Viral load and antibody levels in patients with COVID-19

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.

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Testing IgG antibodies against the RBD of SARS-CoV-2 is sufficient and necessary for COVID-19 diagnosis

PLoS ONE ◽

10.1371/journal.pone.0241164 ◽

2020 ◽

Vol 15 (11) ◽

pp. e0241164 ◽

Cited By ~ 1

Author(s):

Victoria Indenbaum ◽

Ravit Koren ◽

Shiri Katz-Likvornik ◽

Mayan Yitzchaki ◽

Osnat Halpern ◽

...

Keyword(s):

Igg Antibodies ◽

Serum Samples ◽

Igg Antibody ◽

Past Exposure ◽

Iga Antibodies ◽

Global Spread ◽

Diagnostic Capacity ◽

Antibody Levels ◽

Antibody Kinetics ◽

Kinetics Of

The COVID-19 pandemic and the fast global spread of the disease resulted in unprecedented decline in world trade and travel. A critical priority is, therefore, to quickly develop serological diagnostic capacity and identify individuals with past exposure to SARS-CoV-2. In this study serum samples obtained from 309 persons infected by SARS-CoV-2 and 324 of healthy, uninfected individuals as well as serum from 7 COVID-19 patients with 4–7 samples each ranging between 1–92 days post first positive PCR were tested by an “in house” ELISA which detects IgM, IgA and IgG antibodies against the receptor binding domain (RBD) of SARS-CoV-2. Sensitivity of 47%, 80% and 88% and specificity of 100%, 98% and 98% in detection of IgM, IgA and IgG antibodies, respectively, were observed. IgG antibody levels against the RBD were demonstrated to be up regulated between 1–7 days after COVID-19 detection, earlier than both IgM and IgA antibodies. Study of the antibody kinetics of seven COVID 19 patients revealed that while IgG levels are high and maintained for at least 3 months, IgM and IgA levels decline after a 35–50 days following infection. Altogether, these results highlight the usefulness of the RBD based ELISA, which is both easy and cheap to prepare, to identify COVID-19 patients even at the acute phase. Most importantly our results demonstrate that measuring IgG levels alone is both sufficient and necessary to diagnose past exposure to SARS-CoV-2.

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Pooled Saliva Specimens for SARS-CoV-2 Testing

Journal of Clinical Microbiology ◽

10.1128/jcm.02486-20 ◽

2020 ◽

Author(s):

Bidisha Barat ◽

Sanchita Das ◽

Valeria De Giorgi ◽

David K. Henderson ◽

Stacy Kopka ◽

...

Keyword(s):

Viral Load ◽

Screening Program ◽

High Viral Load ◽

Load Cycle ◽

Nasopharyngeal Swab ◽

Rt Pcr ◽

Viral Loads ◽

Viral Transport ◽

Average Loss ◽

Positive Agreement

We evaluated saliva (SAL) specimens for SARS-CoV-2 RT-PCR testing by comparison of 459 prospectively paired nasopharyngeal (NP) or mid-turbinate (MT) swabs from 449 individuals with the aim of using saliva for asymptomatic screening. Samples were collected in a drive-through car line for symptomatic individuals (N=380) and in the emergency department (ED) (N=69). The percent positive and negative agreement of saliva compared to nasopharyngeal swab were 81.1% (95% CI: 65.8% – 90.5%) and 99.8% (95% CI: 98.7% – 100%), respectively. The percent positive agreement increased to 90.0% (95% CI: 74.4% – 96.5%) when considering only samples with moderate to high viral load (Cycle threshold (Ct) for the NP <=34). Pools of five saliva specimens were also evaluated on three platforms: bioMérieux NucliSENS easyMAG with ABI 7500Fast (CDC assay), Hologic Panther Fusion®, and Roche COBAS® 6800. The average loss of signal upon pooling was 2-3 Ct values across the platforms. The sensitivity of detecting a positive specimen in a pool compared with testing individually was 94%, 90%, and 94% for CDC 2019-nCoV Real-Time RT-PCR, Panther Fusion® SARS-CoV-2 assay, and cobas® SARS-CoV-2 test respectively, with decreased sample detection trending with lower viral load. We conclude that although pooled saliva testing, as collected in this study, is not quite as sensitive as NP/MT testing, saliva testing is adequate to detect individuals with higher viral loads in an asymptomatic screening program, does not require swabs or viral transport media for collection, and may help to improve voluntary screening compliance for those individuals averse to various forms of nasal collections.

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Pooled Saliva Specimens for SARS-CoV-2 Testing

10.1101/2020.10.02.20204859 ◽

2020 ◽

Author(s):

Bidisha Barat ◽

Sanchita Das ◽

Valeria De Giorgi ◽

David K. Henderson ◽

Stacy Kopka ◽

...

