Positive Reverse Transcription Polymerase Chain Reaction Test Research Articles

Examination of SARS-CoV-2 RNA in joint synovial fluid of patients with COVID-19 and acute knee arthritis.

It has not yet been fully established that there is coronavirus disease 2019 (COVID-19) involvement in the synovial fluid and it remains a topic of debate. The aim of this study was to evaluate the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in knee joint synovial fluid of patients with COVID-19. This retrospective study was conducted with an initial screening of patients who were admitted to a tertiary pandemic hospital due to COVID-19 symptoms, and underwent treatment for COVID-19 between March and June 2020. A total of 2476 patients were hospitalized or received treatment for a possible diagnosis of COVID-19. While the RT-PCR test was positive in 318 patients (12.8%), 2158 (87.2%) were computed tomography positive but reverse transcription-polymerase chain reaction (RT-PCR) negative. Twelve patients were consulted due to acute joint effusion. Of five patients with knee joint effusion and a positive RT-PCR test, the synovial tissue RT-PCR test was positive in only one patient. This paper is the first to show the presence of SARS-CoV-2 in synovial fluid. This can be considered of importance for the determination and elimination of the route of transmission, thereby preventing further development and spread of the disease.

Fukuchi-Manabe Score for Infection Control Measures During the Very Early COVID-19 Pandemic Period When Access to Reverse Transcription-Polymerase Chain Reaction Testing Was Poor in Japan: A Single-Center Observational Prospective Cohort Study.

During the early stages of the COVID-19 pandemic in Japan, access to reverse transcription-polymerase chain reaction (RT-PCR) testing was limited. All patients with COVID-19 required hospitalization, and isolation of suspected COVID-19 patients had not yet been implemented. With the recently acquired evidence on COVID-19, it is important to develop a risk stratification system for isolation rooms in the context of limited resources for better resource management. This study aimed to develop and validate a COVID-19 risk-scoring strategy, the Fukuchi-Manabe score, to safely stratify and manage isolation rooms, personal protective equipment (PPE), and RT-PCR testing in the context of limited RT-PCR testing and a short supply of PPE. This single-center prospective study consecutively enrolled suspected COVID-19 adult inpatients between March 1 and August 31, 2020. The primary and secondary outcomes were a positive RT-PCR test and the occurrence of nosocomial infections during the study period, respectively. Factors related to patient history, symptoms, chest computed tomography findings, and laboratory data suggestive of COVID-19 were scored, totaled, and divided into four categories ("probable," "possible," "less likely," and "non-suspicious") based on the likelihood of COVID-19. Sensitivity, specificity, and positive and negative predictive values were evaluated for each probability category. Twenty of 224 inpatients were positive on the RT-PCR test, including 18 "probable" patients (90.0%), one "possible" patient, and one "less likely" patient. The area under the curve (AUC) (95% confidence interval: 0.841-0.977), sensitivity, and specificity were 0.909, 90.0%, and 80.4%, respectively. The positive and negative predictive values and accuracy for the "probable" category were 0.90, 0.80, and 0.82, respectively. The mean and standard deviation of AUCs, validated by bootstrap analysis, were 0.910±0.034. No nosocomial infections were observed. The Fukuchi-Manabe score will be helpful when other novel pathogens emerge in the future before the availability of genetic testing methods.

COVID-19 Breakthrough Infections in Vaccinated Patients With CLL in Israel.

COVID-19 Breakthrough Infections in Vaccinated Patients With CLL in Israel.

