scholarly journals Age and Sex Modulate SARS-CoV-2 Viral Load Kinetics: A Longitudinal Analysis of 1735 Subjects

2021 ◽  
Vol 11 (9) ◽  
pp. 882
Author(s):  
Valerio Caputo ◽  
Andrea Termine ◽  
Carlo Fabrizio ◽  
Giulia Calvino ◽  
Laura Luzzi ◽  
...  
Keyword(s):  
Viral Load ◽  
Healthcare Professionals ◽  
High Viral Load ◽  
Digital Pcr ◽  
Original Strain ◽  
Rt Pcr ◽  
Subgenomic Rna ◽  
Slow Decay ◽  
Male Sex ◽  
Age And Sex

The COVID-19 pandemic caused by SARS-CoV-2 represents a public health emergency, which became even more challenging since the detection of highly transmissible variants and strategies against COVID-19 were indistinctly established. We characterized the temporal viral load kinetics in individuals infected by original and variant strains. Naso-oropharyngeal swabs from 33,000 individuals (admitted to the IRCCS Santa Lucia Foundation Drive-in, healthcare professionals and hospitalized patients who underwent routinary screening) from November 2020 to June 2021 were analyzed. Of them, 1735 subjects were selected and grouped according to the viral strain. Diagnostic analyses were performed by CE-IVD RT-PCR-based kits. The subgenomic-RNA component was assessed in 36 subjects using digital PCR. Infection duration, viral load decay speed, effects of age and sex were assessed and compared by extensive statistical analyses. Overall, infection duration and viral load differed between the groups (p < 0.05). Male sex was more present among both original and variant carriers affected with high viral load and showing fast decay speed, whereas original strain carriers with slow decay speed resulted in older (p < 0.05). Subgenomic-RNA was detected in the positive samples, including those with low viral load. This study provides a picture of the viral load kinetics, identifying individuals with similar patterns and showing differential effects of age and sex, thus providing potentially useful information for personalized management of infected subjects.

scholarly journals Prolonged Detection of SARS CoV2 RNA in Extracellular Vesicles in Nasal Swab RT-PCR Negative Patients

2021 ◽  
Author(s):  
P Debishree Subudhi ◽  
Sheetalnath Rooge ◽  
Swati Thangriyal ◽  
Reshu Aggarwal ◽  
Ekta Gupta ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Viral Load ◽  
Liver Disease ◽  
Chronic Liver Disease ◽  
Extracellular Vesicles ◽  
Nasal Swab ◽  
High Viral Load ◽  
Chronic Liver ◽  
Rt Pcr ◽  
Route Of Transmission

Background: There is a prolonged RT PCR positivity seen in COVID-19 infected patients up to 2 to 3 months. It is assumed that this virus is usually non-infective but there are hardly any study on the reactivation of this virus within the respiratory tract. We aim to investigate the presence of viral particles inside Extracellular vesicles (EV) and its role in underlying liver disease patients. Methods: SARS CoV2 nasal and throat swab RT-PCR positive n=78 {n=24(66.6%) chronic liver disease (CLD); n=52 (81.3%) non liver disease} n=5 RT PCR negative subjects (HC) were studied. SARS CoV2 patients were also followed up for day (d) 7, 14 and 28. Nasal swab [collected in viral transport media (VTM)] and plasma samples were investigated at each time point. Extracellular vesicles were isolated using differential ultracentrifugation. SARS CoV2 RNA was measured using qRT-PCR by Altona Real Star kit. Cellular origin of EV was confirmed using epithelial cells (Epcam+ CK19+ CDh1+), endothelial cells (CD31+CD45-), and hepatocytes (ASGPR+) surface markers by Flow cytometry. Results: The COVID19 patients {Mean age 54±23 years; 41 males} were having severity between moderate to severe. In patients with cirrhosis, the most common aetiology of liver disease was alcohol (MELD 22±8). In baseline RT-PCR positive patients, SARS-CoV2 RNA inside the EV was present in 64/74 (82%) patients with comparable viral load between VTM and EV (mean 1/CT 0.033±0.005 vs. 1/CT 0.029±0.014, p=ns). On follow-up at day 7, of the 24 patients negative for COVID19, 10 (41%) had persistence of virus in the EV (1/CT 0.028±0.004) and on day 14, 14 of 40 (35%) negative RT-PCR had EVs with SARS CoV2 RNA (1/CT 0.028±0.06). The mean viral load decreased at day7 and day14 in nasal swab from baseline (p=0.001) but not in EV. SARS-CoV2 RNA otherwise undetectable in plasma, was found to be positive in EV in 12.5% of COVID19 positive patients. Interestingly, significantly prolonged and high viral load was found in EV at day 14 in CLD COVID19 patients compared to COVID19 alone (p=0.002). The high cellular injury was seen in CLD COVID19 infected patients with significant high levels of EV associated with endothelial cells and hepatocytes than COVID19 alone (p=0.004; 0.001). Conclusion: Identification of SARS-CoV2 RNA in EV, in RT-PCR negative patients indicates persistence of infection for and likely recurrence of the infection. It is suggestive of another route of transmission as EV harbour SARS CoV2 RNA. EV associated RNA may determine the ongoing inflammation and clinical course of subjects with undetectable SARS-CoV2 virus and this may also have relevance in management of chronic liver disease patients.

