Comparison of the sensitivity of rapid tests FCoV Ab (Vet Expert) and PCR in the diagnosis of feline infectious peritonitis (FIP) in cats with the effusive form of the disease

The aim of the study was to determine the usefulness of FCoV Ab rapid serological tests in the diagnosis of the effusive form of FIP in cats. The cats included in the study were divided into two groups. The study group consisted of 40 cats with a strain of FCoV causing FIP (the presence of the M1058L mutation) in the abdominal fluid determined using PCR. The control group consisted of 15 cats with ascites caused by factors other than FCoV infection. Serological examination demonstrated the presence of antibodies to feline coronavirus in 28 out of 40 samples of the fluid collected from animals included in the study group, which constituted 70.0% of the tested samples. No antibodies to coronavirus were identified in any of the peritoneal fluid samples collected from the cats included in the control group using rapid immunochromatographic tests. The results obtained in our own studies demonstrated that the serological test ensured very high probability, especially in the detection of infected animals, as well as, although with a slightly lower probability, in the exclusion of the presence of FIP virus infection in the samples of fluid collected from the peritoneal cavity.

Performance of point-of care molecular and antigen-based tests for SARS-CoV-2: a living systematic review and meta-analysis.

BACKGROUND: Molecular and antigen point-of-care tests (POCTs) have augmented our ability to rapidly identify and manage SARS-CoV-2 infection. However, their clinical performance varies among individual studies. OBJECTIVES: The evaluation of the performance of molecular and antigen-based POCTs in confirmed, suspected, or probable COVID-19 cases compared with that of laboratory-based RT-PCR in real-life settings. DATA SOURCES: MEDLINE/PubMed, Scopus, Embase, Web of Science, Cochrane Library, Cochrane COVID-19 study register, and COVID-19 Living Evidence Database from the University of Bern. STUDY ELIGIBILITY CRITERIA: Peer-reviewed or preprint observational studies or randomized controlled trials that evaluated any type of commercially available antigen and/or molecular POCTs for SARS-CoV-2, including multiplex PCR panels, approved by the United States Food and Drug Administration, with Emergency Use Authorization, and/or marked with Conformitè Europëenne from European Commission/European Union. PARTICIPANTS: Close contacts and/or patients with symptomatic and/or asymptomatic confirmed, suspected, or probable COVID-19 infection of any age. TEST/S: Molecular and/or antigen-based SARS-CoV-2 POCTs. REFERENCE STANDARD: Laboratory-based SARS-CoV-2 RT-PCR. ASSESSMENT OF RISK OF BIAS: Eligible studies were subjected to quality-control and risk-of-bias assessment using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. METHODS OF DATA SYNTHESIS: Summary sensitivities and specificities with their 95% CIs were estimated using a bivariate model. Subgroup analysis was performed when at least three studies informed the outcome. RESULTS: A total of 123 eligible publications (97 and 26 studies assessing antigen-based and molecular POCTs, respectively) were retrieved from 4674 initial records. The pooled sensitivity and specificity for 13 molecular-based POCTs were 92.8% (95% CI, 88.9-95.4%) and 97.6% (95% CI, 96.6-98.3%), respectively. The sensitivity of antigen-based POCTs pooled from 138 individual evaluations was considerably lower than that of molecular POCTs; the pooled sensitivity and specificity rates were 70.6% (95% CI, 67.2-73.8%) and 98.9% (95% CI, 98.5-99.2%), respectively. DISCUSSION: Further studies are needed to evaluate the performance of molecular and antigen-based POCTs in underrepresented patient subgroups and different respiratory samples.

An updated review of SARS-CoV-2 detection methods in the context of a novel coronavirus pandemic.