Incidence and risk factors of SARS-CoV-2 infection among workers in a public health laboratory in Tunisia

The aim of this study was to measure the extent of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among workers at the Institut Pasteur de Tunis (IPT), a public health laboratory involved in the management of the COVID-19 pandemic in Tunisia, and to identify risk factors for infection in this occupational setting. A cross-sectional survey was conducted on IPT workers not vaccinated against coronavirus disease 2019 (COVID-19). Participants completed a questionnaire that included a history of reverse transcription-polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2 infection. Immunoglobulin G antibodies against the receptor-binding domain of the spike antigen (anti-S-RBD IgG) and the nucleocapsid protein (anti-N IgG) of the SARS-CoV-2 virus were detected by enzyme-linked immunoassay (ELISA). A multivariate analysis was used to identify factors significantly associated with SARS-CoV-2 infection. A total of 428 workers were enrolled in the study. The prevalence of anti-S-RBD and/or anti-N IgG antibodies was 32.9% [28.7-37.4]. The cumulative incidence of SARS-CoV-2 infection (positive serology and/or previous positive RT-PCR test) was 40.0% [35.5-44.9], while the proportion with asymptomatic infection was 32.9%. One-third of the participants with RT-PCR-confirmed infection tested seronegative more than 90 days postinfection. Participants aged over 40 and laborers were more susceptible to infection (adjusted OR [AOR] = 1.65 [1.08-2.51] and AOR = 2.67 [1.45-4.89], respectively), while tobacco smokers had a lower risk of infection (AOR = 0.54 [0.29-0.97]). The SARS-CoV-2 infection rate among IPT workers was not significantly different from that detected concurrently in the general population. Hence, the professional activities conducted in this public health laboratory did not generate additional risk to that incurred outside the institute in day-to-day activities.

Comparison of Cepheid Xpert Xpress SARS-CoV-2 Assay with Standard RTPCR Test for Detection of COVID-19 Infection: A Retrospective Cohort Study

Introduction: Real time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) test, the gold standard test for Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) detection, is a tedious process and requires proficient workforce. Accurate and fast test results may permit more efficient use of protective and isolation resources and allow rapid therapeutic interventions. Aim: To evaluate the analytical performance characteristics of the Cepheid Xpert Xpress SARS-CoV-2 test, a rapid, automated molecular test for SARS-CoV-2 with gold standard RT-PCR test. Materials and Methods: This retrospective cohort study was conducted in Virus Research and Diagnostic Laboratory (VRDL) in Department of Microbiology at GGS Medical College, Faridkot from January 2021-June 2021. A total of 100 nasopharyngeal samples, collected from clinically suspected Coronavirus Diseae2019 (COVID-19) cases admitted at GGSMC during 1st January30th June 2021 were tested both by Xpert assay and RT-PCR test simultaneously, taking RT-PCR as the gold standard test. The data was analysed by MedCalc® statistical software version 19.6.4., and sensitivity, specificity, predictive values, likelihood ratios and the agreement between the two tests were calculated. Results: The mean age of the study participants was 46 years. Of these, 55 were males and 45 were females. The overall sample sensitivity and specificity of the Xpert assay were both 100% and there was perfect agreement across specimens, if authors, set a cut-off Cycle threshold-value (Ct-value) at 40 cycles for Xpert. Of 100 samples, 32 were positive for SARSCoV-2 by either of the tests and 68 were negative. Xpert assay could detect 100% positive cases and RT-PCR test could detect 84.37% positive cases. Out of the 32 samples which were positive by Xpert assay, 5 (15.62%) samples had a Ctvalue greater than 40. Conclusion: The Xpert assay found to be useful as a point-ofcare test in acute scenario, where rapid and authentic diagnosis is essential, but do not have expertise and infrastructure to perform RT-PCR.

The Value of Spiral Chest Computed Tomography Scan in the Diagnosis of Asymptomatic Coronavirus Carriers among Paranasal Sinus and Pharynx Surgery Candidates.

