Upper respiratory viral load in asymptomatic individuals and mildly symptomatic patients with SARS-CoV-2 infection

BackgroundAsymptomatic individuals with SARS-CoV-2 infection have viable viral loads and have been linked to several transmission cases. However, data on the viral loads in such individuals are lacking. We assessed the viral loads in asymptomatic individuals with SARS-CoV-2 infection in comparison with those in symptomatic patients with COVID-19.MethodsStudy participants were recruited from a community facility designated for the isolation of patients with mild COVID-19 in South Korea. The presence of symptoms was evaluated with a questionnaire-based survey. Viral loads in the upper respiratory tract were measured with real-time reverse transcription-PCR (RT-PCR) targeting the E, RdRp and N genes of SARS-CoV-2, with a cycle threshold (Ct) value of 40 for determining positivity.ResultsIn 213 patients with SARS-CoV-2 infection, 41 (19%) had remained asymptomatic from potential exposure to laboratory confirmation and admission; of them, 39 (95%) underwent follow-up RT-PCR testing after a median 13 days. In 172 symptomatic patients, 144 (84%) underwent follow-up RT-PCR testing. Twenty-one (54%) asymptomatic individuals and 92 (64%) symptomatic patients tested positive for SARS-CoV-2 at follow-up. Asymptomatic individuals and symptomatic patients did not show any significant differences in the mean Ct values of the E (31.15 vs 31.43; p>0.99), RdRp (32.26 vs 32.93; p=0.92) and N (33.05 vs 33.28; p>0.99) genes.ConclusionApproximately one-fifth of the individuals without severe symptoms were asymptomatic, and their viral loads were comparable to those in symptomatic patients. A large proportion of mildly symptomatic patients with COVID-19 or asymptomatic individuals with SARS-CoV-2 showed persistent positive upper respiratory RT-PCR results at follow-up.

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The natural history and transmission potential of asymptomatic SARS-CoV-2 infection

10.1101/2020.04.27.20082347 ◽

2020 ◽

Cited By ~ 17

Author(s):

Nguyen Van Vinh Chau ◽

Vo Thanh Lam ◽

Nguyen Thanh Dung ◽

Lam Minh Yen ◽

Ngo Ngoc Quang Minh ◽

...

Keyword(s):

Natural History ◽

Ho Chi Minh City ◽

Rt Pcr ◽

Transmission Potential ◽

Viral Loads ◽

Symptomatic Group ◽

History Of ◽

Asymptomatic Individuals ◽

A Prospective Study

ABSTRACTBackgroundLittle is known about the natural history of asymptomatic SARS-CoV-2 infection or its contribution to infection transmission.MethodsWe conducted a prospective study at a quarantine centre for COVID-19 in Ho Chi Minh City, Vietnam. We enrolled quarantined people with RT-PCR-confirmed SARS-CoV-2 infection, collecting clinical data, travel and contact history, and saliva at enrolment and daily nasopharyngeal throat swabs (NTS) for RT-PCR testing. We compared the natural history and transmission potential of asymptomatic and symptomatic individuals.ResultsBetween March 10th and April 4th, 2020, 14,000 quarantined people were tested for SARS-CoV-2; 49 were positive. Of these, 30 participated in the study: 13(43%) never had symptoms and 17(57%) were symptomatic. 17(57%) participants acquired their infection outside Vietnam. Compared with symptomatic individuals, asymptomatic people were less likely to have detectable SARS-CoV-2 in NTS samples collected at enrolment (8/13 (62%) vs. 17/17 (100%) P=0.02). SARS-CoV-2 RNA was detected in 20/27 (74%) available saliva; 7/11 (64%) in the asymptomatic and 13/16 (81%) in the symptomatic group (P=0.56). Analysis of the probability of RT-PCR positivity showed asymptomatic participants had faster viral clearance than symptomatic participants (P<0.001 for difference over first 19 days). This difference was most pronounced during the first week of follow-up. Two of the asymptomatic individuals appeared to transmit the infection to up to four contacts.ConclusionsAsymptomatic SARS-CoV-2 infection is common and can be detected by analysis of saliva or NTS. NTS viral loads fall faster in asymptomatic individuals, but they appear able to transmit the virus to others.

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Viral load in upper respiratory tract of COVID-19 patients detected by digital PCR

10.21203/rs.3.rs-29834/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Jiankang Zhao ◽

Haibo Li ◽

Hui Li ◽

Qiaoling Wu ◽

Ke Wu ◽

...

