SARS-CoV-2 RNA detected in blood products from patients with COVID-19 is not associated with infectious virus

Background: Laboratory diagnosis of SARS-CoV-2 infection (the cause of COVID-19) uses PCR to detect viral RNA (vRNA) in respiratory samples. SARS-CoV-2 RNA has also been detected in other sample types, but there is limited understanding of the clinical or laboratory significance of its detection in blood. Methods: We undertook a systematic literature review to assimilate the evidence for the frequency of vRNA in blood, and to identify associated clinical characteristics. We performed RT-PCR in serum samples from a UK clinical cohort of acute and convalescent COVID-19 cases (n=212), together with convalescent plasma samples collected by NHS Blood and Transplant (NHSBT) (n=462 additional samples). To determine whether PCR-positive blood samples could pose an infection risk, we attempted virus isolation from a subset of RNA-positive samples. Results: We identified 28 relevant studies, reporting SARS-CoV-2 RNA in 0-76% of blood samples; pooled estimate 10% (95%CI 5-18%). Among serum samples from our clinical cohort, 27/212 (12.7%) had SARS-CoV-2 RNA detected by RT-PCR. RNA detection occurred in samples up to day 20 post symptom onset, and was associated with more severe disease (multivariable odds ratio 7.5). Across all samples collected ≥28 days post symptom onset, 0/494 (0%, 95%CI 0-0.7%) had vRNA detected. Among our PCR-positive samples, cycle threshold (ct) values were high (range 33.5-44.8), suggesting low vRNA copy numbers. PCR-positive sera inoculated into cell culture did not produce any cytopathic effect or yield an increase in detectable SARS-CoV-2 RNA. Conclusions: vRNA was detectable at low viral loads in a minority of serum samples collected in acute infection, but was not associated with infectious SARS-CoV-2 (within the limitations of the assays used). This work helps to inform biosafety precautions for handling blood products from patients with current or previous COVID-19.

Download Full-text

SARS-CoV-2 RNA detected in blood products from patients with COVID-19 is not associated with infectious virus

Wellcome Open Research ◽

10.12688/wellcomeopenres.16002.2 ◽

2020 ◽

Vol 5 ◽

pp. 181

Author(s):

Monique I. Andersson ◽

Carolina V. Arancibia-Carcamo ◽

Kathryn Auckland ◽

J. Kenneth Baillie ◽

Eleanor Barnes ◽

...

Keyword(s):

Symptom Onset ◽

Severe Disease ◽

Acute Infection ◽

Laboratory Diagnosis ◽

Blood Products ◽

Rt Pcr ◽

Serum Samples ◽

Blood Samples ◽

Viral Loads ◽

Clinical Cohort

Background: Laboratory diagnosis of SARS-CoV-2 infection (the cause of COVID-19) uses PCR to detect viral RNA (vRNA) in respiratory samples. SARS-CoV-2 RNA has also been detected in other sample types, but there is limited understanding of the clinical or laboratory significance of its detection in blood. Methods: We undertook a systematic literature review to assimilate the evidence for the frequency of vRNA in blood, and to identify associated clinical characteristics. We performed RT-PCR in serum samples from a UK clinical cohort of acute and convalescent COVID-19 cases (n=212), together with convalescent plasma samples collected by NHS Blood and Transplant (NHSBT) (n=462 additional samples). To determine whether PCR-positive blood samples could pose an infection risk, we attempted virus isolation from a subset of RNA-positive samples. Results: We identified 28 relevant studies, reporting SARS-CoV-2 RNA in 0-76% of blood samples; pooled estimate 10% (95%CI 5-18%). Among serum samples from our clinical cohort, 27/212 (12.7%) had SARS-CoV-2 RNA detected by RT-PCR. RNA detection occurred in samples up to day 20 post symptom onset, and was associated with more severe disease (multivariable odds ratio 7.5). Across all samples collected ≥28 days post symptom onset, 0/494 (0%, 95%CI 0-0.7%) had vRNA detected. Among our PCR-positive samples, cycle threshold (ct) values were high (range 33.5-44.8), suggesting low vRNA copy numbers. PCR-positive sera inoculated into cell culture did not produce any cytopathic effect or yield an increase in detectable SARS-CoV-2 RNA. There was a relationship between RT-PCR negativity and the presence of total SARS-CoV-2 antibody (p=0.02). Conclusions: vRNA was detectable at low viral loads in a minority of serum samples collected in acute infection, but was not associated with infectious SARS-CoV-2 (within the limitations of the assays used). This work helps to inform biosafety precautions for handling blood products from patients with current or previous COVID-19.