scholarly journals Rapid Diagnosis of SARS-CoV-2 Pneumonia on Lower Respiratory Tract Specimens

2021 ◽  
Author(s):  
Vanessa De Pace ◽  
Patrizia Caligiuri ◽  
Valentina Ricucci ◽  
Nicola Nigro ◽  
Barbara Galano ◽  
...  
Keyword(s):  
Intensive Care ◽  
Viral Load ◽  
Respiratory Tract ◽  
Intensive Care Units ◽  
Lower Respiratory Tract ◽  
Clinical Decision Making ◽  
High Viral Load ◽  
Rt Pcr ◽  
Predictive Values ◽  
Rapid Pcr

Abstract Background: The ongoing pandemic of SARS-CoV-2 requires the availability of accurate and rapid diagnostic tests, especially in some clinical settings like emergency and intensive care units. The objective of this study was to evaluate the diagnostic performances of rapid PCR kit Vivalytic SARS-CoV-2 in lower respiratory tract (LRT) specimens.Methods: A consecutive sample of LRT specimens (bronchoalveolar lavage and bronchoaspirates) was collected from Intensive Care Units of San Martino Hospital (Genoa, Italy) between November 2020 and January 2021. All samples were tested in RT-PCR by using Allplex™ SARS-CoV-2 assay (Seegene Inc., South Korea). Based on RT-PCR results, specimens were categorized into negative, positive with high viral load [cycle threshold (Ct) ≤30] and positive with low viral load (Ct of 31–35). A quota 1:1:1 sampling was used to achieve a sample size of 75. Then, all specimens were tested in the rapid PCR assay Vivalytic SARS-CoV-2 (Bosch Healthcare Solutions GmbH, Germany). The diagnostic performance of the rapid PCR against RT-PCR was assessed through calculation of accuracy, Cohen’s κ, sensitivity, specificity and expected positive (PPV) and negative (NPV) predictive values.Results: The overall diagnostic accuracy of the Vivalytic SARS-CoV-2 was 97.3% (95% CI: 90.9–99.3%) with an excellent Cohen’s κ of 0.94 (95% CI: 0.72–1). The sensitivity and specificity were 96% (95% CI: 86.5–98.9%) and 100% (95% CI: 86.7–100%), respectively. Samples with high viral loads had a sensitivity of 100% (Table 1). The distributions of E gene Ct values were similar (Wilcoxon’s test: P=0.070) with medians of 35 (IQR: 25–36) and 35 (IQR: 25–35), respectively (Figure 1). NPV and PPV was 92.6% and 100%, respectively.Conclusions: This study shows Vivalytic SARS-CoV-2 can be used following the sample liquefaction on LRT specimens. It’s a feasible and highly accurate molecular procedure especially in high viral load samples. This assay allows having a result in about 40 min and therefore may accelerate the clinical decision making in urgent/emergency situations.