Introduction The nasopharynx and oropharynx are the main colonization sites of coronavirus. Therefore, patients with paranasal sinuses and pharyngeal problems (ear, nose, and throat [ENT] patients) predispose coronavirus infection. Ear, nose, and throat patients with concomitant asymptomatic coronavirus infection may develop severe pneumonia following surgical procedures. As a result, presurgical screening for coronavirus infection is a substantial concern.Objective We evaluated the usefulness of a spiral chest computed tomography (CT) scan in the diagnosis of asymptomatic coronavirus infection in the presurgical assessment of ENT patients Methods In this study, candidates of paranasal sinus or pharyngeal surgery were evaluated for coronavirus infection. Patients with neither history of coronavirus disease 2019 (COVID-19) nor compatible symptoms and signs were screened for asymptomatic coronavirus infection. These patients composed two groups: the first group underwent a reverse transcription polymerase chain reaction (RT-PCR) test of nasopharyngeal sample and spiral chest CT scan, but for the second one, only the latter was performed. Results In the first group, which consisted of 106 patients, 11 (10.4%) cases had positive RT-PCR test results, and 17 (16%) patients showed positive findings in favor of coronavirus infection in the spiral chest CT scan. In the second group, which consisted of 173 patients, 34 (19.7%) cases had positive chest CT scan results. Conclusion The chest CT scan has a valuable role in the early diagnosis of asymptomatic coronavirus carriers in patients highly predisposed to infection, especially in low resource areas, where the RT-PCR test is unavailable.

Clinical significance of chest CT for the exclusion of COVID-19 in pre-admission screening: Is it worthwhile using chest CT with reverse-transcription polymerase chain reaction test?

BackgroundA single reverse-transcription polymerase chain reaction (RT-PCR) test is not sufficient to exclude COVID-19 in hospital pre-admission screening. However, repeated RT-PCR tests are time-consuming. This study investigates the utility of chest computed tomography (CT) for COVID-19 screening in asymptomatic patients.MethodsBetween April 2020 and March 2021, RT-PCR testing and chest CT were performed to screen COVID-19 in 10 823 asymptomatic patients prior to admission. Chest CT findings were retrospectively evaluated using the reporting system of the Radiological Society of North America. Using RT-PCR results as a reference, we assessed the diagnostic efficacy of chest CT during both the low- and high-prevalence periods of the COVID-19 pandemic.ResultsFollowing a positive RT-PCR test, 20 asymptomatic patients (0.18%) were diagnosed with COVID-19; in the low-prevalence period, 5 of 6556 patients (0.076%) were positive; and in the high-prevalence period, 15 of 4267 patients (0.35%) were positive. Of the 20 asymptomatic COVID-19 positive patients, chest CT results were positive for COVID-19 pneumonia in 8 patients. Chest CT results were false-positive in 185 patients (1.7% false-positive rate, and 60% false-negative rate). Pneumonia that was classified as a “typical appearance” of COVID-19 reported as false-positives in 36 of 39 patients (92.3%). Across the study period, the diagnostic efficacy of “typical appearance” on chest CT were characterized by a sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of 15%, 99.7%, 99.7%, 7.7%, and 99.8%; 20%, 99.6%, 99.6%, 4%, and 99.9%; and 13.3%, 99.7%, 99.7%, 14.3%, and 99.7%, in the entire study, low-, and high-prevalence periods, respectively.ConclusionsAddition of chest CT to RT-PCR testing provides no benefit to the detection of COVID-19 in asymptomatic patients.

Lung Ultrasound using a Handheld Device to Diagnose COVID-19 in the Emergency Department

