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3.
J Clin Virol ; 143: 104947, 2021 10.
Article in English | MEDLINE | ID: covidwho-1364218

ABSTRACT

Robust antigen point-of-care SARS-CoV-2 tests have been proposed as an efficient tool to address the COVID-19 pandemic. This requirement was raised after acknowledging the constraints that are brought by molecular biology. However, worldwide markets have been flooded with cheap and potentially underperforming lateral flow assays. Herein we retrospectively compared the overall performance of five qualitative rapid antigen SARS-CoV-2 assays and one quantitative automated test on 239 clinical swabs. While the overall sensitivity and specificity are relatively similar for all tests, concordance with molecular based methods varies, ranging from 75,7% to 83,3% among evaluated tests. Sensitivity is greatly improved when considering patients with higher viral excretion (Ct≤33), proving that antigen tests accurately distinguish infectious patients from viral shedding. These results should be taken into consideration by clinicians involved in patient triage and management, as well as by national authorities in public health strategies and for mass campaign approaches.


Subject(s)
COVID-19 , SARS-CoV-2 , Antigens, Viral , Humans , Nasopharynx , Pandemics , Retrospective Studies , Sensitivity and Specificity
5.
Sci Rep ; 11(1): 14977, 2021 07 22.
Article in English | MEDLINE | ID: covidwho-1322500

ABSTRACT

A comprehensive clinical and microbiological assessments of COVID-19 in front-line healthcare workers (HCWs) is needed. Between April 10th and May 28th, 2020, 319 HCWs with acute illness were reviewed. In addition to SARS-CoV-2 RT-PCR screening, a multiplex molecular panel was used for testing other respiratory pathogens. For SARS-CoV-2 positive HCWs, the normalized viral load, viral culture, and virus neutralization assays were performed weekly. For SARS-CoV-2 negative HCWs, SARS-CoV-2 serological testing was performed one month after inclusion. Among the 319 HCWs included, 67 (21.0%) were tested positive for SARS-CoV-2; 65/67 (97.0%) developed mild form of COVID-19. Other respiratory pathogens were found in 6/66 (9.1%) SARS-CoV-2 positive and 47/241 (19.5%) SARS-Cov-2 negative HCWs (p = 0.07). The proportion of HCWs with a viral load > 5.0 log10 cp/mL (Ct value < 25) was less than 15% at 8 days after symptom onset; 12% of HCWs were positive after 40 days (Ct > 37). More than 90% of cultivable virus had a viral load > 4.5 log10 cp/mL (Ct < 26) and were collected within 10 days after symptom onset. Among negative HCWs, 6/190 (3.2%) seroconverted. Our data suggest that the determination of viral load can be used for appreciating the infectiousness of infected HCWs. These data could be helpful for facilitating their return to work.


Subject(s)
COVID-19/diagnosis , Health Personnel , SARS-CoV-2/isolation & purification , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19 Nucleic Acid Testing , COVID-19 Serological Testing , Female , Humans , Male , Middle Aged , Prospective Studies , Viral Load , Young Adult
6.
J Clin Microbiol ; 59(4)2021 03 19.
Article in English | MEDLINE | ID: covidwho-1177519

ABSTRACT

The COVID-19 pandemic, caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread worldwide. Serological testing for SARS-CoV-2-specific antibodies plays an important role in understanding and controlling the pandemic, notably through epidemiological surveillance. Well-validated and highly specific SARS-CoV-2 serological assays are urgently needed. We describe here the analytical and clinical performance of Vidas SARS-CoV-2 IgM and Vidas SARS-CoV-2 IgG, two CE-marked, emergency use authorization (EUA)-authorized, automated, qualitative assays for the detection of SARS-CoV-2-specific IgM and IgG, respectively. Both assays showed high within-run and within-laboratory precision (coefficients of variation < 11.0%) and very low cross-reactivity toward sera of patients with a past common coronavirus or respiratory virus infection. Clinical specificity determined on up to 989 prepandemic healthy donors was ≥99% with a narrow 95% confidence interval for both IgM and IgG assays. Clinical sensitivity was determined on up to 232 samples from 130 reverse transcriptase PCR (RT-PCR)-confirmed SARS-CoV-2 patients. The positive percent agreement (PPA) with SARS-CoV-2 PCR reached 100% at ≥16 days (Vidas SARS-CoV-2 IgM) and ≥32 days (Vidas SARS-CoV-2 IgG) of symptom onset. Combined IgM/IgG test results improved the PPA compared to each test alone. SARS-CoV-2 IgG seroconversion followed closely that of SARS-CoV-2 IgM and remained stable over time, while SARS-CoV-2 IgM levels rapidly declined. Interestingly, SARS-CoV-2-specific IgM and IgG responses were significantly higher in COVID-19 hospitalized versus nonhospitalized patients. Altogether, the Vidas SARS-CoV-2 IgM and IgG assays are highly specific and sensitive serological tests suitable for the reliable detection of past acute SARS-CoV-2 infections.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Humans , Immunoglobulin G , Immunoglobulin M , Pandemics , Sensitivity and Specificity
7.
Clin Exp Allergy ; 51(7): 947-950, 2021 07.
Article in English | MEDLINE | ID: covidwho-1153430

ABSTRACT

Acute attacks could occur during the convalescent phase of COVID-19 illness, more commonly in patients with a history of frequent attacks. However it is unclear whether the acute attacks during the convalescent phase are specifically triggered by COVID-19 or not.


Subject(s)
Angioedemas, Hereditary , COVID-19/metabolism , Registries , Adult , Aged , Aged, 80 and over , Angioedemas, Hereditary/blood , Angioedemas, Hereditary/epidemiology , Angioedemas, Hereditary/therapy , COVID-19/blood , COVID-19/epidemiology , COVID-19/therapy , Female , Humans , Male , Middle Aged , SARS-CoV-2
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