scholarly journals A prospective clinical pilot study on the effects of a hydrogen peroxide mouthrinse on the intraoral viral load of SARS-CoV-2

2020 ◽  
Vol 24 (10) ◽  
pp. 3707-3713
Author(s):  
Maximilian J. Gottsauner ◽  
Ioannis Michaelides ◽  
Barbara Schmidt ◽  
Konstantin J. Scholz ◽  
Wolfgang Buchalla ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Clinical Trials ◽  
Viral Load ◽  
Pilot Study ◽  
High Risk ◽  
Infection Prevention ◽  
Healthcare Professionals ◽  
Patient Contact ◽  
Rt Pcr ◽  
Virus Culture

Abstract Objectives SARS-CoV-2 is mainly transmitted by inhalation of droplets and aerosols. This puts healthcare professionals from specialties with close patient contact at high risk of nosocomial infections with SARS-CoV-2. In this context, preprocedural mouthrinses with hydrogen peroxide have been recommended before conducting intraoral procedures. Therefore, the aim of this study was to investigate the effects of a 1% hydrogen peroxide mouthrinse on reducing the intraoral SARS-CoV-2 load. Methods Twelve out of 98 initially screened hospitalized SARS-CoV-2-positive patients were included in this study. Intraoral viral load was determined by RT-PCR at baseline, whereupon patients had to gargle mouth and throat with 20 mL of 1% hydrogen peroxide for 30 s. After 30 min, a second examination of intraoral viral load was performed by RT-PCR. Furthermore, virus culture was performed for specimens exhibiting viral load of at least 103 RNA copies/mL at baseline. Results Ten out of the 12 initially included SARS-CoV-2-positive patients completed the study. The hydrogen peroxide mouthrinse led to no significant reduction of intraoral viral load. Replicating virus could only be determined from one baseline specimen. Conclusion A 1% hydrogen peroxide mouthrinse does not reduce the intraoral viral load in SARS-CoV-2-positive subjects. However, virus culture did not yield any indication on the effects of the mouthrinse on the infectivity of the detected RNA copies. Clinical relevance The recommendation of a preprocedural mouthrinse with hydrogen peroxide before intraoral procedures is questionable and thus should not be supported any longer, but strict infection prevention regimens are of paramount importance. Trial registration German Clinical Trials Register (ref. DRKS00022484)

scholarly journals SARS-CoV-2 detection using digital PCR for COVID-19 diagnosis, treatment monitoring and criteria for discharge

2020 ◽  
Author(s):  
Renfei Lu ◽  
Jian Wang ◽  
Min Li ◽  
Yaqi Wang ◽  
Jia Dong ◽  
...  
Keyword(s):  
Viral Load ◽  
Limit Of Detection ◽  
False Negative ◽  
Digital Pcr ◽  
Detection Sensitivity ◽  
Rt Pcr ◽  
Pharyngeal Swab ◽  
Clinical Specimens ◽  
Positive Results ◽  
Negative Detection