Download Full-text

SARS-CoV-2 RNA detected in blood samples from patients with COVID-19 is not associated with infectious virus

10.1101/2020.05.21.20105486 ◽

2020 ◽

Cited By ~ 5

Author(s):

Monique I Andersson ◽

Carolina V Arancibia-Cárcamo ◽

Kathryn Auckland ◽

J Kenneth Baillie ◽

Eleanor Barnes ◽

...

Keyword(s):

Symptom Onset ◽

Severe Disease ◽

Acute Infection ◽

Laboratory Diagnosis ◽

Rt Pcr ◽

Serum Samples ◽

Blood Samples ◽

Viral Loads ◽

Clinical Cohort ◽

Copy Numbers

ABSTRACTBackgroundLaboratory diagnosis of SARS-CoV-2 infection (the cause of COVID-19) uses PCR to detect viral RNA (vRNA) in respiratory samples. SARS-CoV-2 RNA has also been detected in other sample types, but there is limited understanding of the clinical or laboratory significance of its detection in blood.MethodsWe undertook a systematic literature review to assimilate the evidence for the frequency of vRNA in blood, and to identify associated clinical characteristics. We performed RT-PCR in serum samples from a UK clinical cohort of acute and convalescent COVID-19 cases (n=212), together with convalescent plasma samples collected by NHS Blood and Transplant (NHSBT) (n=111 additional samples). To determine whether PCR-positive blood samples could pose an infection risk, we attempted virus isolation from a subset of RNA-positive samples.ResultsWe identified 28 relevant studies, reporting SARS-CoV-2 RNA in 0-76% of blood samples; pooled estimate 10% (95%CI 5-18%). Among serum samples from our clinical cohort, 27/212 (12.7%) had SARS-CoV-2 RNA detected by RT-PCR. RNA detection occurred in samples up to day 20 post symptom onset, and was associated with more severe disease (multivariable odds ratio 7.5). Across all samples collected ≥28 days post symptom onset, 0/143 (0%, 95%CI 0.0-2.5%) had vRNA detected. Among our PCR-positive samples, cycle threshold (ct) values were high (range 33.5-44.8), suggesting low vRNA copy numbers. PCR-positive sera inoculated into cell culture did not produce any cytopathic effect or yield an increase in detectable SARS-CoV-2 RNA.ConclusionsvRNA was detectable at low viral loads in a minority of serum samples collected in acute infection, but was not associated with infectious SARS-CoV-2 (within the limitations of the assays used). This work helps to inform biosafety precautions for handling blood products from patients with current or previous COVID-19.

Download Full-text

SAT0253 ANTI-NEUTROPHIL CYTOPLASMATIC ANTIBODIES PREDATE SYMPTOM ONSET OF ANCA-ASSOCIATED VASCULITIS. A CASE-CONTROL STUDY

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.2799 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1069.2-1070

Author(s):

E. Berglin ◽

A. J. Mohammad ◽

J. Dahlqvist ◽

C. Eriksson ◽

J. Sjöwall ◽

...

Keyword(s):