The Coronavirus Disease 2019 (COVID-19) pandemic has critically struck healthcare systems and burdened emergency services. To date, there is no accurate and rapid point-of-care diagnostic test. This study aimed to investigate Lung Ultrasound (LUS) against Reverse Transcription-Polymerase Chain Reaction (RT-PCR) test in suspected COVID-19 patients presenting to the emergency department. In 20 eligible patients (mean age ± standard deviation, 49 ± 15 years), 12 had a positive RT-PCR test and undergone an LUS examination over 12 lung zones using a handheld ultrasound device. Each zone was semiquantitatively scored according to the Lung Ultrasound Scoring System (LUSS) from 0 to 3 based on the severity of findings (pleural line irregularity, B-lines, consolidations) and documented the presence of light beam artifacts. A second blinded reader scored the images to investigate interreader reproducibility. The LUSS score had a modest diagnostic performance at 66.6% [95% Confidence Interval (CI), 34.9–90.0%] sensitivity and 75.0% (95% CI, 34.9–96.8%) specificity. The light beam artifact was more prevalent and sensitive to COVID-19 patients with 81.8% (95% CI, 48.2–97.7%) sensitivity and 75.0% (95% CI, 34.9–96.8%) specificity. LUS had an almost perfect interreader reproducibility for LUSS (Kendall’s W = 0.961; 95% CI, 0.894–0.985) and light beam artifact (Cohen’s κ = 0.890; 95% CI, 0.683–1.00). Overall, LUS using handheld devices can offer a safe, reproducible, rapid, and feasible first-line tool for detecting COVID-19 patients in emergency departments. The light beam artifact was more sensitive and specific to COVID-19 patients and can be useful for effectively triaging suspected cases.

The diagnostic performance of deep-learning-based CT severity score to identify COVID-19 pneumonia.

Objective:To determine the diagnostic accuracy of a deep-learning (DL)-based algorithm using chest computed tomography (CT) scans for the rapid diagnosis of coronavirus disease 2019 (COVID-19), as compared to the reference standard reverse-transcription polymerase chain reaction (RT-PCR) test.Methods:In this retrospective analysis, data of COVID-19 suspected patients who underwent RT-PCR and chest CT examination for the diagnosis of COVID-19 were assessed. By quantifying the affected area of the lung parenchyma, severity score was evaluated for each lobe of the lung with the DL-based algorithm. The diagnosis was based on the total lung severity score ranging from 0 to 25. The data were randomly split into a 40% training set and a 60% test set. Optimal cut-off value was determined using Youden-index method on the training cohort.Results:A total of 1259 patients were enrolled in this study. The prevalence of RT-PCR positivity in the overall investigated period was 51.5%. As compared to RT-PCR, sensitivity, specificity, positive predictive value, negative predictive value and accuracy on the test cohort were 39.0%, 80.2%, 68.0%, 55.0% and 58.9%, respectively. Regarding the whole data set, when adding those with positive RT-PCR test at any time during hospital stay or “COVID-19 without virus detection”, as final diagnosis to the true positive cases, specificity increased from 80.3% to 88.1% and the positive predictive value increased from 68.4% to 81.7%.Conclusion:DL-based CT severity score was found to have a good specificity and positive predictive value, as compared to RT-PCR. This standardized scoring system can aid rapid diagnosis and clinical decision making.Advances in knowledge:DL-based CT severity score can detect COVID-19-related lung alterations even at early stages, when RT-PCR is not yet positive.

The Relationship Between Sudden Sensorineural Hearing Loss, Vestibular Neuritis, and Infection With COVID-19

Introduction: This study aimed to investigate the relationship between sudden sensorineural hearing loss, vestibular neuritis, and infection with COVID-19. Materials and Methods: In this study, a total of 56 Iranians (32 females and 24 males) with a Mean±SD age of 45.12±14 years were studied in Tehran City, Iran. Individuals diagnosed with Sudden Sensorineural Hearing Loss (SSNHL) or vestibular neuritis based on definitive diagnostic criteria were included in the study. The methodology comprised four sections of underlying Sudden Hearing Loss,, auditory and vestibular inspection, SARS-CoV-2 Reverse Transcription-Polymerase Chain Reaction (RT-PCR) test, and statistical analysis. Also, the videonystagmography test was used in participants with vertigo to diagnose vestibular neuritis. Pure tone audiometry confirmed SSNHL in some patients with a complaint of hearing loss. Furthermore, tuning fork, Rinne and Weber tests were also performed. Results: The results of SARS-CoV-2 RT-PCR in 56 subjects showed that eight subjects (22.2%) with vestibular neuritis and two with SSNHL (10%) had a positive RT-PCR test. The Chi- square and Fisher exact-tests with a 95% confidence interval revealed no statistically significant (P>0.05) relationship between COVID-19 infection and vestibular neuritis or SSNHL. Conclusion: The present study showed no statistically significant relationship between audiovestibular disorders and positive SARS-CoV-2 RT-PCR test. However, the possibility of this relationship cannot be ruled out, and there is a need for studies with larger sample sizes.

