scholarly journals Comparison of Anterior Nares Viral Loads in Asymptomatic and Symptomatic Individuals Diagnosed with SARS-CoV-2 in a University Screening Program

2022 ◽  
Author(s):  
Samantha M. Hall ◽  
Lena Landaverde ◽  
Christopher Gill ◽  
Grace Midori Yee ◽  
Madison Sullivan ◽  
...  
Keyword(s):  
Viral Load ◽  
High Throughput Screening ◽  
Screening Program ◽  
Nasal Congestion ◽  
Clinical Team ◽  
Asymptomatic Group ◽  
Gold Standard Method ◽  
Skin Changes ◽  
Viral Loads ◽  
Asymptomatic Patients

RT-qPCR has been used as the gold standard method for detecting SARS-CoV-2 since early in the pandemic. At our university based high throughput screening program, we test all members of our community weekly. RT-qPCR cycle threshold (CT) values are inversely proportional to the amount of viral RNA in a sample, and thus are a proxy for viral load. We hypothesized that CT values would be higher, and thus the viral loads at the time of diagnosis would be lower in individuals who were infected with the virus but remained asymptomatic throughout the course of the infection. We collected the N1 and N2 CT values from 1633 SARS-CoV-2 positive RT-qPCR tests of individuals sampled between August 7, 2020, and March 18, 2021, at the BU Clinical Testing Laboratory. We matched this data with symptom reporting data from our clinical team. We found that asymptomatic patients had CT values significantly higher than symptomatic individuals on the day of diagnosis. Symptoms were followed by the clinical team for 10 days post the first positive test. Within the entire population, 78.1% experienced at least one symptom during surveillance by the clinical team (n=1276/1633). Of those experiencing symptoms, the most common symptoms were nasal congestion (73%, n=932, 1276), cough (60.0%, n=761/1276), fatigue (59.0%, n=753/1276), and sore throat (53.1%, n=678/1276). The least common symptoms were diarrhea (12.5%, n=160/1276), dyspnea on exertion (DOE) (6.9%, n=88/1276), foot or skin changes (including rash) (4.2%, n=53/1276), and vomiting (2.1%, n= 27/1276). Presymptomatic individuals, those who were not symptomatic on the day of diagnosis but became symptomatic over the following 10 days, had CT values higher for both N1 (median= 27.1, IQR 20.2- 32.9) and N2 (median=26.6, IQR 20.1-32.8) than the symptomatic group N1 (median= 21.8, IQR 17.2- 29.4) and N2 (median= 21.4, IQR 17.3- 28.9) but lower than the asymptomatic group N1 (median=29.9, IQR 23.6-35.5) and N2 (median= 30.0, IQR 23.1- 35.7). This study supports the hypothesis that viral load in the anterior nares on the day of diagnosis is a measure of disease intensity at that time.

scholarly journals Differential Kinetics of Cycle Threshold Values during Admission by Symptoms among Patients with Mild COVID-19: A Prospective Cohort Study

2021 ◽  
Vol 18 (15) ◽  
pp. 8181
Author(s):  
Teppei Sakano ◽  
Mitsuyoshi Urashima ◽  
Hiroyuki Takao ◽  
Kohei Takeshita ◽  
Hiroe Kobashi ◽  
...  
Keyword(s):  
Cohort Study ◽  
Viral Load ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Polymerase Chain Reaction Test ◽  
Cycle Threshold ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Asymptomatic Individuals ◽  
Chain Reaction Test