The World Health Organization has reported approximately 430 million confirmed cases of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), worldwide, including nearly 6 million deaths, since its initial appearance in China in 2019. While the number of diagnosed cases continues to increase, the need for technologies that can accurately and rapidly detect SARS-CoV-2 virus infection at early phases continues to grow, and the Federal Drug Administration (FDA) has licensed emergency use authorizations (EUAs) for virtually hundreds of diagnostic tests based on nucleic acid molecules and antigen-antibody serology assays. Among them, the quantitative real-time reverse transcription PCR (qRT-PCR) assay is considered the gold standard for early phase virus detection. Unfortunately, qRT-PCR still suffers from disadvantages such as the complex test process and the occurrence of false negatives; therefore, new nucleic acid detection devices and serological testing technologies are being developed. However, because of the emergence of strongly infectious mutants of the new coronavirus, such as Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron (B.1.1.529), the need for the specific detection of mutant strains is also increasing. Therefore, this article reviews nucleic acid- and antigen-antibody-based serological assays, and compares the performance of some of the most recent FDA-approved and literature-reported assays and associated kits for the specific testing of new coronavirus variants.

Analytical performance of four rapid molecular testing for SARS-CoV-2

Various reagents and equipment for testing SARS-CoV-2 infections have been developed, particularly rapid molecular tests based on polymerase chain reaction (PCR).We evaluated the analytical performance of four rapid molecular tests for SARS-CoV-2. We used 56 nasopharyngeal swabs from patients with confirmed SARS-CoV-2 infection;36 diagnosed as positive by the Ampdirect™ 2019-nCoV Detection Kit (Shimadzu assay) were considered as true-positive samples.The sensitivity of Cobas® Liat SARS-CoV-2 and Flu A/B (Cobas) was the highest among the four molecular test kits. The limit of detection was 1.49 × 10−2 copies/µL (95% confidence interval [CI]: 1.46×10−2−1.51 × 10−2 copies/µL) for Cobas;1.43 × 10−1 copies/µL (95% CI: 8.01×10−3−2.78 × 10−1 copies/µL) for Xpert® Xpress SARS-CoV-2 test (Xpert);2.00 × 10−1 copies/µL (95% CI: 1.95×10−1-2.05 × 10−1 copies/µL) for FilmArray Respiratory Panel v2.1 (FilmArray);and 3.33 × 10 copies/µL (95% CI: 1.93 × 10–4.72×10 copies/µL) for Smart Gene® SARS-CoV-2 (Smart gene). Cobas also had a high sensitivity (100%) compared with Shimadzu assay. The sensitivities of Xpert, FilmArray, and Smart Gene were 97.2%, 97.2%, and 75.0%, respectively. The specificity of all tests was 100%.In conclusion, the four rapid SARS-CoV-2 molecular test kits have high specificity and sensitivity for detecting SARS-CoV-2. As they are easy to use, they could be a useful method for detecting SARS-CoV-2.

Severe Acute Respiratory Syndrome Coronavirus 2 Diagnostic Tests for Border Screening During the Very Early Phase of Coronavirus Disease 2019 Pandemic: A Systematic Review and Meta-Analysis.

Diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during border screening among returning residents and prioritized travelers during the early phase of a pandemic can reduce the risk of importation and transmission in the community. This study aimed to compare the accuracy of various SARS-CoV-2 diagnostics and assess their potential utility as border screening for infection and immunity. Systematic literature searches were conducted in six electronic databases for studies reporting SARS-CoV-2 diagnostics (up to April 30, 2020). Meta-analysis and methodological assessment were conducted for all included studies. The performance of the diagnostic tests was evaluated with pooled sensitivity, specificity, and their respective 95% confidence intervals. A total of 5,416 unique studies were identified and 95 studies (at least 29,785 patients/samples) were included. Nucleic acid amplification tests (NAAT) consistently outperformed all other diagnostic methods regardless of the selected viral genes with a pooled sensitivity of 98% and a pooled specificity of 99%. Point-of-care (POC) serology tests had moderately high pooled sensitivity (69%), albeit lower than laboratory-based serology tests (89%), but both had high pooled specificity (96-98%). Serology tests were more sensitive for sampling collected at ≥ 7 days than ≤ 7 days from the disease symptoms onset. POC NAAT and POC serology tests are suitable for detecting infection and immunity against the virus, respectively as border screening. Independent validation in each country is highly encouraged with the preferred choice of diagnostic tool/s.