SummaryBackgroundSARS-CoV-2 nucleic acid detection by RT-PCR is one of the criteria approved by China FDA for diagnosis of COVID-19. However, inaccurate test results (for example, high false negative rate and some false positive rate) were reported in both China and US CDC using RT-PCR method. Inaccurate results are caused by inadequate detection sensitivity of RT-PCR, low viral load in some patients, difficulty to collect samples from COVID-19 patients, insufficient sample loading during RT-PCR tests, and RNA degradation during sample handling process. False negative detection could subject patients to multiple tests before diagnosis can be made, which burdens health care system. Delayed diagnosis could cause infected patients to miss the best treatment time window. False negative detection could also lead to prematurely releasing infected patients who still carry residual SARS-CoV-2 virus. In this case, these patients could infect many others. A high sensitivity RNA detection method to resolve the existing issues of RT-PCR is in need for more accurate COVID-19 diagnosis.MethodsDigital PCR (dPCR) instrument DropX-2000 and assay kits were used to detect SARS-CoV-2 from 108 clinical specimens from 36 patients including pharyngeal swab, stool and blood from different days during hospitalization. Double-blinded experiment data of 108 clinical specimens by dPCR methods were compared with results from officially approved RT-PCR assay. A total of 109 samples including 108 clinical specimens and 1 negative control sample were tested in this study. All of 109 samples, 26 were from 21patients reported as positive by officially approved clinical RT-PCR detection in local CDC and then hospitalized in Nantong Third Hospital. Among the 109 samples, dPCR detected 30 positive samples on ORFA1ab gene, 47 samples with N gene positive, and 30 samples with double positive on ORFA1ab and N genes.ResultsThe lower limit of detection of the optimize dPCR is at least 10-fold lower than that of RT-PCR. The overall accuracy of dPCR for clinical detection is 96.3%. 4 out 4 of (100 %) negative pharyngeal swab samples checked by RT-PCR were positive judged by dPCR based on the follow-up investigation. 2 of 2 samples in the RT-PCR grey area (Ct value > 37) were confirmed by dPCR with positive results. 1 patient being tested positive by RT-PCR was confirmed to be negative by dPCR. The dPCR results show clear viral loading decrease in 12 patients as treatment proceed, which can be a useful tool for monitoring COVID-19 treatment.ConclusionsDigital PCR shows improved lower limit of detection, sensitivity and accuracy, enabling COVID-19 detection with less false negative and false positive results comparing with RT-PCR, especially for the tests with low viral load specimens. We showed evidences that dPCR is powerful in detecting asymptomatic patients and suspected patients. Digital PCR is capable of checking the negative results caused by insufficient sample loading by quantifying internal reference gene from human RNA in the PCR reactions. Multi-channel fluorescence dPCR system (FAM/HEX/CY5/ROX) is able to detect more target genes in a single multiplex assay, providing quantitative count of viral load in specimens, which is a powerful tool for monitoring COVID-19 treatment.

scholarly journals Direct Quantitation of SARS-CoV-2 Using Droplet Digital PCR in Suspected Samples With Very Low Viral Load

2021 ◽  
Author(s):  
Michela Deiana ◽  
Chiara Piubelli ◽  
Antonio Mori ◽  
Gian Paolo Chiecchi ◽  
Giulia La Marca ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
False Negative ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Hospitalized Patients ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Viral Genes ◽  
Viral Target

Background: The reference test for SARS-CoV-2 detection is the reverse transcriptase real time PCR (real time RT-PCR). However, evidences reported that real time RT-PCR has a lower sensitivity compared with the droplet digital PCR (ddPCR) leading to possible false negative in low viral load cases. Methods: We used ddPCR for viral genes N1 and N2 on 20 negative (no detection) samples from symptomatic hospitalized COVID-patients presenting fluctuating real time RT-PCR results and 10 suspected samples (Ct value&gt;35) from asymptomatic not hospitalized subjects. Results: ddPCR performed on RNA revealed 65% of positivity for at least one viral target in the hospitalized patients group of samples (35% for N1 and N2, 10% only for N1 and 20% only for N2) and 50% in the suspected cases (30% for N1 and N2, while 20% only for N2). On hospitalized patients&rsquo; samples, we applied also a direct ddPCR approach on the swab material, achieving an overall positivity of 83%. Conclusion: ddPCR, in particular the direct quantitation on swabs, shows a sensitivity advantage for the SARS-CoV-2 identification and may be useful to reduce the false negative diagnosis, especially for low viral load suspected samples.

scholarly journals Viral load and antibody levels in patients with COVID-19

2021 ◽  
Vol 8 (3) ◽  
pp. 010-018
Author(s):  
Iva Christova ◽  
Iva Trifonova ◽  
Teodora Gladnishka ◽  
Elena Dragusheva ◽  
Georgi Popov ◽  
...  
Keyword(s):  
Viral Load ◽  
High Viral Load ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Serum Samples ◽  
Weekly Basis ◽  
Specific Antibody Response ◽  
Viral Loads ◽  
Antibody Levels ◽  
Kinetics Of

