A case of extremely prolonged viral shedding: Could cell cultures be a diagnostic tool to drive COVID-19 patient discharge?

Mileto, Davide; Foschi, Antonella; Mancon, Alessandro; Merli, Stefania; Staurenghi, Federica; Pezzati, Laura; Rizzo, Alberto; Conti, Federico; Romeri, Francesca; Bernacchia, Dario; R, Meroni; Rizzardini, Giuliano; Gismondo, Maria Rita; Micheli, Valeria

doi:10.1016/j.ijid.2020.11.161

Cited by 11 publications

(11 citation statements)

References 11 publications

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“…According to the kit specifications and our analysis, the analytical sensitivity of the Liferiver RT-PCR, used in our study, is 10 3 copies/mL using the QIAmp RNA extraction method; which aligns with the values obtained for the majority of amplification methods [ 15 , 16 , 30 , 31 ]. Long-term shedders of SARS-CoV-2 could experience higher and lower viral loads depending on the day of collection, but the general trend is that higher viral loads are required for isolation, although infectivity cannot be totally ruled out based on Vero cells’ infection only [ 32 , 33 ]. From our experience and from a meta-analysis, the chances of culturing SARS-CoV-2 from swabs when the RT-PCR Ct value of the specimen is >25 is very low (unpublished observations) [34] .…”

Section: Discussionmentioning

confidence: 99%

Diagnostic performance of a colorimetric RT -LAMP for the identification of SARS-CoV-2: A multicenter prospective clinical evaluation in sub-Saharan Africa

Baba¹,

Bitew²,

Fokam³

et al. 2021

EClinicalMedicine

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Background Management and control of the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus SARS-CoV-2 is critically dependent on quick and reliable identification of the virus in clinical specimens. Detection of viral RNA by a colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a simple, reliable and cost-effective assay, deployable in resource-limited settings (RLS). Our objective was to evaluate the intrinsic and extrinsic performances of RT-LAMP in RLS. Methods This is a multicenter prospective observational study of diagnostic accuracy, conducted from October 2020 to February 2021 in four African Countries: Cameroon, Ethiopia, Kenya and Nigeria; and in Italy. We enroled 1657 individuals who were either COVID-19 suspect cases, or asymptomatic and presented for screening. RNA extracted from pharyngeal swabs was tested in parallel by a colorimetric RT-LAMP and by a standard real time polymerase chain reaction (RT-PCR). Findings The sensitivity and specificity of index RT LAMP compared to standard RT-PCR on 1657 prospective specimens from infected individuals was determined. For a subset of 1292 specimens, which underwent exactly the same procedures in different countries, we obtained very high specificity (98%) and positive predictive value (PPV = 99%), while the sensitivity was 87%, with a negative predictive value NPV = 70%, Stratification of RT-PCR data showed superior sensitivity achieved with an RT-PCR cycle threshold (Ct) below 35 (97%), which decreased to 60% above 35. Interpretation In this field trial, RT-LAMP appears to be a reliable assay, comparable to RT-PCR, particularly with medium-high viral loads (Ct < 35). Hence, RT-LAMP can be deployed in RLS for timely management and prevention of COVID-19, without compromising the quality of output.

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Section: Discussionmentioning

confidence: 99%

Diagnostic performance of a colorimetric RT -LAMP for the identification of SARS-CoV-2: A multicenter prospective clinical evaluation in sub-Saharan Africa

Baba¹,

Bitew²,

Fokam³

et al. 2021

EClinicalMedicine

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“…Due to the high sensitivity of the qPCR assays, a very low number of virus genes can be detected, and SARS-CoV-2 RNA can be present in different body fluids for prolonged periods of time [7] . However, presence of virus genes does not translate into infectivity of the person, and studies have shown RNA positive samples to be negative for infectivity, particularly after longer time of shedding [ 8 , 9 ]. A previous study further observed that no respiratory samples with a SARS-CoV-2 qPCR Ct-value >24 showed infectivity in cell-culture [10] .…”

Section: Introductionmentioning

confidence: 99%

SARS-CoV-2 rapid antigen test: High sensitivity to detect infectious virus

Nordgren

Sharma

Olsson

et al. 2021

Journal of Clinical Virology

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Background The COVID-19 pandemic has highlighted the need for rapid, cost effective and easy-to-use diagnostic tools for SARS-CoV-2 infections that can be used in point of care settings to limit disease transmission. Objective We evaluated two rapid antigen immunochromatographic tests, Abbott Panbio™ COVID-19 Ag Rapid Test (Panbio) and Zhejiang Orient Gene/Healgen Biotech Coronavirus Ag rapid test cassette (Orient gene) for detection of infectious SARS-CoV-2. Results The tests were evaluated on nasopharyngeal samples taken from individuals having respiratory and/or COVID-19 related symptoms, which had been analyzed for SARS-CoV-2 RNA using real-time PCR. In total 156 PCR-positive, and 130 (Panbio) and 176 (Orient Gene) PCR-negative samples were analyzed. Overall sensitivity and specificity were 71.8% and 100% for Panbio and 79.5% and 74.4% for the Orient Gene test respectively. The false positives by the Orient Gene test were verified as SARS-CoV-2 negative by in-house real-time PCR assay and were negative for the four seasonal coronaviruses. Subgroup analysis revealed that the antigen tests had high sensitivity for samples with Ct-values <25 (>88%) and for samples containing infectious viruses as determined by cultivation on Vero cells, 94.1% and 97.1% for the Panbio and Orient gene tests, respectively. Furthermore, both tests had a sensitivity of <50 picogram for nucleocapsid protein. No sample with a Ct-value >27 was shown to contain infectious virus. Conclusion The results indicate that the rapid antigen tests, especially the Panbio tests may be a valuable tool to detect contagious persons during the ongoing pandemic.

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“…Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is usually self-limiting. However, several evidences suggest the possibility of prolonged viral shedding and re-infection, giving rise to doubt on transmission potential and immunity protection [ 1 , 2 ]. Here we report the case of SARS-CoV-2 evolution and re-emergence three months after recovery presenting prolonged absence of humoral response and high production of virus-induced IFN-γ.…”

Section: Lettermentioning

confidence: 99%

Viro-immunological evaluation in an immunocompromised patient with long-lasting SARS-CoV-2 infection

Mancon

Rizzo

Mileto

et al. 2022

Emerging Microbes & Infections

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A case of extremely prolonged viral shedding: Could cell cultures be a diagnostic tool to drive COVID-19 patient discharge?

Cited by 11 publications

References 11 publications

Diagnostic performance of a colorimetric RT -LAMP for the identification of SARS-CoV-2: A multicenter prospective clinical evaluation in sub-Saharan Africa

Diagnostic performance of a colorimetric RT -LAMP for the identification of SARS-CoV-2: A multicenter prospective clinical evaluation in sub-Saharan Africa

SARS-CoV-2 rapid antigen test: High sensitivity to detect infectious virus

Viro-immunological evaluation in an immunocompromised patient with long-lasting SARS-CoV-2 infection

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