A machine learning study of COVID-19 serology and molecular tests and predictions.

Serology and molecular tests are the two most commonly used methods for rapid COVID-19 infection testing. The two types of tests have different mechanisms to detect infection, by measuring the presence of viral SARS-CoV-2 RNA (molecular test) or detecting the presence of antibodies triggered by the SARS-CoV-2 virus (serology test). A handful of studies have shown that symptoms, combined with demographic and/or diagnosis features, can be helpful for the prediction of COVID-19 test outcomes. However, due to nature of the test, serology and molecular tests vary significantly. There is no existing study on the correlation between serology and molecular tests, and what type of symptoms are the key factors indicating the COVID-19 positive tests. In this study, we propose a machine learning based approach to study serology and molecular tests, and use features to predict test outcomes. A total of 2,467 donors, each tested using one or multiple types of COVID-19 tests, are collected as our testbed. By cross checking test types and results, we study correlation between serology and molecular tests. For test outcome prediction, we label 2,467 donors as positive or negative, by using their serology or molecular test results, and create symptom features to represent each donor for learning. Because COVID-19 produces a wide range of symptoms and the data collection process is essentially error prone, we group similar symptoms into bins. This decreases the feature space and sparsity. Using binned symptoms, combined with demographic features, we train five classification algorithms to predict COVID-19 test results. Experiments show that XGBoost achieves the best performance with 76.85% accuracy and 81.4% AUC scores, demonstrating that symptoms are indeed helpful for predicting COVID-19 test outcomes. Our study investigates the relationship between serology and molecular tests, identifies meaningful symptom features associated with COVID-19 infection, and also provides a way for rapid screening and cost effective detection of COVID-19 infection.

Update of Guidelines for Laboratory Diagnosis of COVID-19 in Korea.

Korean Society for Laboratory Medicine and the Korea Disease Prevention and Control Agency have announced guidelines for diagnosing coronavirus disease (COVID-19) in clinical laboratories in Korea. With the ongoing pandemic, we propose an update of the previous guidelines based on new scientific data. This update includes recommendations for tests that were not included in the previous guidelines, including the rapid molecular test, antigen test, antibody test, and self-collected specimens, and a revision of the previous recommendations. This update will aid clinical laboratories in performing laboratory tests for diagnosing COVID-19.

FDA authorized molecular point-of-care SARS-CoV-2 tests: A critical review on principles, systems and clinical performances.

Since the start of the COVID-19 pandemic, 10 manufacturers of molecular tests for SARS-CoV-2 have received Emergency Use Authorizations from the U.S. Food and Drug Administration for point-of-care or over the counter use. In this review, the working principle of these tests is described as well as the relevant characteristics (e.g. time-to-result and specimen type). The analytical (e.g. analytical sensitivity) and clinical performance (positive and negative percent agreement) and useability characteristics (e.g. cost, reusability and throughput) of these tests are compared and critically reviewed. Also details for relevant respiratory multiplex assays of these 10 manufacturers are discussed. Critical review of scientific literature on these authorized tests revealed that for many of these tests publications are almost or completely absent, with the exception of two systems. The Xpert Xpress has been thoroughly investigated and good performance has been reported, whereas ID NOW is also well-represented in literature, but has relatively low sensitivity.

Comparative Evaluation of Rapid Isothermal Amplification and Antigen Assays for Screening Testing of SARS-CoV-2.