Cause Of Death ◽

Symptom Onset ◽

Severe Disease ◽

Disease Onset ◽

Control Sample ◽

Discharge Summary ◽

Serum Samples ◽

Blood Samples ◽

Anca Associated Vasculitis ◽

Time Point

Background:Presence of anti-neutrophil cytoplasmatic autoantibodies (ANCA) is important for the diagnosis of ANCA-associated vasculitis (AAV) and reflects on-going immune processes. The timing of the antibody development and its contribution to disease is not well established.Objectives:To investigate the presence of proteinase 3 (PR3)- and myeloperoxidase (MPO)-ANCA in blood samples collected from healthy individuals who subsequently developed AAV.Methods:The Swedish National Patient Register of inpatient care and the Swedish Cause of Death Register were used to identify individuals assigned ICD codes for AAV (1) in the discharge summary or cause of death, respectively. The resulted cohort was then linked to the registers of 4 different biobanks to identify those with available predating blood samples. Diagnoses of AAV were confirmed and time point for onset of symptoms was identified by reviewing all available case records (1); 68 were classified as granulomatosis with polyangiitis (GPA), 14 as microscopic polyangiitis (MPA), and 4 as eosinophilic GPA (EGPA). The 86 cases (36 males, 50 females) had a mean (SD) age of 51.9 (16.9) years at sampling, with ≥1 sample (26% plasma, 74% serum samples). The sampling time point before onset of symptoms was mean (SD); 4.4 (3.1) years. Serum and plasma control samples (n=198; 82 males, 116 females; mean age (SD); 52.0 (16.5) years) were identified and matched for sex, age and date of sampling. The samples were first screened for ANCA using high sensitive ELISA (ORGANTEC diagnostika, Germany) and samples close to or above cut-off level were further analysed for capture PR3- and capture MPO-ANCA (ELISA; SVAR Life Science, Sweden). For each case one control sample was included for the ANCA specificity tests. Statistical calculations were performed using SPSS software.Results:In ANCA-screen 36.0% of the cases and 2.6 % of controls tested positive (p<0.001). 23/52 (44.2%) of the cases were PR3-ANCA positive (OR 56.3; 95% CI 7.26-436.62) and 8/52 (15.4%) were MPO-ANCA positive (OR 4.18; 95% CI 1.05-16.62). The mean (SD) predating time for PR3-ANCA positivity was 3.73 (3.49) years and for MPO-ANCA positivity 2.11 (1.46) years. Cases with positive predating PR3-ANCA were younger (46.0±19.4 vs 65.6±12.0 years; P<0.001) than cases with a negative predating PR3-ANCA. MPO-ANCA positive vs. MPO-ANCA negative pre-dating cases had more often severe disease (kidney/lung/peripheral nervous system) (OR 15.08; 95% CI 1.68—135.54) at disease onset. Furthermore, predating MPO-ANCA positive vs predating PR3-ANCA positive cases had significantly more often severe manifestations at disease onset (87.5% vs 28.6%; p<0.05). Cases positive vs. negative for MPO-ANCA in predating samples were less often classified as GPA (37.5% vs 86.4%; p<0.01) and more often as MPA (62.5% vs 13.6%; p<0.05).Conclusion:The production of both PR3 and MPO-ANCA starts already years before onset of symptoms of AAV. Presence of MPO-ANCA appeared closer to symptom onset and with more severe disease presentation. Differences in the disease phenotype and disease severity were evident between the two ANCA serotypes.References:[1]Watts et al. Ann Rheum Dis 2007;66:222-22Acknowledgments: :Vasculitis Foundation, USADisclosure of Interests:Ewa Berglin: None declared, Aladdin J Mohammad Speakers bureau: lecture fees from Roche and Elli Lilly Sweden, PI (GiACTA study), Johanna Dahlqvist: None declared, Catharina Eriksson: None declared, Johanna Sjöwall: None declared, Solbritt Rantapää Dahlqvist: None declared

Download Full-text

Analytical and diagnostic performances of a high-throughput immunoassay for SARS-CoV-2 IgM and IgG

10.1101/2020.11.20.20235267 ◽

2020 ◽

Author(s):

Andrea Padoan ◽

Chiara Cosma ◽

Paolo Zaupa ◽

Mario Plebani

Keyword(s):