Epidemiology and Clinical Outcomes of Patients with Confirmed Influenza in Mashhad, Iran in 2019

Background: Influenza is a contagious and acute viral disease caused by influenza viruses involving upper and lower respiratory tract system, especially in the cold seasons. Children aged less than 5 years old, elderly people, immunocompromised patients, pregnant women, and people with certain health conditions are at a higher risk for the disease and severe complications. Objectives: Due to the serious complications of influenza in certain groups, it is important to know which group of people are more at risk and need prevention strategies. This study aimed to investigate the patients with confirmed influenza, identify the people who are at a higher risk for infection, and assess the clinical outcomes of disease among patients. Methods: In this cross-sectional and descriptive study, we studied the files of all patients with confirmed influenza referred to the health centers in Mashhad, Iran, during autumn and winter of 2019 when influenza virus was prevalent. The disease was confirmed by reverse transcription polymerase chain reaction (RT-PCR) method. We studied all registered data related to the flu, including gender, age, residency, history of vaccination, risk factors, complications, and clinical outcomes. Results: In this study, 2977 patients (3% outpatients vs. 97% hospitalized) with flu like syndrome were tested by RT-PCR for influenza. Out of 84 outpatients, only two cases were positive for influenza. Among hospitalized patients, 80 cases (51% male vs. 49% female; age range: 1 - 87 years) had a positive RT-PCR test, and influenza type A was seen in 95% of cases. Pneumonia was the most common complication. Death happened in 29 (35.36%) patients and three (33.33%) cases with risk factors. The highest number of influenza patients (31 [37.8%]) had been reported from district No. 3 of Mashhad municipality, which is a crowded place and near the holy shrine. Conclusions: The results showed a high prevalence of complication and death among hospitalized patients, especially among those who did not have a risk factor for influenza viruses. Comprehensive vaccination programs and promotion of knowledge about transmission routes are two important measures for disease prevention and lower death rates.

Dynamics of Reverse Transcription-Polymerase Chain Reaction and Serologic Test Results in Children with SARS-CoV-2 Infection

ObjectivesTo determine the time to reverse transcription-polymerase chain reaction (RT-PCR) negativity after the first positive RT-PCR test, factors associated with longer time to RT-PCR negativity, proportion of children seroconverting after proven severe acute respiratory syndrome coronavirus 2 infection, and factors associated with the lack of seroconversion.Study designThe Epidemiological Study of Coronavirus in Children of the Spanish Society of Pediatrics is a multicenter study conducted in Spanish children to assess the characteristics of coronavirus disease 2019. In a subset of patients, 3 serial RT-PCR tests on nasopharyngeal swab specimens were performed after the first RT-PCR test, and immunoglobulin G serology for severe acute respiratory syndrome coronavirus 2 antibodies was performed in the acute and follow-up (<14 and ≥14 days after diagnosis) phase.ResultsIn total, 324 patients were included in the study. The median time to RT-PCR negativity was 17 days (IQR, 8-29 days), and 35% of patients remained positive more than 4 weeks after the first RT-PCR test. The probability of RT-PCR negativity did not differ across groups defined by sex, disease severity, immunosuppressive drugs, or clinical phenotype. Globally, 24% of children failed to seroconvert after infection. Seroconversion was associated with hospitalization, persistence of RT-PCR positivity, and days of fever.ConclusionsTime to RT-PCR negativity was long, regardless of the severity of symptoms or other patient features. This finding should be considered when interpreting RT-PCR results in a child with symptoms, especially those with mild symptoms. Seroprevalence and postimmunization studies should consider that 11 in 4 infected children fail to seroconvert.