Keyword(s):

Viral Load ◽

Respiratory Tract ◽

Digital Pcr ◽

Upper Respiratory Tract ◽

Rt Pcr ◽

Lung Lesions ◽

Viral Loads ◽

Ct Value ◽

Upper Respiratory ◽

Close Contacts

Abstract Background: Upper respiratory tract specimens are widely applicable for the diagnosis of COVID-19. To date, no study has analyzed the actual viral loads in upper respiratory tract and its relationship with the severity of lung lesions, Ct value of RT-PCR and transmission capacity in COVID-19 patients.Methods: We retrospectively enrolled nine COVID-19 patients. Clinical data and close contacts of these patients were investigated. Respiratory samples were tested for SARS-CoV-2 with both normal RT-PCR and droplet digital PCR.Results: All the COVID-19 patients complicated with pneumonia. Viral loads in nasopharyngeal swabs were accurately quantified, and they had no direct correspondence with the severity of lung lesions. The Cycle Threshold (Ct) value of RT-PCR was approximately consistent with the absolute quantification of digital PCR. The spearman correlation coefficient between them was -0.952 with P value < 0.001. Close contacts of patients with very low viral load or no detected virus were not infected.Conclusions: Viral loads in nasopharyngeal swabs, could not predict the severity of lung lesions revealed by CT in COVID-19 patients. The infectious capacity of patients with low or absent viral load in upper respiratory tract was relatively weak, and wearing mask might be helpful for lower its spread.

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Sensitivity of RT-PCR testing of upper respiratory tract samples for SARS-CoV-2 in hospitalised patients: a retrospective cohort study

Wellcome Open Research ◽

10.12688/wellcomeopenres.16342.1 ◽

2020 ◽

Vol 5 ◽

pp. 254

Author(s):

Thomas C. Williams ◽

Elizabeth Wastnedge ◽

Gina McAllister ◽

Ramya Bhatia ◽

Kate Cuschieri ◽

...

Keyword(s):

Respiratory Tract ◽

Clinical Diagnosis ◽

Gold Standard ◽

Upper Respiratory Tract ◽

Rt Pcr ◽

Reverse Transcription Pcr ◽

Hospitalised Patients ◽

Increased Sensitivity ◽

Upper Respiratory ◽

Pcr Test

Background: This study aimed to determine the sensitivity and specificity of reverse transcription PCR (RT-PCR) testing of upper respiratory tract (URT) samples from hospitalised patients with coronavirus disease 2019 (COVID-19), compared to the gold standard of a clinical diagnosis. Methods: All URT RT-PCR testing for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in NHS Lothian, Scotland, United Kingdom between the 7th of February and 19th April 2020 (inclusive) was reviewed, and hospitalised patients were identified. All URT RT-PCR tests were analysed for each patient to determine the sequence of negative and positive results. For those who were tested twice or more but never received a positive result, case records were reviewed, and a clinical diagnosis of COVID-19 allocated based on clinical features, discharge diagnosis, and radiology and haematology results. For those who had a negative RT-PCR test but a clinical diagnosis of COVID-19, respiratory samples were retested using a multiplex respiratory panel, a second SARS-CoV-2 RT-PCR assay, and a human RNase P control. Results: Compared to the gold standard of a clinical diagnosis of COVID-19, the sensitivity of a single upper respiratory tract RT-PCR for COVID-19 was 82.2% (95% confidence interval 79.0-85.1%). The sensitivity of two upper respiratory tract RT-PCR tests increased sensitivity to 90.6% (CI 88.0-92.7%). A further 2.2% and 0.9% of patients who received a clinical diagnosis of COVID-19 were positive on a third and fourth test; this may be an underestimate of the value of further testing as the majority of patients 93.0% (2999/3226) only had one or two URT RT-PCR tests. Conclusions: The sensitivity of a single RT-PCR test of URT samples in hospitalised patients is 82.2%. Sensitivity increases to 90.6% when patients are tested twice. A proportion of cases with clinically defined COVID-19 never test positive on URT RT-PCR despite repeat testing.