Relations between viral load, antibody levels and COVID-19 severity are not well studied and results from such investigations are controversial. In this study, we investigated kinetics of viral load and antibody responses to SARS-CoV-2 in 20 patients with COVID-19 and analysed the association with disease severity. The patients were followed on weekly basis within the first month after the onset and then once per month for the next 4 months. Serum samples were tested for IgA, IgM, and IgG antibodies against SARS-CoV-2 using ELISA tests. SARS-CoV-2 viral load in nasopharyngeal swabs was measured by quantitative Realtime RT-PCR. For vast majority of the patients, the viral loads were at their highest levels at presentation and then declined gradually. Despite development of specific antibody response 7-11 days after the onset of COVID-19, SARS-CoV-2 RNA was still detected in nasopharyngeal swabs of most of the patients. There was no direct link between viral load and severity of COVID-19: some of mild and some of severe cases started with a high viral load. There was a relationship between the time from the onset of the disease and the viral load: the highest viral load was in the first days. In more severe cases, there was a tendency for slower reduction in viral load and longer detection of SARS-CoV-2 virus. Levels of the specific antibodies increased earlier and to higher levels and were present for longer time in patients with more severe manifestations of COVID-19 than in those with milder disease.

scholarly journals Saliva: Both a Threat and an Opportunity in Covid-19 Pandemic

2021 ◽  
Vol 37 (4) ◽  
Author(s):  
Ismail Serhat Sadıkoğlu ◽  
Mehmet Gagari Caymaz
Keyword(s):  
Viral Load ◽  
Diagnostic Technique ◽  
High Viral Load ◽  
Rt Pcr ◽  
Creative Commons ◽  
Aerosol Exposure ◽  
Cochrane Database ◽  
Dental Practitioners ◽  
Day By Day ◽  
Open Access Article

Covid-19 pandemic, continues all over the world with the increasing number of confirmed cases and performed tests day by day. It has been shown that collecting nasopharyngeal samples, as the most commonly prefered method to perform RT-PCR, has disadvantages like causing discomfort and bleeding in patients. Sample collecting procedure also renders healthcare professionals by exposing them to the risk of transmission of the virus related to the direct contact with patients. These disadvantages make this procedure undesirable for the researchers and forces them to search for an alternative technique. At this point, saliva appears as an opportunity, regarding its high viral load. On the other hand, this high viral load poses a threat, especially for professions such as dental practitioners, with too much aerosol exposure. Since dentistry is a branch of health that constantly needs direct operations, it is necessary to be protected from the virus as much as possible while caring for the patient. A literature review was done using electronic databases “PubMed,” “Google Scholar,” and “Cochrane Database,” on January 2021. Studies have proposed many different preventive measures in this regard. Therefore, the purpose of this review is to draw attention to the saliva by bringing together the recent research and also to provide information and a perspective to dental clinicians about both prevention and a potential diagnostic technique. doi: https://doi.org/10.12669/pjms.37.4.4263 How to cite this:Sadikoglu IS, Caymaz MG. Saliva: Both a Threat and an Opportunity in Covid-19 Pandemic. Pak J Med Sci. 2021;37(4):---------.  doi: https://doi.org/10.12669/pjms.37.4.4263 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

scholarly journals Performance characteristics of a rapid SARS-CoV-2 antigen detection assay at a public plaza testing site in San Francisco

2020 ◽  
Author(s):  
Genay Pilarowski ◽  
Paul Lebel ◽  
Sara Sunshine ◽  
Jamin Liu ◽  
Emily Crawford ◽  
...  
Keyword(s):  
Viral Load ◽  
San Francisco ◽  
High Viral Load ◽  
Performance Characteristics ◽  
Viral Rna ◽  
Antigen Test ◽  
Rt Pcr ◽  
Detection Assay ◽  
Community Transmission ◽  
Testing Site