Sensitivity And Specificity ◽

Symptom Onset ◽

Severe Disease ◽

Onset Time ◽

Time Frame ◽

Serum Samples ◽

Time Period ◽

Analytical Imprecision ◽

Range Of Values

BackgroundAbstractReliable SARS-CoV-2 serological assays are required for diagnosing infections, for the serosurveillance of past exposures and for assessing the response to future vaccines. In this study, the analytical and clinical performances of a chemiluminescent immunoassays for SARS-CoV-2 IgM and IgG detection (Mindray CL-1200i), targeting Nucleocapsid (N) and receptor binding domain (RBD) portion of the Spike protein, were evaluated.MethodsPrecision and linearity were evaluated using standardized procedures. A total of 157 leftover serum samples from 81 hospitalized confirmed COVID-19 patients (38 with moderate and 43 with severe disease) and 76 SARS-CoV-2 negative subjects (44 healthcare workers, 20 individuals with rheumatic disorders, 12 pregnant women) were included in the study. In an additional series of 44 SARS-CoV-2 positive, IgM and IgG time kinetics were also evaluated in a time-period of 38 days.ResultsPrecision was below or equal to 4% for both IgM and IgG, in all the studied levels, whilst a slightly significant deviation from linearity was observed for both assays in the range of values covering the manufacturer’s cut-off. Considering a time frame ≥ 12 days post symptom onset, sensitivity and specificity for IgM were 92.3% (95%CI:79.1%-98.4%) and 92.1% (95%CI:83.6%-97.0%). In the same time frame, sensitivity and specificity for IgG were 100% (95%CI:91.0%-100%) and 93.4% (95%CI:85.3%-97.8%). The assays agreement was 73.9% (Cohen’s kappa of 0.373). Time kinetics showed a substantial overlapping of IgM and IgG response, the latter values being elevated up to 38 days from symptoms onset.ConclusionsAnalytical imprecision is satisfactory as well as the linearity, particularly when taking into account the fact that both assays are claimed to be qualitative. Diagnostic sensitivity of IgG was excellent, especially considering specimens collected ≥12 days post symptom onset. Time kinetics suggest that IgM and IgG are detectable early in the course of infection, but the role of SARS-CoV-2 antibodies in clinical practice still requires further evaluations.

Download Full-text

Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, January-March 2020: retrospective cohort study

BMJ ◽

10.1136/bmj.m1443 ◽

2020 ◽

pp. m1443 ◽

Cited By ~ 319

Author(s):

Shufa Zheng ◽

Jian Fan ◽

Fei Yu ◽

Baihuan Feng ◽

Bin Lou ◽

...

Keyword(s):

Viral Load ◽

Retrospective Cohort ◽

Severe Disease ◽

Zhejiang Province ◽

Serum Samples ◽

Viral Loads ◽

Mild Disease ◽

Stool Samples ◽

Serum And Urine ◽

Serum And Urine Samples

AbstractObjectiveTo evaluate viral loads at different stages of disease progression in patients infected with the 2019 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the first four months of the epidemic in Zhejiang province, China.DesignRetrospective cohort study.SettingA designated hospital for patients with covid-19 in Zhejiang province, China.Participants96 consecutively admitted patients with laboratory confirmed SARS-CoV-2 infection: 22 with mild disease and 74 with severe disease. Data were collected from 19 January 2020 to 20 March 2020.Main outcome measuresRibonucleic acid (RNA) viral load measured in respiratory, stool, serum, and urine samples. Cycle threshold values, a measure of nucleic acid concentration, were plotted onto the standard curve constructed on the basis of the standard product. Epidemiological, clinical, and laboratory characteristics and treatment and outcomes data were obtained through data collection forms from electronic medical records, and the relation between clinical data and disease severity was analysed.Results3497 respiratory, stool, serum, and urine samples were collected from patients after admission and evaluated for SARS-CoV-2 RNA viral load. Infection was confirmed in all patients by testing sputum and saliva samples. RNA was detected in the stool of 55 (59%) patients and in the serum of 39 (41%) patients. The urine sample from one patient was positive for SARS-CoV-2. The median duration of virus in stool (22 days, interquartile range 17-31 days) was significantly longer than in respiratory (18 days, 13-29 days; P=0.02) and serum samples (16 days, 11-21 days; P<0.001). The median duration of virus in the respiratory samples of patients with severe disease (21 days, 14-30 days) was significantly longer than in patients with mild disease (14 days, 10-21 days; P=0.04). In the mild group, the viral loads peaked in respiratory samples in the second week from disease onset, whereas viral load continued to be high during the third week in the severe group. Virus duration was longer in patients older than 60 years and in male patients.ConclusionThe duration of SARS-CoV-2 is significantly longer in stool samples than in respiratory and serum samples, highlighting the need to strengthen the management of stool samples in the prevention and control of the epidemic, and the virus persists longer with higher load and peaks later in the respiratory tissue of patients with severe disease.

Download Full-text

Comparison of SARS-CoV-2 antigen electrochemiluminescence immunoassay to RT-PCR assay for laboratory diagnosis of COVID-19 in Peshawar

Diagnosis ◽

10.1515/dx-2021-0078 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Bilal Iqbal ◽

Maria Khan ◽

Noman Shah ◽

Mirza Muhammad Dawood ◽

Valeed Jehanzeb ◽

...