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Is it enough for COVID-19 screening test? Limitation of swab test and general characteristics of mild symptom patients

Science Progress ◽

10.1177/00368504211026152 ◽

2021 ◽

Vol 104 (2) ◽

pp. 003685042110261

Author(s):

Sungwoo Choi ◽

Hyo Jeong Choi ◽

Ho Jung Kim

Keyword(s):

Screening Test ◽

Community Treatment ◽

Upper Respiratory Tract ◽

Test Results ◽

Rt Pcr ◽

Pcr Assay ◽

Positive Rate ◽

Upper Respiratory ◽

Polymerase Chain ◽

Discharge Criteria

The most common method for SARS-CoV-2 testing is throat or nasal swabbing by real-time reverse transcription polymerase chain reaction (RT-PCR) assay. In South Korea, drive-through swab test is used for screening system and community treatment centers (CTCs), which admit and treat confirmed COVID-19 patients with mild symptoms, are being used. This retrospective study was conducted on patients admitted to a CTC on March 6, 2020. A total of 313 patients were admitted. The nasal and throat swabs were collected from the upper respiratory tract, and a sputum test was performed to obtain lower respiratory samples. The positive rate of the first set of test, sputum test was higher than that of the swab test ( p = 0.011). In the second set of test, 1 week after the first ones, the rate of positive swab tests was relatively high ( p = 0.026). In the first set of test, 66 of 152 (43.4%) patients showed 24-h consecutive negative swab test results, when the sputum test results were considered together, that number fell to 29 patients (19.1%) ( p < 0.001). Also, in the second set of test, 63 of 164 (38.4%) patients met the discharge criteria only when the swab test was considered; that number fell to 30 (18.3%) when the sputum test results were also considered ( p < 0.001). Using the swab test alone is insufficient for screening test and discharge decision. Patients who may have positive result in the sputum test can be missed.

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Effects of procalcitonin testing on antibiotic use and clinical outcomes in patients with upper respiratory tract infections. An individual patient data meta-analysis

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2017-0252 ◽

2017 ◽

Vol 56 (1) ◽

Cited By ~ 7

Author(s):

Jonas Odermatt ◽

Natalie Friedli ◽

Alexander Kutz ◽

Matthias Briel ◽

Heiner C. Bucher ◽

...

Keyword(s):

Respiratory Tract ◽

Antibiotic Therapy ◽

Respiratory Tract Infections ◽

Meta Analysis ◽

Antibiotic Exposure ◽

Upper Respiratory Tract ◽

Upper Respiratory ◽

Restricted Activity ◽

Tract Infections

AbstractBackground:Several trials found procalcitonin (PCT) helpful for guiding antibiotic treatment in patients with lower respiratory tract infections and sepsis. We aimed to perform an individual patient data meta-analysis on the effects of PCT guided antibiotic therapy in upper respiratory tract infections (URTI).Methods:A comprehensive search of the literature was conducted using PubMed (MEDLINE) and Cochrane Library to identify relevant studies published until September 2016. We reanalysed individual data of adult URTI patients with a clinical diagnosis of URTI. Data of two trials were used based on PRISMA-IPD guidelines. Safety outcomes were (1) treatment failure defined as death, hospitalization, ARI-specific complications, recurrent or worsening infection at 28 days follow-up; and (2) restricted activity within a 14-day follow-up. Secondary endpoints were initiation of antibiotic therapy, and total days of antibiotic exposure.Results:In total, 644 patients with a follow up of 28 days had a final diagnosis of URTI and were thus included in this analysis. There was no difference in treatment failure (33.1% vs. 34.0%, OR 1.0, 95% CI 0.7–1.4; p=0.896) and days with restricted activity between groups (8.0 vs. 8.0 days, regression coefficient 0.2 (95% CI –0.4 to 0.9), p=0.465). However, PCT guided antibiotic therapy resulted in lower antibiotic prescription (17.8% vs. 51.0%, OR 0.2, 95% CI 0.1–0.3; p<0.001) and in a 2.4 day (95% CI –2.9 to –1.9; p<0.001) shorter antibiotic exposure compared to control patients.Conclusions:PCT guided antibiotic therapy in the primary care setting was associated with reduced antibiotic exposure in URTI patients without compromising outcomes.