Keyword(s):

Viral Load ◽

Screening Program ◽

High Viral Load ◽

Load Cycle ◽

Nasopharyngeal Swab ◽

Rt Pcr ◽

Lower Viral Load ◽

Viral Loads ◽

Viral Transport ◽

Positive Specimen

AbstractWe evaluated saliva (SAL) specimens for SARS-CoV-2 RT-PCR testing by comparison of 459 prospectively paired nasopharyngeal (NP) or mid-turbinate (MT) swabs from 449 individuals with the aim of using saliva for asymptomatic screening. Samples were collected in a drive-through car line for symptomatic individuals (N=380) and in the emergency department (ED) (N=69). The percent positive and negative agreement of saliva compared to nasopharyngeal swab were 81.1% (95% CI: 65.8% – 90.5%) and 99.8% (95% CI: 98.7% – 100%), respectively. The sensitivity increased to 90.0% (95% CI: 74.4% – 96.5%) when considering only samples with moderate to high viral load (Cycle threshold (Ct) for the NP <=34). Pools of five saliva specimens were also evaluated on three platforms: bioMérieux NucliSENS easyMAG with ABI 7500Fast (CDC assay), Hologic Panther Fusion, and Roche COBAS 6800. The median loss of signal upon pooling was 2-4 Ct values across the platforms. The sensitivity of detecting a positive specimen in a pool compared with testing individually was 100%, 93%, and 95% for CDC 2019-nCoV Real-Time RT-PCR, Panther Fusion® SARS-CoV-2 assay, and cobas® SARS-CoV-2 test respectively, with decreased sample detection trending with lower viral load. We conclude that although pooled saliva testing, as collected in this study, is not quite as sensitive as NP/MT testing, saliva testing is adequate to detect individuals with higher viral loads in an asymptomatic screening program, does not require swabs or viral transport media for collection, and may help to improve voluntary screening compliance for those individuals averse to various forms of nasal collections.

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Rapid diagnosis of SARS-CoV-2 pneumonia on lower respiratory tract specimens

BMC Infectious Diseases ◽

10.1186/s12879-021-06591-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Vanessa De Pace ◽

Patrizia Caligiuri ◽

Valentina Ricucci ◽

Nicola Nigro ◽

Barbara Galano ◽

...

Keyword(s):

Intensive Care ◽

Viral Load ◽

Lower Respiratory Tract ◽

Diagnostic Performance ◽

High Viral Load ◽

Load Cycle ◽

Rt Pcr ◽

Cycle Threshold ◽

Viral Loads ◽

Rapid Pcr

Abstract Background The ongoing SARS-CoV-2 pandemic requires the availability of accurate and rapid diagnostic tests, especially in such clinical settings as emergency and intensive care units. The objective of this study was to evaluate the diagnostic performance of the Vivalytic SARS-CoV-2 rapid PCR kit in lower respiratory tract (LRT) specimens. Methods Consecutive LRT specimens (bronchoalveolar lavage and bronchoaspirates) were collected from Intensive Care Units of San Martino Hospital (Genoa, Italy) between November 2020 and January 2021. All samples underwent RT-PCR testing by means of the Allplex™ SARS-CoV-2 assay (Seegene Inc., South Korea). On the basis of RT-PCR results, specimens were categorized as negative, positive with high viral load [cycle threshold (Ct) ≤ 30] and positive with low viral load (Ct of 31–35). A 1:1:1 ratio was used to achieve a sample size of 75. All specimens were subsequently tested by means of the Vivalytic SARS-CoV-2 rapid PCR assay (Bosch Healthcare Solutions GmbH, Germany). The diagnostic performance of this assay was assessed against RT-PCR through the 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). Sensitivity and specificity were 96% (95% CI: 86.5–98.9%) and 100% (95% CI: 86.7–100%), respectively. In samples with high viral loads, sensitivity was 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) on Vivalytic and RT-PCR, respectively (Fig. 1). NPV and PPV was 92.6% and 100%, respectively.Table 1 Demographic characteristics and data sample type of the study cases (N = 75) Male, N (%) 56 (74.6%) Age (yr), Median (IQR) 65 (31–81) BAS, N (%) 43 (57.3%) Negative 30.2% Positive—High viral load [Ct ≤ 30] 27.9% Positive—Low viral load [Ct 31–35] 41.9% BAL, N (%) 32 (42.7%) Negative 37.5% Positive—High viral load [Ct ≤ 30] 40.6% Positive—Low viral load [Ct 31–35] 21.9% Data were expressed as proportions for categorical variables. Specimens were categorized into negative, positive with high viral load [cycle threshold (Ct) ≤ 30] and positive with low viral load (Ct of 31–35). BAS bronchoaspirates, BAL bronchoalveolar lavage, Ct cycle threshold Conclusions Vivalytic SARS-CoV-2 can be used effectively on LRT specimens following sample liquefaction. It is a feasible and highly accurate molecular procedure, especially in samples with high viral loads. This assay yields results in about 40 min, and may therefore accelerate clinical decision-making in urgent/emergency situations.