Keyword(s):

Laboratory Diagnosis ◽

Cross Sectional Study ◽

Antigen Test ◽

Rt Pcr ◽

Pcr Assay ◽

Cross Sectional ◽

Viral Loads ◽

Testing Algorithms ◽

Frequent Testing ◽

Antigen Testing

Abstract Objectives Antigen based rapid diagnostic tests possesses a potential to be utilized along with Gold standard methods to detect Covid-19 infection to cope with the demand of testing. The aim of this study was to determine diagnostic accuracy of electrochemiluminescence based automated antigen detection immunoassay comparing with molecular based test RT-PCR (Covid-19). Methods It was a cross-sectional study conducted in RMI Peshawar, from 1st April 2021 till 30th April 2021. The study comprised 170 individuals who were suspected of having Covid-19. Nasopharyngeal samples taken from suspected individuals were analyzed by RT-PCR and automated antigen test (Elecsys SARS-CoV-2 Antigen) simultaneously. The correlation of SARS-CoV-2 antigen with PCR positive and negative cases was analyzed for specificity, sensitivity respectively. Results The ECLIA based Elecsys antigen test (Roche) revealed overall sensitivity 72%, specificity 95% and accuracy of 94.9%. Sensitivity of antigen test progressively declined from 94.3% in Ct <25 to 70.8% in Ct 26–29 and then to 47.2% in Ct 30–35. Conclusions Based on the findings of our study we conclude that automated antigen testing (Elecsys SARS-CoV-2 Antigen) cannot replace molecular based testing like RT PCR. Elecsys SARS-CoV-2 Ag test should be used complementary to RT-PCR in testing algorithms. Frequent testing strategy should be adopted while using automated antigen testing to overcome its limitation in individuals with low viral loads.

Download Full-text

SARS-CoV-2 RNA and antibody dynamics in a Dutch household study with dense sampling frame

10.1101/2021.10.06.21263384 ◽

2021 ◽

Author(s):

Wanda G.H. Han ◽

Arno Swart ◽

Axel Bonacic Marinovic ◽

Dirk Eggink ◽

Johan Reimerink ◽

...

Keyword(s):

Symptom Onset ◽

Symptom Severity ◽

Oral Fluid ◽

Probability Of Detection ◽

Serological Response ◽

Sample Type ◽

Sampling Frame ◽

Rt Pcr ◽

Specific Antibodies ◽

Viral Loads

AbstractThis study investigated the dynamics of SARS-CoV-2 infection and diagnostics in household members of different ages and with different symptom severity after SARS-CoV-2 exposure during the early phase of the pandemic. Households with a SARS-CoV-2 confirmed positive case and at least one child in the Netherlands were followed for 6 weeks. Naso (NP)- and oropharyngeal (OP) swabs, oral fluid and feces specimens were analyzed for SARS-CoV-2 RNA and serum for SARS-CoV-2-specific antibodies. The dynamics of the presence of viral RNA and the serological response was modeled to determine the sampling time-frame and sample type with the highest sensitivity to confirm or reject a SARS-CoV-2 diagnosis. Transmission of SARS-CoV-2 between adults and children within a household was correlated with symptom severity of index cases. In children higher viral loads compared to adults were detected at symptom onset. Early in infection, higher viral loads were detected in NP and OP specimens, while RNA in especially feces were longer detectable. SARS-CoV-2-specific antibodies have a 90% probability of detection from 7 days (total Ig) and 18 days (IgG) since symptom onset. In conclusion this study has shown that on average, children carry higher loads of virus as compared to adults early after infection. For highest probability of detection in SARS-CoV-2 diagnostics early in infection, RT-PCR on NP and OP specimens are more sensitive than on oral fluid and feces. For SARS-CoV-2 diagnostics late after infection, RT-PCR on feces specimens and serology are more valuable.

Download Full-text

Clinical Evaluation of a COVID-19 Antibody Lateral Flow Assay using Point of Care Samples

10.1101/2020.12.02.20242750 ◽

2020 ◽

Author(s):

Won Lee ◽

Steven Straube ◽

Ryan Sincic ◽

Jeanne A. Noble ◽

Juan Carlos Montoy ◽

...