Human transmission of SARS-CoV-2 and emergent variants of concern continue to occur globally, despite mass vaccination campaigns. Public health strategies to reduce virus spread should therefore rely, in part, on frequent screening with rapid, inexpensive, and sensitive tests. We evaluated two digitally integrated rapid tests and assessed their performance using stored nasal swab specimens collected from individuals with or without COVID-19. An isothermal amplification assay combined with a lateral flow test had a limit of detection of 10 RNA copies per reaction, and a positive percent agreement (PPA)/negative percent agreement (NPA) during the asymptomatic and symptomatic phases of 100%/100% and 95.83/100%, respectively. Comparatively, an antigen-based lateral flow test had a limit of detection of 30,000 copies and a PPA/NPA during the asymptomatic and symptomatic phases of 82.86%/98.68% and 91.67/100%, respectively. Both the isothermal amplification and antigen-based lateral flow tests had optimized detection of SARS-CoV-2 during the peak period of transmission; however, the antigen-based test had reduced sensitivity in clinical samples with qPCR Ct values greater than 29.8. Low-cost, high-throughput screening enabled by isothermal amplification or antigen-based techniques have value for outbreak control.

COVID-19 and schools: what is the risk of contagion? Results of a rapid-antigen-test-based screening campaign in Florence, Italy.

INTRODUCTION: In the coronavirus disease 2019 era, debate around the risk of contagion in school is intense in Italy. The Department of Welfare and Health of Florence promoted a screening campaign with rapid antigen tests for all students and school personnel. The aim of this study was to assess the circulation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in the school setting by means of mass screening in every primary and middle school in Florence. METHODS: All students and school personnel at primary and middle schools in Florence were asked to take part. The campaign started on 16 November 2020 and was completed on 12 February 2021. If a subject had a positive result on rapid antigen testing, a molecular test was performed to confirm the result. RESULTS: In total, 18,414 subjects were tested: 15,233 students (82.7%) and 3181 school personnel (17.3%). The rapid antigen test gave a positive result in 27 cases (0.15%). Of these, only 14 tests were confirmed to be positive on molecular testing. These results show a very low number of cases of SARS-CoV-2 among the study subjects (0.08%). CONCLUSIONS: These results show that the spread of SARS-CoV-2 in the school setting was low in Florence during the screening period.

Optimization and Clinical Validation of Colorimetric Reverse Transcription Loop-Mediated Isothermal Amplification, a Fast, Highly Sensitive and Specific COVID-19 Molecular Diagnostic Tool That Is Robust to Detect SARS-CoV-2 Variants of Concern.

The coronavirus disease 2019 (COVID-19) pandemic unfolded due to the widespread severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission reinforced the urgent need for affordable molecular diagnostic alternative methods for massive testing screening. We present the clinical validation of a pH-dependent colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) for SARS-CoV-2 detection. The method revealed a limit of detection of 19.3 ± 2.7 viral genomic copies/µL when using RNA extracted samples obtained from nasopharyngeal swabs collected in guanidine-containing viral transport medium. Typical RT-LAMP reactions were performed at 65°C for 30 min. When compared to reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR), up to cycle-threshold (Ct) value 32, RT-LAMP presented 98% [95% confidence interval (CI) = 95.3-99.5%] sensitivity and 100% (95% CI = 94.5-100%) specificity for SARS-CoV-2 RNA detection targeting E and N genes. No cross-reactivity was detected when testing other non-SARS-CoV virus, confirming high specificity. The test is compatible with primary RNA extraction-free samples. We also demonstrated that colorimetric RT-LAMP can detect SARS-CoV-2 variants of concern and variants of interest, such as variants occurring in Brazil named gamma (P.1), zeta (P.2), delta (B.1.617.2), B.1.1.374, and B.1.1.371. The method meets point-of-care requirements and can be deployed in the field for high-throughput COVID-19 testing campaigns, especially in countries where COVID-19 testing efforts are far from ideal to tackle the pandemics. Although RT-qPCR is considered the gold standard for SARS-CoV-2 RNA detection, it requires expensive equipment, infrastructure, and highly trained personnel. In contrast, RT-LAMP emerges as an affordable, inexpensive, and simple alternative for SARS-CoV-2 molecular detection that can be applied to massive COVID-19 testing campaigns and save lives.