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Detection of SARs CoV-2 during initial phase of pandemic from population of banas kantha district of Gujarat-India with special emphasis on pooled samples

IP International Journal of Medical Microbiology and Tropical Diseases ◽

10.18231/j.ijmmtd.2021.061 ◽

2021 ◽

Vol 7 (4) ◽

pp. 295-299

Author(s):

Hiren Patel ◽

Parijat N Goswami

Keyword(s):

Viral Load ◽

Age Groups ◽

High Viral Load ◽

Rt Pcr ◽

Viral Loads ◽

Corona Virus ◽

Asymptomatic Patients ◽

Care Workers ◽

Pcr Method ◽

Pharynx Swab

Corona virus (SARs CoV-2) has caused immense effect on morbidity and mortality of the population globally. We undertook this study as we are a part of one of the network laboratories of ICMR to test the patient’s sample by RT PCR for the ORF 1 ab gene of corona virus. : For a period of one and half months (14 April to 31 May 2020) we tested the nasopharynx and oro-pharynx swab samples sent to us in VTM from the assigned districts of Gujarat. All the samples were subjected to RT PCR method by following standard methods. Total of 9.04%(256/2833) population was positive and 4.73%(139/2833) belonged to age groups 21-40 and 2.33% (66/2833) to 41-60yrs. Above the age of 60yrs there were only 0.95% (22/2833) cases which were positive. It was advantageous to pool the samples. Out of the number of pools prepared, we reported around 80% negative and rest were positive in pools. The study also included association of viral load and infectivity. We found that 12% of the asymptomatic people and 5.1% of symptomatic individuals had high viral load. : It is seen that the incidence of Novel corona virus -19 detection by RT PCR is a reliable method and the establishment of the Ct value and infectivity of the patient to the health care workers and relatives needs to be taken care of. Also, the study presents asymptomatic patients having high viral loads being highly infective.

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Performance of the Innova SARS-CoV-2 antigen rapid lateral flow test in the Liverpool asymptomatic testing pilot: population based cohort study

BMJ ◽

10.1136/bmj.n1637 ◽

2021 ◽

pp. n1637 ◽

Cited By ~ 1

Author(s):

Marta García-Fiñana ◽

David M Hughes ◽

Christopher P Cheyne ◽

Girvan Burnside ◽

Mark Stockbridge ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Viral Load ◽

Predictive Value ◽

High Viral Load ◽

Test Results ◽

Chain Reaction ◽

Viral Loads ◽

Flow Test ◽

Polymerase Chain ◽

Lateral Flow Test

Abstract Objective To assess the performance of the SARS-CoV-2 antigen rapid lateral flow test (LFT) versus polymerase chain reaction testing in the asymptomatic general population attending testing centres. Design Observational cohort study. Setting Community LFT pilot at covid-19 testing sites in Liverpool, UK. Participants 5869 asymptomatic adults (≥18 years) voluntarily attending one of 48 testing sites during 6-29 November 2020. Interventions Participants were tested using both an Innova LFT and a quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR) test based on supervised self-administered swabbing at testing sites. Main outcome measures Sensitivity, specificity, and predictive values of LFT compared with RT-qPCR in an epidemic steady state of covid-19 among adults with no classic symptoms of the disease. Results Of 5869 test results, 22 (0.4%) LFT results and 343 (5.8%) RT-qPCR results were void (that is, when the control line fails to appear within 30 minutes). Excluding the void results, the LFT versus RT-qPCR showed a sensitivity of 40.0% (95% confidence interval 28.5% to 52.4%; 28/70), specificity of 99.9% (99.8% to 99.99%; 5431/5434), positive predictive value of 90.3% (74.2% to 98.0%; 28/31), and negative predictive value of 99.2% (99.0% to 99.4%; 5431/5473). When the void samples were assumed to be negative, a sensitivity was observed for LFT of 37.8% (26.8% to 49.9%; 28/74), specificity of 99.6% (99.4% to 99.8%; 5431/5452), positive predictive value of 84.8% (68.1% to 94.9%; 28/33), and negative predictive value of 93.4% (92.7% to 94.0%; 5431/5814). The sensitivity in participants with an RT-qPCR cycle threshold (Ct) of <18.3 (approximate viral loads >10 6 RNA copies/mL) was 90.9% (58.7% to 99.8%; 10/11), a Ct of <24.4 (>10 4 RNA copies/mL) was 69.4% (51.9% to 83.7%; 25/36), and a Ct of >24.4 (<10 4 RNA copies/mL) was 9.7% (1.9% to 23.7%; 3/34). LFT is likely to detect at least three fifths and at most 998 in every 1000 people with a positive RT-qPCR test result with high viral load. Conclusions The Innova LFT can be useful for identifying infections among adults who report no symptoms of covid-19, particularly those with high viral load who are more likely to infect others. The number of asymptomatic adults with lower Ct (indicating higher viral load) missed by LFT, although small, should be considered when using single LFT in high consequence settings. Clear and accurate communication with the public about how to interpret test results is important, given the chance of missing some cases, even at high viral loads. Further research is needed to understand how infectiousness is reflected in the viral antigen shedding detected by LFT versus the viral loads approximated by RT-qPCR.