In the coronavirus disease 2019 (COVID-19) pandemic, more than half of the cases of transmission may occur via asymptomatic individuals, which makes it difficult to contain. However, whether viral load in the throat during admission is different between asymptomatic and symptomatic patients is not well known. By conducting a prospective cohort study of patients with asymptomatic or mild COVID-19, cycle threshold (Ct) values of the polymerase chain reaction test for COVID-19 were examined every other day during admission. The Ct values during admission increased more steadily in symptomatic patients and febrile patients than in asymptomatic patients, with significance (p = 0.01 and p = 0.004, respectively), although the Ct values as a whole were not significantly different between the two groups. Moreover, the Ct values as a whole were higher in patients with dysosmia/dysgeusia than in those without it (p = 0.02), whereas they were lower in patients with a headache than those without (p = 0.01). Patients who were IgG-positive at discharge maintained higher Ct values, e.g., more than 35, during admission than those with IgG-negative (p = 0.03). Assuming that viral load and Ct values are negatively associated, the viral loads as a whole and their changes by time may be different by symptoms and immune reaction, i.e., IgG-positive at discharge.

scholarly journals Viral Load of SARS-CoV-2 in Respiratory Aerosols Emitted by COVID-19 Patients while Breathing, Talking, and Singing

2021 ◽  
Author(s):  
Kristen K. Coleman ◽  
Douglas Jie Wen Tay ◽  
Kai Sen Tan ◽  
Sean Wei Xiang Ong ◽  
Than The Son ◽  
...  
Keyword(s):  
Viral Load ◽  
Significant Role ◽  
N Gene ◽  
Exhaled Breath ◽  
Indoor Environments ◽  
Future Studies ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Gene Copies ◽  
Study Participants

Background: Multiple SARS-CoV-2 superspreading events suggest that aerosols play an important role in driving the COVID-19 pandemic. However, the detailed roles of coarse (>5μm) and fine (≤5μm) respiratory aerosols produced when breathing, talking, and singing are not well-understood. Methods: Using a G-II exhaled breath collector, we measured viral RNA in coarse and fine respiratory aerosols emitted by COVID-19 patients during 30 minutes of breathing, 15 minutes of talking, and 15 minutes of singing. Results: Among the 22 study participants, 13 (59%) emitted detectable levels of SARS-CoV-2 RNA in respiratory aerosols, including 3 asymptomatic patients and 1 presymptomatic patient. Viral loads ranged from 63 - 5,821 N gene copies per expiratory activity. Patients earlier in illness were more likely to emit detectable RNA, and loads differed significantly between breathing, talking, and singing. The largest proportion of SARS-CoV-2 RNA copies was emitted by singing (53%), followed by talking (41%) and breathing (6%). Overall, fine aerosols constituted 85% of the viral load detected in our study. Virus cultures were negative. Conclusions: Fine aerosols produced by talking and singing contain more SARS-CoV-2 copies than coarse aerosols and may play a significant role in the transmission of SARS-CoV-2. Exposure to fine aerosols should be mitigated, especially in indoor environments where airborne transmission of SARS-CoV-2 is likely to occur. Isolating viable SARS-CoV-2 from respiratory aerosol samples remains challenging, and whether this can be more easily accomplished for emerging SARS-CoV-2 variants is an important enquiry for future studies.

scholarly journals Evaluation of the SARS-CoV-2 positivity ratio and upper respiratory tract viral load among asymptomatic individuals screened before hospitalization or surgery in Flanders, Belgium

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259908
Author(s):  
Laura Heireman ◽  
Steven Abrams ◽  
Peggy Bruynseels ◽  
Reinoud Cartuyvels ◽  
Lize Cuypers ◽  
...  
Keyword(s):  
Viral Load ◽  
Respiratory Tract ◽  
Age Group ◽  
Test Results ◽  
Rt Pcr ◽  
Median Viral Load ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Positivity Ratio ◽  
Second Wave