Prospective evaluation of specimen pooling strategy for detection of SARS-CoV-2 using pools of five and six specimens.

The increased demand for SARS-CoV-2 molecular testing during the COVID-19 pandemic resulted in shortage of reagents and consumables. Pooling of specimens could be an alternative strategy to overcome these problems. Initial evaluation of the pooling strategy was performed using known positive specimens, previously tested individually, and their respective pools of plus four (5X), five (6X) and nine (10X) known negative specimens. Subsequently, 35 positive 5X and 35 positive 6X pools containing only one positive specimen per pool were analyzed prospectively regarding the difference in Ct values in pooled versus individual specimens. When the number of samples in the pool were five or six, the average deviation of Ct differences was < 1; therefore, this strategy was followed in the prospective study. Significant difference in Ct values was observed in positive specimens when tested individually and in 5X pools (p = 0.006), while the difference was not significant when positive specimens were tested individually and in 6X pools (p = 0.07). The difference in Ct values was not significant between the 5X and 6X pools. Testing in pools of five or six specimens is a reliable option for SARS-CoV-2 RNA detection when mass testing is needed.

Review of Current COVID-19 Diagnostics and Opportunities for Further Development.

Diagnostic testing plays a critical role in addressing the coronavirus disease 2019 (COVID-19) pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Rapid and accurate diagnostic tests are imperative for identifying and managing infected individuals, contact tracing, epidemiologic characterization, and public health decision making. Laboratory testing may be performed based on symptomatic presentation or for screening of asymptomatic people. Confirmation of SARS-CoV-2 infection is typically by nucleic acid amplification tests (NAAT), which requires specialized equipment and training and may be particularly challenging in resource-limited settings. NAAT may give false-negative results due to timing of sample collection relative to infection, improper sampling of respiratory specimens, inadequate preservation of samples, and technical limitations; false-positives may occur due to technical errors, particularly contamination during the manual real-time polymerase chain reaction (RT-PCR) process. Thus, clinical presentation, contact history and contemporary phyloepidemiology must be considered when interpreting results. Several sample-to-answer platforms, including high-throughput systems and Point of Care (PoC) assays, have been developed to increase testing capacity and decrease technical errors. Alternatives to RT-PCR assay, such as other RNA detection methods and antigen tests may be appropriate for certain situations, such as resource-limited settings. While sequencing is important to monitor on-going evolution of the SARS-CoV-2 genome, antibody assays are useful for epidemiologic purposes. The ever-expanding assortment of tests, with varying clinical utility, performance requirements, and limitations, merits comparative evaluation. We herein provide a comprehensive review of currently available COVID-19 diagnostics, exploring their pros and cons as well as appropriate indications. Strategies to further optimize safety, speed, and ease of SARS-CoV-2 testing without compromising accuracy are suggested. Access to scalable diagnostic tools and continued technologic advances, including machine learning and smartphone integration, will facilitate control of the current pandemic as well as preparedness for the next one.

Social Restrictions versus Testing Campaigns in the COVID-19 Crisis: A Predictive Model Based on the Spanish Case.

The global COVID-19 spread has forced countries to implement non-pharmacological interventions (NPI) (i.e., mobility restrictions and testing campaigns) to preserve health systems. Spain is one of the most severely impacted countries, both clinically and economically. In an effort to support policy decision-making, we aimed to assess the impacts of different NPI on COVID-19 epidemiology, healthcare costs and Gross Domestic Product (GDP). A modified Susceptible-Exposed-Infectious-Removed epidemiological model was created to simulate the pandemic evolution. Its output was used to populate an economic model to quantify healthcare costs and GDP variation through a regression model which correlates NPI and GDP change from 42 countries. Thirteen scenarios combining different NPI were consecutively simulated in the epidemiological and economic models. Both increased testing and stringency could reduce cases, hospitalizations and deaths. While policies based on increased testing rates lead to higher healthcare costs, increased stringency is correlated with greater GDP declines, with differences of up to 4.4% points. Increased test sensitivity may lead to a reduction of cases, hospitalizations and deaths and to the implementation of pooling techniques that can increase throughput testing capacity. Alternative strategies to control COVID-19 spread entail differing economic outcomes. Decision-makers may utilize this tool to identify the most suitable strategy considering epidemiological and economic outcomes.