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

10.1101/2021.12.16.21267912 ◽

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.

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SARS-CoV-2 Persistence in Immunocompromised Children

10.22541/au.162448803.31733691/v1 ◽

2021 ◽

Author(s):

Susan Dolan ◽

Jean Mulcahy Levy ◽

Angla Moss ◽

Kelly Pearce ◽

Samuel Dominguez ◽

...

Keyword(s):

Viral Load ◽

Median Time ◽

Immunosuppressive Treatment ◽

Viral Persistence ◽

High Viral Load ◽

Viral Loads ◽

Mild Disease ◽

Kaplan Meier ◽

Diagnostic Panel ◽

Event Times

Introduction/Objectives: We evaluated the length of time immunocompromised children (ICC) remain positive for SARS-CoV-2, identified factors associated with viral persistence and determined cycle threshold (CT) values of children with viral persistence as a surrogate of viral load. Methods: We conducted a retrospective cohort study of ICC at a pediatric hospital from March 2020-2021. Immunocompromised status was defined as primary, secondary or acquired due to medical comorbidities/immunosuppressive treatment. The primary outcome was time to first-of-two consecutive negative SARS-CoV-2 Polymerase chain reaction (PCR) tests at least 24 hours apart. Testing of sequential clinical specimens from the same subject was conducted using the Centers for Disease Control (CDC) 2019-nCoV Real-Time RT-PCR Diagnostic Panel assay. Descriptive statistics, Kaplan-Meier curve median event times and log-rank-sum tests were used to compare outcomes between groups. Results: Ninety-one children met inclusion criteria. Median age was 15.5 years (IQR 8-18 yrs), 64% were male, 58% were white, and 43% were Hispanic/Latinx. Most (67%) were tested in outpatient settings and 58% were asymptomatic. The median time to two negative tests was 42 days (IQR 25.0,55.0), with no differences in median time by illness presentation or level of immunosuppression. Seven children had >1 sample available for repeat testing, and 5/7 (71%) children had initial CT values of <30, (moderate to high viral load); 4 children had CT values of <30 3-4 weeks later, suggesting persistent moderate to high viral loads. Conclusions: Most ICC with SARS-CoV-2 infection had mild disease, with prolonged viral persistence >6 weeks and moderate to high viral load.

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

10.21203/rs.3.rs-684790/v1 ◽

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.

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Evaluation of saliva sampling procedures for SARS-CoV-2 diagnostics reveals differential sensitivity and association with viral load

10.1101/2020.10.06.20207902 ◽

2020 ◽

Author(s):

Pieter Mestdagh ◽

Michel Gillard ◽

Marc Arbyn ◽

Jean-Paul Pirnay ◽

Jeroen Poels ◽

...

Keyword(s):

Viral Load ◽

High Risk ◽

Health Professionals ◽

High Viral Load ◽

Sampling Procedure ◽

Differential Sensitivity ◽

Collection Method ◽

Viral Loads ◽

Saliva Collection ◽

Sampling Procedures

AbstractNasopharyngeal sampling has been the preferential collection method for SARS-CoV-2 diagnostics. Alternative sampling procedures that are less invasive and do not require a healthcare professional would be more preferable for patients and health professionals. Saliva collection has been proposed as such a possible alternative sampling procedure. We evaluated the sensitivity of SARS-CoV-2 testing on two different saliva collection devices (spitting versus swabbing) compared to nasopharyngeal swabs in over 2500 individuals that were either symptomatic or had high-risk contacts with infected individuals. We observed an overall poor sensitivity in saliva for SARS-CoV-2 detection (30.8% and 22.4% for spitting and swabbing, respectively). However, when focusing on individuals with medium to high viral load, sensitivity increased substantially (97.0% and 76.7% for spitting and swabbing, respectively), irrespective of symptomatic status. Our results suggest that saliva cannot readily replace nasopharyngeal sampling for SARS-CoV-2 diagnostics but may enable identification of cases with medium to high viral loads.

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