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Perioperative Respiratory Adverse Events in General Anesthesia Among Pediatric Surgical Patients in Comprehensive Specialized Hospitals in Northwest Ethiopia, 2020; A Cross-Sectional Follow-Up

10.21203/rs.3.rs-138101/v1 ◽

2021 ◽

Author(s):

Yophtahe Woldegerima ◽

Desalegn Muche ◽

Wubie Birlie ◽

Habtu Adane ◽

Misganaw Mengie

Keyword(s):

Adverse Events ◽

Respiratory Tract Infections ◽

Northwest Ethiopia ◽

Surgical Patients ◽

Upper Respiratory Tract Infections ◽

Upper Respiratory Tract ◽

Cross Sectional ◽

Upper Respiratory ◽

Tract Infections

Abstract Introduction: Perioperative respiratory adverse events (PRAEs) are the most frequent complications in pediatrics which frequently result in morbidity and mortality. They are accountable for 75% of perioperative critical incidents and 33% of cardiac arrests. The occurrence and severity of PRAEs depends on the natures of surgery, anesthesia & patient’s status.Objective: To assess the incidence and factors associated with PRAEs in general anesthesia among pediatric surgical patients at the University of Gondar and Tibebe-Ghion Comprehensive Hospital and Specialized Hospitals, Northwest Ethiopia, 2020.Methods: After obtaining the ethical approval, a hospital-based prospective cross-sectional follow-up study was conducted among pediatric surgical patients who underwent variety of surgical operations. A total of 225 patients were included. The associations between independent variables and the outcome variables were determined at 95% CI with the Chi-squared test, Fisher–exact test, bivariate, and multivariate logistic regression. Hosmer-Lemeshow test was used to assess the goodness of fit. Variables with a p-value < 0.05 were considered significant.Results: The incidence of PRAEs among 210 (93.3% response rate) pediatrics surgical patients was 26.2% (95% CI: 20.5, 30.9). A total of 129 episodes of PRAEs were observed. Most of the adverse events (89 (69.0%)) were occurred postoperatively. Desaturation was found to be the predominant adverse event which was occurred 61 (47.3%) times. Age < 1 year (AOR: 3.6, 95% CI: 1.3, 10.0), ASA ≥ 3 (AOR: 5.2, 95% CI: 1.9, 22.9), upper respiratory tract infections (AOR: 7.6, 95% CI: 1.9, 30.2), presence of secretions in the upper airway (AOR: 4.8, 95% CI: 1.4, 15.9) and airway related procedures (AOR: 6.0, 95% CI: 1.5, 24.1) were significantly associated PRAEs.Conclusions: The incidence of PRAEs among pediatric surgical patients was relatively high (26.2%). Especially, the postoperative phase is the most critical time for the occurrence of PRAEs and desaturation was the predominant adverse event. Age less than a year, presence of upper respiratory tract infections, presence of secretions in the upper airways, ASA ≥ 3 and airway related procedures were associated with PRAEs. Clinicians should carry out effective risk assessment, optimization and adequate preparation for the management of perioperative respiratory adverse events.

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Asymptomatic COVID-19 Adult Outpatients identified as Significant Viable SARS-CoV-2 Shedders

10.21203/rs.3.rs-403751/v1 ◽

2021 ◽

Author(s):

Marie Glenet ◽

Anne-Laure Lebreil ◽

Laetitia Heng ◽

Yohan N’Guyen ◽

Ittah Meyer ◽

...

Keyword(s):

Respiratory Tract ◽

Control Measures ◽

Upper Respiratory Tract ◽

Rna Detection ◽

Viral Loads ◽

Infection Control Measures ◽

Infected Adult ◽

Asymptomatic Adult ◽

Upper Respiratory ◽

Kinetics Of

Abstract Differential kinetics of RNA loads and infectious viral levels in the upper respiratory tract between asymptomatic and symptomatic SARS-CoV-2 infected adult outpatients remain unclear limiting recommendations that may guide clinical management, infection control measures and occupational health decisions. In the present investigation, 496 (2.5%) of 17,911 French adult outpatients were positive for an upper respiratory tract SARS-CoV-2 RNA detection by a quantitative RT-PCR assay, of which 180 (36.3%) were COVID-19 asymptomatic. Of these adult asymptomatic viral shedders, 84.4% had mean to high RNA viral loads (Ct values<30) which median value was significantly higher than that observed in symptomatic subjects (P=0.029), and 50.6% were positive by cell culture assays of their upper respiratory tract specimens. Our findings indicate that COVID-19 asymptomatic adult outpatients are significant viable SARS-CoV-2 shedders in their upper respiratory tract playing a major potential role as SARS-CoV-2 transmitters in various epidemiological transmission chains, promoting COVID-19 resurgence in populations.