Development of General Methods for Detection of Virus by Engineering Fluorescent Silver Nanoclusters.

Viruses have caused significant damage to the world. Effective detection is required to relieve the impact of viral infections. A biomolecule can be used as a template such as deoxyribonucleic acid (DNA), peptide, or protein, for the growth of silver nanoclusters (AgNCs) and for recognizing a virus. Both the AgNCs and the recognition elements are tunable, which is promising for the analysis of new viruses. Considering that a new virus such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) urgently requires a facile sensing strategy, various virus detection strategies based on AgNCs including fluorescence enhancement, color change, quenching, and recovery are summarized. Particular emphasis is placed on the molecular analysis of viruses using DNA stabilized AgNCs (DNA-AgNCs), which detect the virus's genetic material. The more widespread applications of AgNCs for general virus detection are also discussed. Further development of these technologies may address the challenge for facile detection of SARS-CoV-2.

Variability of cycle threshold values in an external quality assessment scheme for detection of the SARS-CoV-2 virus genome by RT-PCR.

OBJECTIVES: The qualitative results of SARS-CoV-2 specific real-time reverse transcription (RT) PCR are used for initial diagnosis and follow-up of Covid-19 patients and asymptomatic virus carriers. However, clinical decision-making and health management policies often are based additionally on cycle threshold (Ct) values (i.e., quantitative results) to guide patient care, segregation and discharge management of individuals testing positive. Therefore, an analysis of inter-protocol variability is needed to assess the comparability of the quantitative results. METHODS: Ct values reported in a SARS-CoV-2 virus genome detection external quality assessment challenge were analyzed. Three positive and two negative samples were distributed to participating test laboratories. Qualitative results (positive/negative) and quantitative results (Ct values) were assessed. RESULTS: A total of 66 laboratories participated, contributing results from 101 distinct test systems and reporting Ct values for a total of 92 different protocols. In all three positive samples, the means of the Ct values for the E-, N-, S-, RdRp-, and ORF1ab-genes varied by less than two cycles. However, 7.7% of reported results deviated by more than ±4.0 (maximum 18.0) cycles from the respective individual means. These larger deviations appear to be systematic errors. CONCLUSIONS: In an attempt to use PCR diagnostics beyond the identification of infected individuals, laboratories are frequently requested to report Ct values along with a qualitative result. This study highlights the limitations of interpreting Ct values from the various SARS-CoV genome detection protocols and suggests that standardization is necessary in the reporting of Ct values with respect to the target gene.

Mass screening vs lockdown vs combination of both to control COVID-19: A systematic review.

Coronavirus disease 2019 (COVID-19) is a global pandemic. Non-pharmacological interventions, such as lockdown and mass testing, remain as the mainstay of control measures for the outbreak. We aim to evaluate the effectiveness of mass testing, lockdown, or a combination of both to control COVID-19 pandemic. A systematic search on 11 major databases was conducted on June 8, 2020. This review is registered in Prospero (CRD420201 90546). We included primary studies written in English which investigate mass screening, lockdown, or a combination of both to control and/or mitigate the COVID-19 pandemic. There are four important outcomes as selected by WHO experts for their decision- making process: incident cases, onward transmission, mortality, and resource use. Among 623 studies, only 14 studies met our criteria. Four observational studies were rated as strong evidence and ten modelling studies were rated as moderate evidence. Based on one modelling study, mass testing reduced the total infected people compared to no mass testing. For lockdown, ten studies consistently showed that it successfully reduced the incidence, onward transmission, and mortality rate of COVID-19. A limited evidence showed that a combination of lockdown and mass screening resulted in a greater reduction of incidence and mortality rate compared to lockdown only. However, there is not enough evidence on the effectiveness of mass testing only.