Introduction The incidence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections in the Belgian community is mainly estimated based on test results of patients with coronavirus disease (COVID-19)-like symptoms. The aim of this study was to investigate the evolution of the SARS-CoV-2 reverse transcriptase polymerase chain reaction (RT-PCR) positivity ratio and distribution of viral loads within a cohort of asymptomatic patients screened prior hospitalization or surgery, stratified by age category. Materials/Methods We retrospectively studied data on SARS-CoV-2 real-time RT-PCR detection in respiratory tract samples of asymptomatic patients screened pre-hospitalization or pre-surgery in nine Belgian hospitals located in Flanders over a 12-month period (1 April 2020–31 March 2021). Results In total, 255925 SARS-CoV-2 RT-PCR test results and 2421 positive results for which a viral load was reported, were included in this study. An unweighted overall SARS-CoV-2 real-time RT-PCR positivity ratio of 1.27% was observed with strong spatiotemporal differences. SARS-CoV-2 circulated predominantly in 80+ year old individuals across all time periods except between the first and second COVID-19 wave and in 20–30 year old individuals before the second COVID-19 wave. In contrast to the first wave, a significantly higher positivity ratio was observed for the 20–40 age group in addition to the 80+ age group compared to the other age groups during the second wave. The median viral load follows a similar temporal evolution as the positivity rate with an increase ahead of the second wave and highest viral loads observed for 80+ year old individuals. Conclusion There was a high SARS-CoV-2 circulation among asymptomatic patients with a predominance and highest viral loads observed in the elderly. Moreover, ahead of the second COVID-19 wave an increase in median viral load was noted with the highest overall positivity ratio observed in 20–30 year old individuals, indicating they could have been the hidden drivers of this wave.

scholarly journals Relationships between Viral Load and the Clinical Course of COVID-19

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 304
Author(s):  
Hiroyuki Tsukagoshi ◽  
Daisuke Shinoda ◽  
Mariko Saito ◽  
Kaori Okayama ◽  
Mitsuru Sada ◽  
...  
Keyword(s):  
Viral Load ◽  
Early Stage ◽  
Fatal Case ◽  
Epidemiological Data ◽  
High Viral Load ◽  
Viral Loads ◽  
Severe Stage ◽  
Asymptomatic Patients ◽  
Positive Rate

To predict the clinical outcome of coronavirus disease-2019 (COVID-19), we examined relationships among epidemiological data, viral load, and disease severity. We examined viral loads of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) in fatal (15 cases), symptomatic/survived (133 cases), and asymptomatic cases (138 cases) using reverse transcription quantitative real-time PCR (RT-qPCR). We examined 5768 nasopharyngeal swabs (NPS) and attempted to detect the SARS-CoV-2 genome using RT-qPCR. Among them, the viral genome was detected using the method for the 370 NPS samples with a positive rate of 6.4%. A comparison of each age showed that the fatal case was higher than the survived case and asymptomatic patients. Survived cases were older than asymptomatic patients. Notably, the viral load in the fatal cases was significantly higher than in symptomatic or asymptomatic cases (p < 0.05). These results suggested that a high viral load of the SARS-CoV-2 in elderly patients at an early stage of the disease results in a poor outcome. We should, therefore, intervene early to prevent a severe stage of the disease in such cases.

scholarly journals Pooled Saliva Specimens for SARS-CoV-2 Testing

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.

scholarly journals COVID-19 Outbreak at a Geriatric Rehabilitation Facility: The Silent Threat of Asymptomatic Patients with High Viral Loads

Geriatrics ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 95
Author(s):  
Pauline Putallaz ◽  
Laurence Senn ◽  
Wanda Bosshard ◽  
Christophe J. Büla
Keyword(s):  
Viral Load ◽  
Case Series ◽  
Screening Strategy ◽  
Geriatric Rehabilitation ◽  
Retrospective Case ◽  
Viral Loads ◽  
Atypical Symptoms ◽  
Rehabilitation Facility ◽  
Asymptomatic Patients ◽  
Rapid Transmission

