it ranged from 84.3% to 100%. Agreement from fair to nearly perfect was recorded depending on the immunoglobulin class between the assays, the with best results being found for immunoglobulin G. Only for this immunoglobulin class was the association between later sample acquisition times (about three weeks after first positive PCR results) and positive serological results in COVID-19 patients confirmed. In conclusion, acceptable and comparable reliability for the assessed immunoglobulin G-specific assays could be shown, while there is still room for improvement regarding the reliability of the assays targeting the other immunoglobulin classes.

5.
Eur J Microbiol Immunol (Bp) ; 10(3): 178-185, 2020 Sep 25.
Article in English | MEDLINE | ID: covidwho-801161

ABSTRACT

INTRODUCTION: To efficiently monitor the COVID-19 pandemic for surveillance purposes, reliable serological rapid diagnostic tests (RDTs) are desirable for settings where well-established high-throughput bench-top solutions are not available. Here, we have evaluated such an RDT. METHODS: We have assessed the Xiamen AmonMed Biotechnology COVID-19 IgM/IgG test kit (Colloidal gold) and the EUROIMMUN benchtop assay with serum samples from patients with polymerase chain reaction (PCR)-confirmed COVID-19 disease. Samples from patients with Epstein-Barr-virus (EBV) infection and blood donors were used for specificity testing. RESULTS: For the colloid gold rapid test and the EUROIMMUN assay, the study indicated overall sensitivity of 15.2% and 67.4%, respectively, while specificity of 99.0% and 97.9% with the blood donor sera, as well as 100% and 96.8% with the EBV-patients, were observed, respectively. An association of the time period between positive PCR results and serum acquisition with serological test positivity could be observed for the immunologlobulin G subclass of the EUROIMMUN assay only. CONCLUSIONS: In spite of acceptable specificity of the assessed RDT, the detected poor sensitivity leaves room for improvement. The test results remain difficult to interpret and therefore the RDT can currently not be recommended for routine diagnostic or surveillance use.

6.
Antiviral Res ; 181: 104880, 2020 09.
Article in English | MEDLINE | ID: covidwho-645374

ABSTRACT

We investigated the distribution of antibodies neutralizing SARS-CoV-2 according to age, sex or blood group in French blood donors. In 464 samples collected before the emergence of SARS-CoV-2 (2017 and 2018), our virus neutralization assay had a 100% specificity. It was used to test 998 samples collected from blood donors during the last week of March or the first week of April 2020. As expected at this stage of the outbreak, the prevalence was low (2.7%) and, importantly, criteria for blood donation imply that the vast majority of seropositives had asymptomatic or pauci-symptomatic SARS-CoV-2 infections. Seroprevalence values did not differ significantly among age groups (but were slightly higher in donors <30yo and ≥60yo), and between males and females (2.82% vs 2.69%), unlike what has been observed regarding hospitalizations admission to ICU and death rates in France. By contrast, we observed that the proportion of seropositives was significantly lower in group O donors (1.32% vs 3.86% in other donors, p = 0.014). We conclude that virus infection seems to occur with a similar incidence in men and women among French blood donors, but that blood group O persons are less at risk of being infected and not only of suffering from severe clinical presentations, as previously suggested.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/virology , Pneumonia, Viral/virology , Adult , Blood Donors , Blood Group Antigens , COVID-19 , Coronavirus Infections/epidemiology , Female , France/epidemiology , Hospitalization , Humans , Incidence , Intensive Care Units , Male , Middle Aged , Pandemics , Pneumonia, Viral/epidemiology , Risk , SARS-CoV-2 , Sensitivity and Specificity , Seroepidemiologic Studies , Young Adult
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