ABSTRACTWe evaluated the performance of the Abbott BinaxNOW™ Covid-19 rapid antigen test to detect virus among persons, regardless of symptoms, at a public plaza site of ongoing community transmission. Titration with cultured clinical SARS-CoV-2 yielded a human observable threshold between 1.6×104-4.3×104 viral RNA copies (cycle threshold (Ct) of 30.3-28.8 in this assay). Among 878 subjects tested, 3% (26/878) were positive by RT-PCR, of which 15/26 had a Ct<30, indicating high viral load. 40% (6/15) of Ct<30 were asymptomatic. Using this Ct<30 threshold for Binax-CoV2 evaluation, the sensitivity of the Binax-CoV2 was 93.3% (14/15), 95% CI: 68.1-99.8%, and the specificity was 99.9% (855/856), 95% CI: 99.4-99.9%.

scholarly journals Viral load of SARS-CoV-2 in adults during the first and second wave of COVID-19 pandemic in Houston, TX: the potential of the super-spreader

2021 ◽  
Author(s):  
Vasanthi Avadhanula ◽  
Erin G Nicholson ◽  
Laura Ferlic-Stark ◽  
Felipe-Andres Piedra ◽  
Brittani N Blunck ◽  
...  
Keyword(s):  
Viral Load ◽  
Contingency Table ◽  
Social Dynamics ◽  
High Viral Load ◽  
Rt Pcr ◽  
Median Viral Load ◽  
Viral Shedding ◽  
The Social ◽  
Second Wave ◽  
Index Cases

Abstract Background During the COVID-19 pandemic, a minority of index cases are associated with a majority of secondary cases suggesting that super-spreaders could drive the pandemic. We identified a phenotype in individuals with extremely high viral load who could act as super-spreaders. Methods Data were analyzed from individuals tested for SARS-CoV-2 from March 18 through August 15, 2020. Outcomes were compared using contingency table and quantile regression to test the equality of medians between the pandemic waves and by viral load groups. Results Of the 11,564 samples tested, 1,319 (11.4%) were positive for SARS-CoV-2. An increase in weekly median viral load occurred in the second wave of the SARS-CoV2 pandemic. This population was more likely to be women, outpatients, symptomatic and have an extremely high or high viral load. In patients with multiple RT-PCR positive tests, the duration of viral shedding was comparable between individuals with asymptomatic/mild and mild/moderate illness severity. Conclusions We detected a small group of individuals with extremely high SARS-CoV-2 viral load with mild illness. We believe that these individuals’ characteristics could be consistent with the super-spreader phenomenon and that greater awareness of the social dynamics of these individuals is needed to understand the spread of SARS-CoV-2.

scholarly journals Smartphone Screen Testing, a novel pre-diagnostic method to identify SARS-CoV-2 infectious individuals

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Rodrigo M Young ◽  
Camila J Solis-Cascante ◽  
Andres Barriga-Fehrman ◽  
Carlos Abogabir ◽  
Alvaro R Thadani ◽  
...  
Keyword(s):  
Viral Load ◽  
Diagnostic Method ◽  
Cost Effective ◽  
High Viral Load ◽  
Rt Pcr ◽  
Non Invasive ◽  
Alpha Beta ◽  
To Come

The COVID-19 pandemic will likely take years to control globally, and constant epidemic surveillance will be required to limit the spread of SARS-CoV-2, especially considering the emergence of new variants that could hamper the effect of vaccination efforts. We developed a simple and robust - Phone Screen Testing (PoST) - method to detect positive SARS-CoV-2 individuals by RT-PCR testing of smartphone screen swab samples. We show that 81.3-100% of individuals with high-viral load SARS-CoV-2 nasopharyngeal positive samples also test positive for PoST, suggesting this method is effective in identifying COVID-19 contagious individuals. Furthermore, we successfully identified polymorphisms associated with SARS-CoV-2 Alpha, Beta and Gamma variants, in SARS-CoV-2 positive PoST samples. Overall, we report that PoST is a new non-invasive, cost-effective, and easy to implement smartphone-based smart alternative for SARS-CoV-2 testing, which could help to contain COVID-19 outbreaks and identification of variants of concern in the years to come.

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