In COVID-19 patients, low 25-hydroxyvitamin D level in serum is associated with longer viral clearance time and higher risk of intensive care unit admission

PurposeThis study aims to investigate the association between vitamin D measured in serum 25 hydroxyvitamin D [25(OH)D] and outcomes of COVID-19 patients in Bahrain. This paper hypothesized that lower serum 25(OH)D concentration in COVID 19 patients is associated with longer viral clearance time (VCT) and higher risk of admission to the intensive care unit (ICU).Design/methodology/approachThis study used a retrospective cohort design of patients admitted to Salmaniya Medical Complex, Manama, Kingdom of Bahrain, from February to June 2020. This study included patients with positive, confirmed COVID-19 diagnosis made using reverse transcription-polymerase chain reaction (RT-PCR), World Health Organization diagnosis manual and local diagnostic guidelines. Primary outcome measures were: VCT measured as the time in days between the first positive RT-PCR test result and the first of two consecutive negative RT-PCR results on recovery and admission need to ICU.FindingsA total of 450 patients were analyzed; mean age was 46.4 ± 12.4 years and 349 (78%) were men. Mean 25(OH)D concentration was 41.7 ± 23.7 nmol/L for the entire sample. Severe vitamin D deficiency (<25 nmol/L) was present in 20%, mild-to-moderate deficiency (25–50 nmol/L) in 55%, insufficiency (50 to <75 nmol/L) in 18% and sufficiency (=75 nmol/L) in 7%. The mean VCT was 12.9 ± 8.2 days. Multivariate linear regression analysis showed that severe vitamin D deficiency was associated with longer VCT, with an average of three extra days after correction for age and sex (β = 3.1; p = 0.001). Multinomial regression analysis showed that vitamin D deficiency was associated with an 83% increased risk of admission to ICU after correction for age and sex (odds ratio = 1.8; p = 0.03).Originality/valueThe results showed that severe vitamin D deficiency was associated with longer recovery time from COVID-19. Low serum 25(OH)D is associated with increased need for critical care in an ICU. Large-scale randomized controlled trials are necessary to further investigate the complex association between vitamin D and COVID-19 infection.

Comparison of computed tomography (CT) findings with RT‐PCR in the diagnosis of COVID‐19 in children

AimThis study aimed to compare chest computed tomography (CT) findings with reverse‐transcription polymerase chain reaction (RT‐PCR) test results in children with probable or definitive diagnosis of coronavirus disease 2019 (COVID‐19).MethodsIn this retrospective archive study, pediatric patients who were followed up in the hospital with a possible or definitive diagnosis of COVID‐19 and who had chest CT at presentation were included. CT scan images of the patients were reinterpreted by a pediatric radiologist and compared with their RT‐PCR test results.ResultsOf the total of 89 patients, 33 had negative and 56 had positive RT‐PCR tests. The presence of pulmonary lesions and consolidation was statistically significantly higher in the RT‐PCR negative group than in the RT‐PCR positive group (p = 0.037 and 0.001, respectively). Lobe involvement of 0%–25% was higher in the RT‐PCR positive group (p = 0.001), and lobe involvements of 25%–50% and 50%–75% were significantly higher in the RT‐PCR negative group (p = 0.001 and 0.005, respectively). Central and perihilar involvement was found to be statistically significant in the RT‐PCR negative group (p = 0.008 and 0.005, respectively).ConclusionChest CT findings may provide some clues in predicting RT‐PCR positivity in children with a probable diagnosis of COVID‐19. Lobe involvement percentage of up to 25% is a finding in favor of patients with positive RT‐PCR test, whereas 25%–75% lobe involvement, central and perihilar involvement, and consolidation can be interpreted in favor of patients with negative RT‐PCR test.

