Viral Load Difference between Symptomatic and Asymptomatic COVID-19 Patients: Systematic Review and Meta-Analysis

Zuin, Marco; Gentili, Valentina; Cervellati, Carlo; Rizzo, Roberta; Zuliani, Giovanni

doi:10.3390/idr13030061

Cited by 43 publications

(27 citation statements)

References 25 publications

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“…Rapid PCR-based SARS-CoV-2 detection is particularly important in high-frequency testing settings which is often associated with asymptomatic routine testing at workplaces or schools. Our data demonstrate no difference in viral loads between the asymptomatic and symptomatic individuals (Figure 2B-C), in line with previous studies 28 . Several studies have also evaluated the use of RT loop-mediated isothermal amplification (RT-LAMP) in saliva samples for fast detection of SARS-CoV-2.…”

Section: Discussionsupporting

confidence: 93%

Clinical Performance of Direct RT-PCR Testing of Raw Saliva for Detection of SARS-CoV-2 in Symptomatic and Asymptomatic Individuals

Castillo-Bravo

Lucca

Lai

et al. 2022

Preprint

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RT-qPCR tests based on RNA extraction from nasopharyngeal swab samples are promoted as the “gold standard” for SARS-CoV-2 detection. However, self-collected saliva samples offer a non-invasive alternative more suited to high-throughput testing. This study evaluated the performance of TaqPath COVID-19 Fast PCR Combo Kit 2.0 assay for detection of SARS-CoV-2 in raw saliva relative to a lab-developed direct RT-qPCR test (SalivaDirect-based PCR) and a RT-qPCR test based on RNA extraction from NPS samples. Both samples were collected from symptomatic and asymptomatic individuals (N=615). Saliva samples were tested for SARS-CoV-2 using the TaqPath COVID-19 Fast PCR Combo Kit 2.0 and the SalivaDirect-based PCR, while RNA extracts from NPS samples were tested by RT-qPCR according to the Irish national testing system. The TaqPath™ COVID-19 Fast PCR detected SARS-CoV-2 in 52 saliva samples, of which 51 were also positive with the SalivaDirect-based PCR. 49 samples displayed concordant results with the NPS extraction-based method, while three samples were positive on raw saliva. Among the negative samples, 10 discordant cases were found with the TaqPath COVID-19 Fast PCR (PPA–85.7%; NPA–99.5%), when compared to the RNA extraction-based NPS method, performing similarly to the SalivaDirect-based PCR (PPA-87.5%; NPA-99.5%). The direct RT-qPCR testing of saliva samples shows high concordance with NPS extraction-based method for SARS-CoV-2 detection, providing a cost-effective and highly-scalable system for high-throughput COVID-19 rapid-testing.

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Section: Discussionsupporting

confidence: 93%

Clinical Performance of Direct RT-PCR Testing of Raw Saliva for Detection of SARS-CoV-2 in Symptomatic and Asymptomatic Individuals

Castillo-Bravo

Lucca

Lai

et al. 2022

Preprint

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“…Some meta analyses indicated no significant difference in viral load at the upper respiratory tract for symptomatic vs . asymptomatic individuals ( Walsh et al, 2020 ; Zuin et al, 2021 ), and levels of viral RNA in saliva are in general comparable to those found in NP swabs ( Butler-Laporte et al, 2021 ). This would suggest that the limit of detection of COV-ID matches and exceeds what is needed to detect viral RNA in saliva of infectious and potentially contagious individuals.…”

Section: Discussionmentioning

confidence: 55%

A LAMP sequencing approach for high-throughput co-detection of SARS-CoV-2 and influenza virus in human saliva

Warneford-Thomson

Shah

Lundgren

et al. 2022

eLife

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The COVID-19 pandemic has created an urgent need for rapid, effective, and low-cost SARS-CoV-2 diagnostic testing. Here, we describe COV-ID, an approach that combines RT-LAMP with deep sequencing to detect SARS-CoV-2 in unprocessed human saliva with a low limit of detection (5–10 virions). Based on a multi-dimensional barcoding strategy, COV-ID can be used to test thousands of samples overnight in a single sequencing run with limited labor and laboratory equipment. The sequencing-based readout allows COV-ID to detect multiple amplicons simultaneously, including key controls such as host transcripts and artificial spike-ins, as well as multiple pathogens. Here, we demonstrate this flexibility by simultaneous detection of 4 amplicons in contrived saliva samples: SARS-CoV-2, influenza A, human STATHERIN, and an artificial SARS calibration standard. The approach was validated on clinical saliva samples, where it showed excellent agreement with RT-qPCR. COV-ID can also be performed directly on saliva absorbed on filter paper, simplifying collection logistics and sample handling.