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Verification and diagnostic evaluation of the RealStar® Middle East respiratory syndrome coronavirus (N gene) reverse transcription-PCR kit 1.0

Future Microbiology ◽

10.2217/fmb-2019-0067 ◽

2019 ◽

Vol 14 (11) ◽

pp. 941-948 ◽

Cited By ~ 5

Author(s):

Leonie-Sophie Hecht ◽

Angeles Jurado-Jimenez ◽

Markus Hess ◽

Hussein El Halas ◽

Gregor Bochenek ◽

...

Keyword(s):

Middle East ◽

Reverse Transcription ◽

Diagnostic Procedure ◽

Middle East Respiratory Syndrome ◽

Diagnostic Evaluation ◽

N Gene ◽

Rt Pcr ◽

Reverse Transcription Pcr ◽

Confirmatory Assay ◽

Pcr Targeting

Aim: We report the diagnostic evaluation of a confirmatory reverse transcription-PCR (RT-PCR) kit targeting the Middle East respiratory syndrome coronavirus (MERS-CoV) N gene. Material & methods: 33 patient samples from two collections sites in Riyadh, Saudi Arabia, which were pre-characterized via real-time RT-PCR targeting MERS-CoV orf1a and upE, and were tested using the MERS-CoV N gene, as a confirmatory assay. This diagnostic procedure follows a two-step diagnostics scheme, recommended by the WHO. Results: 18/33 samples tested positive, 11/33 tested negative for MERS-CoV RNA and 2/33 showed uncertain results. Conclusion: The results suggest, that the RealStar® MERS-CoV (N gene) RT-PCR kit 1.0 can be considered a suitable and reliable confirmatory assay in combination with the RealStar MERS-CoV RT-PCR kit 1.0 according to the diagnostic scheme recommended by WHO.

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Guttural pouch mycosis in a donkey (Equus asinus): a case report

Veterinární Medicína ◽

10.17221/3011-vetmed ◽

2010 ◽

Vol 55 (No. 11) ◽

pp. 561-565 ◽

Cited By ~ 12

Author(s):

F. Laus ◽

E. Paggi ◽

M. Cerquetella ◽

D. Spaziante ◽

A. Spaterna ◽

...

Keyword(s):

Clinical Presentation ◽

Present Report ◽

Topical Therapy ◽

Clinical Feature ◽

Upper Respiratory Tract ◽

Equus Asinus ◽

Upper Respiratory ◽

Physiological Peculiarity ◽

Main Distinguishing Feature

Guttural pouch mycosis is an emergency disease of the upper respiratory tract in equine species. In the present report a case of guttural pouch mycosis in a female, seven year-old pregnant donkey is described. A serious dyspnea which necessitated tracheotomy and preceding epistaxis was the most important clinical feature of guttural pouch mycosis in the donkey. A full and rapid effectiveness of the topical therapy, the protocol for which is described, is the main distinguishing feature with regard to treatment. In the Authors' knowledge a detailed description of clinical features, treatment and follow up of guttural pouch mycosis in a donkey is not available in the scientific literature. The anatomical and physiological peculiarity of donkeys could explain some of the differences with horses in clinical presentation and therapeutic management.

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Effects of individually chosen homoeopathic medicines on recurrent URTI in children

British Homeopathic Journal ◽

10.1016/s0007-0785(96)80018-4 ◽

1996 ◽

Vol 85 (01) ◽

pp. 4-14

Author(s):

J. Blommers ◽

D.J. Kuik ◽

L. Feenstra ◽

P.D. Bezemer ◽

E.S.M. De Lange-De Klerk

Keyword(s):

Clinical Trial ◽

University Hospital ◽

Controlled Clinical Trial ◽

Upper Respiratory Tract ◽

Eligibility Criteria ◽

Double Blind ◽

Upper Respiratory ◽

The University ◽

Current Standards

AbstractThe effects of homoeopathic medicines on children suffering from recurrent upper respiratory tract infection (URTI) were studied in a randomized double-blind placebo-controlled clinical trial conducted at the paediatric outpatients department of the university hospital of the Vrije Universiteit in Amsterdam from 1987 to 1992.The study was designed to meet both the requirements of proper homoeopathic practice and the current standards of a clinical trial. The purpose of a randomized placebo-controlled double-blind trial is to identify the effects of the agents under investigation by equalizing the effects of other factors that may influence outcome.The object of the trial, eligibility criteria, follow-up period, treatments and concurrent interventions, data collection and effect measures are discussed in the light of homoeopathic thinking.

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