COVID-19: Understanding Testing.

Occupational health nurses need to understand tests for COVID-19 infection and antibodies, how to interpret results, and where to find credible information and resources.

An Italian Neurorehabilitation Hospital Facing the SARS-CoV-2 Pandemic: Data From 1207 Patients and Workers.

Objective: The aim of the present observational study is to report on the data from a large sample of inpatients, clinical staff and other workers at an Italian neurorehabilitation hospital dealing with SARS-CoV-2 infections, in order to analyze how it might have affected the management and the effectiveness of neurorehabilitation. Methods: The data on infection monitoring, obtained by 2,192 swabs, were reported and compared among 253 patients, 722 clinical professionals and 232 other hospital workers. The number of admissions and neurorehabilitation sessions performed in the period from March-May 2020 was compared with those of the same period in 2019. Results: Four patients and three clinical professionals were positive for COVID-19 infection. Six out of these seven people were from the same ward. Several measures were taken to handle the infection, putting in place many restrictions, with a significant reduction in new admissions to the hospital (p < 0.001). However, neither the amount of neurorehabilitation for inpatients (p = 0.681) nor the effectiveness of treatments (p = 0.464) were reduced when compared to the data from 2019. Conclusions: Our data show that the number of infections was contained in our hospital, probably thanks to the protocols adopted for reducing contagion and the environmental features of our wards. This allowed inpatients to continue to safely spend more than 3 hours per day in neurorehabilitation, effectively improving their independence in the activities of daily living.

Saliva as an Alternative Specimen for Molecular COVID-19 Testing in Community Settings and Population-Based Screening.

PURPOSE: With the easing of restriction measures, repeated community-based sampling for tracking new COVID-19 infections is anticipated for the next 6 to 12 months. A non-invasive, self-collected specimen like saliva will be useful for such public health surveillance. Investigations on the use of saliva for SARS-CoV-2 RT-PCR have largely been among COVID-19 in-pa\tients and symptomatic ambulatory patients with limited work in a community-based screening setting. This study was carried out to address this paucity of data and reported discrepancies in diagnostic accuracy for saliva samples. PATIENTS AND METHODS: From 29th June to 14th July 2020, adults presenting for COVID-19 testing at a community-based screening facility in Dubai, United Arab Emirates were recruited. Clinical data, nasopharyngeal swab in universal transport media and drooling saliva in sterile containers were obtained. Reverse transcriptase PCR amplification of SARS-CoV-2 RdRp and N genes was used to detect the presence of the SARS-CoV-2 virus. RESULTS: Of the 401 participants, 35 (8.7%) had viral detection in at least one specimen type and the majority (n=20/35; 57.1%) were asymptomatic. Both swab and saliva were positive in 19 (54.2%) patients, while 7 (20.0%) patients had swab positive/saliva negative results. There were 9 (25.7%) patients with saliva positive/swab negative result and this included 5 asymptomatic COVID-19 patients undergoing repeat screening. Using the swab as the reference gold standard, the sensitivity and specificity of saliva were 73.1% (95% CI 52.2-88.4%) and 97.6% (95% CI 95.5-98.9%) while the positive and negative predictive values were 67.9% (95% CI 51.5-80.8%) and 98.1% (95% CI 96.5-99.0%), respectively. CONCLUSION: The findings suggest good diagnostic accuracy for saliva and feasibility of utilization of specimen without transport media for SARS-CoV-2 RT-PCR. Saliva represents a potential specimen of choice in community settings and population-based screening.