SARS-CoV-2 Transmission Risk Among National Basketball Association Players, Staff, and Vendors Exposed to Individuals With Positive Test Results After COVID-19 Recovery During the 2020 Regular and Postseason

Clinical data are lacking regarding the risk of viral transmission from individuals who have positive reverse-transcription-polymerase chain reaction (RT-PCR) SARS-CoV-2 test results after recovery from COVID-19. To describe case characteristics, including viral dynamics and transmission of infection, for individuals who have clinically recovered from SARS-CoV-2 infection but continued to have positive test results following discontinuation of isolation precautions. This retrospective cohort study used data collected from June 11, 2020, to October 19, 2020, as part of the National Basketball Association (NBA) closed campus occupational health program in Orlando, Florida, which required daily RT-PCR testing and ad hoc serological testing for SARS-CoV-2 IgG antibodies. Nearly 4000 NBA players, staff, and vendors participated in the NBA's regular and postseason occupational health program in Orlando. Persistent positive cases were those who recovered from a documented SARS-CoV-2 infection, satisfied US Centers for Disease Control and Prevention criteria for discontinuation of isolation precautions, and had at least 1 postinfection positive RT-PCR test(s) result. Person-days of participation in indoor, unmasked activities that involved direct exposure between persistent positive cases and noninfected individuals. Transmission of SARS-CoV-2 following interaction with persistent positive individuals, as measured by the number of new COVID-19 cases in the Orlando campus program. Among 3648 individuals who participated, 36 (1%) were persistent positive cases, most of whom were younger than 30 years (24 [67%]) and male (34 [94%]). Antibodies were detected in 33 individuals (91.7%); all remained asymptomatic following the index persistent positive RT-PCR result. Cycle threshold values for persistent positive RT-PCR test results were typically above the Roche cobas SARS-CoV-2 limit of detection. Cases were monitored for up to 100 days (mean [SD], 51 [23.9] days), during which there were at least 1480 person-days of direct exposure activities, with no transmission events or secondary infections of SARS-CoV-2 detected (0 new cases). In this retrospective cohort study of the 2020 NBA closed campus occupational health program, recovered individuals who continued to test positive for SARS-CoV-2 following discontinuation of isolation were not infectious to others. These findings support time-based US Centers of Disease Control and Prevention recommendations for ending isolation.

LB-12. SARS-CoV-2 RNA and Antibodies among People Experiencing Homelessness and Staying in Shelters or Outdoor Encampments in Denver, Colorado, May-July 2020

BackgroundThe COVID-19 pandemic has disproportionately affected people experiencing homelessness (PEH) residing in shelters. Initial and regular testing of PEH in communities with moderate or substantial SARS-CoV-2 transmission may limit spread in shelters. We analyzed factors associated with positive SARS-CoV-2 RNA and antibody tests for PEH staying in shelters or encampments in Denver, Colorado.MethodsIn May 2020, Denver Public Health collaborated with local leaders to identify 4 homeless shelters and 3 outdoor encampments for voluntary, universal SARS-CoV-2 testing. At each testing event, a short questionnaire including sociodemographic factors and symptoms was administered to PEH who consented to testing. SARS-CoV-2 RNA testing by reverse transcription polymerase chain reaction (RT-PCR) was performed on nasopharyngeal swabs; antibody testing was performed on venous blood samples. PEH reporting a prior positive RT-PCR test were not retested but were eligible for antibody testing. Statistical calculations were performed with an α of 0.05; all tests were two-sided.ResultsFrom June 2–July 28, 2020, 931 PEH were approached. A total of 863 RT-PCR tests were performed at 14 testing events, and 334 antibody tests were performed at 5 testing events. Overall, 604 and 259 RT-PCR tests were conducted in 4 shelters and 3 encampments, respectively; 189 and 145 antibody tests were conducted in 3 shelters and 2 encampments, respectively. PEH tested in shelters were older, more often men, less often Native American, and less likely to report COVID-19 symptoms than those tested at encampments (Table 1). Overall, 9% of PEH tested in shelters tested positive for SARS-CoV-2 compared to 3% of PEH tested in encampments (p=0.002); 8% of men had positive RT-PCR results compared to 2% of women (p=0.03) (Table 2). PEH tested at shelters had a higher percentage of detectable SARS-CoV-2 antibodies than those tested in encampments (24% vs 8%, p=0.0002; Table 3). Neither RT-PCR nor antibody test results differed significantly by race or ethnicity.Table 1. Demographics of participants residing in encampments compared with shelters in Denver, Colorado, May-July 2020 (n=931) Table 2. Comparison of participants testing positive or negative for SARS-CoV-2 RT-PCR* by location and demographics, in Denver, Colorado, May-July 2020 Table 3. Comparison of participants testing positive or negative for antibodies against SARS-CoV-2 by location and demographics in Denver, Colorado, May-July 2020 ConclusionA greater percentage of PEH tested positive for both SARS-CoV-2 RNA and antibodies at shelters than encampments, suggesting that continued assessment of mitigation strategies in shelters should be a priority.Disclosures All Authors: No reported disclosures