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“…Similar findings have also been reported recently (28,29). In contrast, some studies found no difference in viral load between the two groups (30,31,) while others found higher viral load among asymptomatic individuals (32,33). Higher sensitivity has been observed among individuals presenting in the early symptomatic phase of their infection (12,22,25–27,34–36).…”

Section: Discussionmentioning

confidence: 86%

Diagnostic accuracy of the Panbio™ COVID-19 Antigen rapid test device for SARS-CoV-2 detection in Kenya, 2021: A field evaluation

Irungu

Munyua

Ochieng

et al. 2022

Preprint

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Background: Accurate and timely diagnosis is essential in limiting the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Real-time reverse transcription-polymerase chain reaction (rRT-PCR), the reference standard, requires specialized laboratories, costly reagents, and a long turnaround time. Antigen rapid diagnostic tests (Ag RDTs) provide a feasible alternative to rRT-PCR since they are quick, relatively inexpensive, and do not require a laboratory. The WHO requires that Ag RDTs have a sensitivity ≥80% and specificity ≥97%. Methods: This evaluation was conducted at 11 health facilities in Kenya between March and July 2021. We enrolled persons of any age with respiratory symptoms and asymptomatic contacts of confirmed COVID-19 cases. We collected demographic and clinical information and two nasopharyngeal specimens from each participant for Ag RDT testing and rRT-PCR. We calculated the diagnostic performance of the Panbio™ Ag RDT against the US Centers for Disease Control and Prevention's (CDC) rRT-PCR test. Results: We evaluated the Ag RDT in 2,245 individuals where 551 (24.5%, 95% CI: 22.8-26.3%) tested positive by rRT-PCR. Overall sensitivity of the Ag RDT was 46.6% (95% CI: 42.4-50.9%), specificity 98.5% (95% CI: 97.8-99.0%), PPV 90.8% (95% CI: 86.8-93.9%) and NPV 85.0% (95% CI: 83.4-86.6%). Among symptomatic individuals, sensitivity was 60.6% (95% CI: 54.3-66.7%) and specificity was 98.1% (95% CI: 96.7-99.0%). Among asymptomatic individuals, sensitivity was 34.7% (95% CI 29.3-40.4%) and specificity was 98.7% (95% CI: 97.8-99.3%). In persons with onset of symptoms <5 days (594/876, 67.8%), sensitivity was 67.1% (95% CI: 59.2-74.3%), and 53.3% (95% CI: 40.0-66.3%) among those with onset of symptoms >7 days (157/876, 17.9%). The highest sensitivity was 87.0% (95% CI: 80.9-91.8%) in symptomatic individuals with cycle threshold (Ct) values ≤30. Conclusion: The overall sensitivity and NPV of the Panbio™ Ag RDT were much lower than expected. The specificity of the Ag RDT was high and satisfactory; therefore, a positive result may not require confirmation by rRT-PCR. The kit may be useful as a rapid screening tool for only symptomatic patients in high-risk settings with limited access to RT-PCR. A negative result should be interpreted based on clinical and epidemiological information and may require retesting by rRT-PCR.

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Viral Load Difference between Symptomatic and Asymptomatic COVID-19 Patients: Systematic Review and Meta-Analysis

Cited by 43 publications

References 25 publications

Clinical Performance of Direct RT-PCR Testing of Raw Saliva for Detection of SARS-CoV-2 in Symptomatic and Asymptomatic Individuals

Clinical Performance of Direct RT-PCR Testing of Raw Saliva for Detection of SARS-CoV-2 in Symptomatic and Asymptomatic Individuals

A LAMP sequencing approach for high-throughput co-detection of SARS-CoV-2 and influenza virus in human saliva

Diagnostic accuracy of the Panbio™ COVID-19 Antigen rapid test device for SARS-CoV-2 detection in Kenya, 2021: A field evaluation

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