Keyword(s):

Predictive Value ◽

Point Of Care ◽

Acute Infection ◽

High Specificity ◽

Lateral Flow ◽

Lateral Flow Immunoassay ◽

Onset Date ◽

Rt Pcr ◽

Serum Samples ◽

Antibody Positivity

ABSTRACTIntroductionThe ongoing SARS-CoV-2 pandemic has spurred the development of numerous point of care (PoC) immunoassays. Assessments of performance of available kits are necessary to determine their clinical utility. Previous studies have mostly performed these assessments in a laboratory setting, which raises concerns of translating findings for PoC use. The aim of this study was to assess the performance of a lateral flow immunoassay for the detection of SARS-CoV-2 antibodies using samples collected at PoC.MethodOne lateral flow immunoassay (Humasis® COVID-19 IgG/IgM) was tested. In total, 50 PCR RT-PCR positive and 52 RT-PCR negative samples were collected at PoC. Fifty serum specimens from Dec 2018 to Feb 2019 were used as controls for specificity. Serum samples collected between Dec 2019 to Feb 2020 were used as additional comparators. Clinical data including symptom onset date was collected from patient history and the medical record.ResultsThe overall sensitivity for the kit was 74% (95% CI: 59.7% -85.4%). The sensitivity for IgM and IgG detection >14 days after date of onset was 88% (95% CI: 68.8% -97.5%) and 84% (95% CI: 63.9% – 95.5%), with a negative predictive value (NPV) of 94% for IgM (95% CI: 83.5% - 98.8%) and 93% for IgG (95% CI: 81.8% - 97.9%). The overall specificity was 94% (95% CI: 83.5% - 98.8%). The Immunoglobulin specific specificity was 94% for IgM (95% CI: 83.5% - 98.8%) and 98% for IgG (95% CI: 89.4% - 100.0%), with a positive predictive value (PPV) of 88% for IgM (95% CI: 68.8% - 97.5%) and 95% for IgG (95% CI: 77.2% - 99.9%) respectively for samples collected from patients >14 days after date of onset. Specimen collected during early phase of COVID-19 pandemic (Dec 2019 to Feb 2020) showed 11.8% antibody positivity, and 11.3% of PCR-negative patients demonstrated antibody positivity.DiscussionHumasis® COVID-19 IgG/IgM LFA demonstrates greater than 90% PPV and NPV for samples collected 14 days after the onset of symptoms using samples collected at PoC. While not practical for the diagnosis of acute infection, the use of the lateral flow assays with high specificity may have utility for determining seroprevalence or seroconversion in longitudinal studies.

Download Full-text

A novel RT-LAMP workflow for rapid salivary diagnostics of COVID-19 and effects of age, gender and time from symptom onset

10.1101/2021.06.07.21258288 ◽

2021 ◽

Author(s):

Gerson Shigeru Kobayashi ◽

Luciano Abreu Brito ◽

Danielle De Paula Moreira ◽

Angela May Suzuki ◽

Gabriella Shih Ping Hsia ◽

...

Keyword(s):

Viral Load ◽

Symptom Onset ◽

Clinical Performance ◽

Point Of Care ◽

Rapid Diagnostics ◽

Rt Pcr ◽

Point Of Care Testing ◽

Viral Loads ◽

Peak Viral Load ◽

Salivary Diagnostics

Objectives: Rapid diagnostics is pivotal to curb SARS-CoV-2 transmission, and saliva has emerged as a practical alternative to naso/oropharyngeal (NOP) specimens. We aimed to develop a direct RT-LAMP workflow for viral detection in saliva, and to provide more information regarding its potential in COVID-19 diagnostics. Methods: Clinical and contrived specimens were used to screen/optimize formulations and sample processing protocols. Salivary viral load was determined in symptomatic patients to evaluate clinical performance (n = 90) and to characterize saliva based on age, gender and time from onset of symptoms (n = 49). Results: The devised workflow achieved 93.2% sensitivity, 97% specificity, and 0.895 Kappa for salivas containing >102 copies/μL. Further analyses in saliva showed peak viral load in the first days of symptoms and lower viral loads in females, particularly among young individuals (<38 years). NOP RT-PCR data did not yield relevant associations. Conclusions: This novel saliva RT-LAMP workflow can be applied to point-of-care testing. This work reinforces that saliva better correlates with transmission dynamics than NOP specimens, and reveals gender differences that may reflect higher transmission by males. To maximize detection, testing should be done immediately after symptom onset, especially in females.

Download Full-text

Viral load and antibody levels in patients with COVID-19

GSC Advanced Research and Reviews ◽

10.30574/gscarr.2021.8.3.0180 ◽

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.

Download Full-text