CT FINDINGS IN INITIAL RT-PCR NEGATIVE TESTING COVID 19: BASED ON STUDY IN A LARGEST TERTIARY CARE CENTRE OF CENTRAL INDIA.

SUMMARY STATEMENT CT imaging findings in patients of suspected 2019-nCoV infection, who have initial negative results of reverse transcription–polymerase chain reaction (RT-PCR) testing. OBJECTIVE The purpose of this study is to explore the diagnostic value of CT over RT-PCR in the diagnosis of corona virus disease (COVID-19) pneumonia, especially for patients who have initial negative results of reverse transcription–polymerase chain reaction (RT-PCR) testing. MATERIALS AND METHODS Patients with suspected COVID-19 pneumonia from April 1, 2020, to September 30, 2020, were included. They are initially underwent RT-PCR followed by HRCT thorax after 1 day of negative initial RT-PCR testing. The imaging findings were obtained and compared with CT findings of those patients who have confirmed initial reverse transcription–polymerase chain reaction (RT-PCR) testing. RESULTS Total sixty (40 men, 20 women) patients who have initial negative RT-PCR testing but are highly suspicious for 2019-nCoV infection were included in our study and their age range between 22 years to 70 years. In our study most of the findings were seen involved the multiple( 70%) lobes in both lungs. The main CT features were ground-glass opacity (90%) and consolidation (60%) with a sub pleural (100%) and peri hilar or central distribution. The other CT features included air bronchograms (60%), vascular enlargement and interlobular septal thickening (50%), tree in bud appearance and pleural effusions (10%). when CT of patient with initial negative RT-PCR test were compared with CT of patients with initial positive RT-PCR test , it was found that most of the findings like ground glass opacities and consolidatory changes were also likely present in these group (p&gt;0.05). CONCLUSION Chest CT is an important tools for screening and diagnosing the patients who are initial negative RT-PCR however they are highly suspicious and having symptoms like 2019-nCoV infection.

Clinical application of the COVID-19 Reporting and Data System (CO-RADS) in patients with suspected SARS-CoV-2 infection: observational study in an emergency department

• CO-RADS improves the risk classification by 65.8% in patients affected by COVID-19. • CO-RADS combined with RT-PCR presents an AUC of 0.98 for patients with COVID-19. • CO-RADS improves the risk classification by 82.1% in patients not affected by COVID-19.

The Issue of Recurrently Positive Patients Who Recovered From COVID-19 According to the Current Discharge Criteria: Investigation of Patients from Multiple Medical Institutions in Wuhan, China.

The current discharge criteria for COVID-19 require that patients have two consecutive negative results for RT-PCR detection. Here, we observed that recurrently positive RT-PCR test results in patients with three consecutive negative results (3xNegRPos, 5.4%) were significantly decreased compared with those in patients with two consecutive negative results (2xNegRPos, 20.6%); such patients reported positive RT-PCR test results within 1 to 12 days after meeting the discharge criteria. These results confirmed that many recovered patients could show a positive RT-PCR test result, and most of these patients could be identified by an additional RT-PCR test prior to discharge.