Data about outbreaks of nosocomial COVID-19 disease within geriatric rehabilitation facilities are scarce. In this retrospective case series analysis, we describe such an outbreak, determine the proportion of a-/presymptomatic patients, the median time before symptom onset among presymptomatic patients and investigate whether the viral load differs between patients with and without symptoms. Typical and atypical symptoms were retrieved from the electronic medical records of patients who tested positive for COVID-19 disease during their stay at a 95-bed geriatric rehabilitation facility. The viral load at the time of diagnosis was estimated on cycle threshold values of the rRT-PCR test. Overall, 34 patients (median age, 87 years; range, 66–98; 67% female) tested positive for SARS-CoV-2. During the same period, 19 health care workers were also diagnosed with COVID-19. Among the 27 patients who provided consent, 20 (74%) were symptomatic at the time of testing. Among the remaining seven patients, six developed symptoms after a median of 2 days. A viral load > 106 copies/mL was observed in 20 out of the 27 patients, including five out of the seven initially asymptomatic patients. The rapid transmission of SARS-CoV-2 and the prevalence of initially asymptomatic patients with high viral loads support an extended screening strategy at such facilities.

scholarly journals Pooled Saliva Specimens for SARS-CoV-2 Testing

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.

scholarly journals Clinical importance of reporting SARS-CoV-2 viral loads across the different stages of the COVID-19 pandemic

2020 ◽  
Author(s):  
Milo Moraz ◽  
Damien Jacot ◽  
Matthaios Papadimitriou-Olivgeris ◽  
Laurence Senn ◽  
Gilbert Greub ◽  
...  
Keyword(s):  
Viral Load ◽  
Universal Screening ◽  
Clinical Importance ◽  
Screening Strategy ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Admission Screening ◽  
Polymerase Chain

On April 25th, corresponding to the first deconfinement phase after the end of the lockdown in Switzerland, a universal admission screening strategy for COVID-19 was introduced in our hospital. All patients, including asymptomatic patients were tested for SARS-CoV-2 by quantitative reverse transcription polymerase chain reaction (RT-PCR). In addition to a qualitative answer, providing viral load values to the RT-PCR results not only helped the clinician to evaluate the stage of the infection but addressed patient contagiousness and guided infection control decisions. Here, we discuss the importance of reporting viral load values when a shift from a symptomatic to a universal screening strategy was performed.

scholarly journals Transmissibility of COVID-19 depends on the viral load around onset in adult and symptomatic patients

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243597
Author(s):  
Hitoshi Kawasuji ◽  
Yusuke Takegoshi ◽  
Makito Kaneda ◽  
Akitoshi Ueno ◽  
Yuki Miyajima ◽  
...  
Keyword(s):  
Viral Load ◽  
Linear Regression ◽  
University Hospital ◽  
Sample Collection ◽  
Initial Sample ◽  
Median Viral Load ◽  
Secondary Transmission ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Non Linear

Objective To investigate the relationship between viral load and secondary transmission in novel coronavirus disease 2019 (COVID-19). Methods Epidemiological and clinical data were obtained from immunocompetent laboratory-confirmed patients with COVID-19 who were admitted to and/or from whom viral loads were measured at Toyama University Hospital. Using a case-control approach, index patients who transmitted the disease to at least one other patient were analysed as “cases” (index patients) compared with patients who were not the cause of secondary transmission (non-index patients, analysed as “controls”). The viral load time courses were assessed between the index and non-index symptomatic patients using non-linear regression employing a standard one-phase decay model. Results In total, 28 patients were included in the analysis. Median viral load at the initial sample collection was significantly higher in symptomatic than in asymptomatic patients and in adults than in children. Among symptomatic patients (n = 18), non-linear regression models showed that the estimated viral load at onset was higher in the index than in the non-index patients (median [95% confidence interval]: 6.6 [5.2–8.2] vs. 3.1 [1.5–4.8] log copies/μL, respectively). In adult (symptomatic and asymptomatic) patients (n = 21), median viral load at the initial sample collection was significantly higher in the index than in the non-index patients (p = 0.015, 3.3 vs. 1.8 log copies/μL, respectively). Conclusions High nasopharyngeal viral loads around onset may contribute to secondary transmission of COVID-19. Viral load may help provide a better understanding of why transmission is observed in some instances, but not in others, especially among household contacts.

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

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.

Sign in / Sign up

Export Citation Format

Share Document