Persistence of SARS-CoV-2 Viral RNA in Nasopharyngeal Swabs after Death: An Observational Study

The aim of this study was to investigate the persistence of SARS-CoV-2 in post-mortem swabs of subjects who died from SARS-CoV-2 infection. The presence of the virus was evaluated post-mortem from airways of 27 SARS-CoV-2 positive patients at three different time points (T1 2 h; T2 12 h; T3 24 h) by real-time PCR. Detection of antibodies to SARS-CoV-2 was performed by Maglumi 2019-nCoV IgM/IgG chemiluminescence assay. SARS-CoV-2 viral RNA was still detectable in 70.3% of cases within 2 h after death and in 66,6% of cases up to 24 h after death. Our data showed an increase of the viral load in 78,6% of positive individuals 24 h post-mortem (T3) in comparison to that evaluated 2 h after death (T1). Noteworthy, we detected a positive T3 post-mortem swab (24 h after death) from 4 subjects who were negative at T1 (2 h after death). The results of our study may have an important value in the management of deceased subjects not only with a suspected or confirmed diagnosis of SARS-CoV-2, but also for unspecified causes and in the absence of clinical documentation or medical assistance.

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Persistence of SARS-CoV-2 Viral RNA in Nasopharyngeal Swabs after Death: An Observational Study

10.20944/preprints202103.0641.v1 ◽

2021 ◽

Author(s):

Francesca Servadei ◽

Silvestro Mauriello ◽

Manuel Scimeca ◽

Bartolo Caggiano ◽

Marco Ciotti ◽

...

Keyword(s):

Viral Load ◽

Observational Study ◽

Real Time ◽

Real Time Pcr ◽

Pcr Detection ◽

Viral Rna ◽

Clinical Documentation ◽

Post Mortem ◽

Medical Assistance ◽

Time Points

Background: The aim of this study was to investigate the persistence of SARS-CoV-2 in post-mortem swabs of subjects who died from SARS-CoV-2 infection. Methods: The presence of the virus was evaluated post-mortem from airways of 27 SARS-CoV-2 positive patients at three different time points (T1 2 hours; T2 12 hours – T3 24 hours) by real-time PCR. Detection of antibodies to SARS-CoV-2 was performed by Maglumi 2019-nCoV IgM/IgG chemiluminescence assay. Results: SARS-CoV-2 viral RNA was still detectable in 70,3% of cases within 2 hours after death and in 66,6% of cases up to 24 hours after death. Our data showed an increase of the viral load in 78,6% of positive individuals 24 hours post-mortem (T3) in comparison to that evaluated 2 hours after death (T1). Noteworthy, we detected a positive T3 post-mortem swab (24 hours after death) from 4 subjects who were negative at T1 (2 hours after death). Conclusion: The results of our study may have an important value in the management of deceased subjects not only with a suspected or confirmed diagnosis of SARS-CoV-2, but also for unspecified causes and in the absence of clinical documentation or medical assistance.

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Detection of SARS-CoV-2 RNA in nasopharyngeal swabs from COVID-19 patients and asymptomatic cases of infection by real-time and digital PCR

Russian Clinical Laboratory Diagnostics ◽

10.18821/0869-2084-2020-65-12-785-792 ◽

2020 ◽

Vol 65 (12) ◽

pp. 785-792

Author(s):

V. A. Ternovoi ◽

R. Yu. Lutkovsky ◽

E. P. Ponomareva ◽

A. V. Gladysheva ◽

E. V. Chub ◽

...

Keyword(s):

Viral Load ◽

Real Time ◽

Real Time Pcr ◽

Clinical Symptoms ◽

False Negative ◽

Digital Pcr ◽

Viral Rna ◽

Laboratory Research ◽

Low Concentration ◽

Negative Results

In this work we tested two reagent kits developed by us for detecting SARS-CoV-2 RNA using a fragment of the ORF1ab gene in digital PCR and real-time PCR formats. Data were obtained on the detection of SARS-CoV-2 virus RNA in nasopharyngeal swabs of patients with COVID-19 and asymptomatic carriers. The developed reagent kits provided 100% sensitivity and a detection limit of 103 GE / ml for qPCR, and at least 200 copies / ml of viral RNA when performing digital PCR. These methods were tested using a panel of 1,328 samples collected from patients with suspected COVID-19 at the beginning of 2020 in the Russian Federation. It has been shown that dPCR is more sensitive and can be used to analyze samples with low viral load, including those from patients without clinical symptoms. dPCR significantly improves the accuracy of laboratory research and significantly reduces the number of false negative results in the diagnosis of SARS-CoV-2. Determination of the concentration of SARS-CoV-2 RNA in patients with different clinical course of the disease showed that the concentration of viral RNA can sharply decrease in the first days of the disease. A low concentration of viral RNA in samples from patients is also characteristic of asymptomatic disease. Digital PCR provides a higher detection rate for asymptomatic cases, which is approximately 75% of those infected, as opposed to 45% for real-time PCR. The results obtained on the use of the digital PCR method for detecting SARS-CoV-2 RNA showed that this method is especially suitable for detecting RNA in case of its low concentration in contacts, as well as for monitoring changes in viral load in convalescent patients.

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