SciBeh-Topic-Visualization

screen, test, pool, saliva, surveillance

Topic 29

screen test pool saliva surveillance diagnostic immunoassay serology fda rapid point asymptomatic free aggressive antigen

Millions of Rapid COVID-19 Antigen Tests May Help Fill the Testing Gap
May 7, 2020 · · Original resource · blog

The assays may not detect all cases, but they are cheap and could be used at home
covid-19
usa
testing
cost
diagnosis
speed
detection
demand
screen, test, pool, saliva, surveillance
herd, immunity, far, hope, know
Efficient high throughput SARS-CoV-2 testing to detect asymptomatic carriers

The COVID-19 pandemic is rapidly spreading throughout the world. Recent reports suggest that 10-30% of SARS-CoV-2 infected patients are asymptomatic. Other studies report that some subjects have significant viral shedding prior to symptom onset. Since both asymptomatic and pre-symptomatic subjects can spread the disease, identifying such individuals is critical for effective control of the SARS-CoV-2 pandemic. Therefore, there is an urgent need to increase diagnostic testing capabilities in order to also screen asymptomatic carriers. In fact, such tests will be routinely required until a vaccine is developed. Yet, a major bottleneck of managing the COVID-19 pandemic in many countries is diagnostic testing, due to limited laboratory capabilities as well as limited access to genome-extraction and Polymerase Chain Reaction (PCR) reagents. We developed P-BEST - a method for Pooling-Based Efficient SARS-CoV-2 Testing, using a non-adaptive group-testing approach, which significantly reduces the number of tests required to identify all positive subjects within a large set of samples. Instead of testing each sample separately, samples are pooled into groups and each pool is tested for SARS-CoV-2 using the standard clinically approved PCR-based diagnostic assay. Each sample is part of multiple pools, using a combinatorial pooling strategy based on compressed sensing designed for maximizing the ability to identify all positive individuals. We evaluated P-BEST using leftover samples that were previously clinically tested for COVID-19. In our current proof-of-concept study we pooled 384 patient samples into 48 pools providing an 8-fold increase in testing efficiency. Five sets of 384 samples, containing 1-5 positive carriers were screened and all positive carriers in each set were correctly identified. P-BEST provides an efficient and easy-to-implement solution for increasing testing capacity that will work with any clinically approved genome-extraction and PCR-based diagnostic methodologies.
covid-19
vaccine
testing
symptom
detection
asymptomatic
diagnostics
laboratory
screen, test, pool, saliva, surveillance
protein, spike, neutralize, ace2, design
Pooling of samples for testing for SARS-CoV-2 in asymptomatic people

The ongoing coronavirus disease 2019 (COVID-19) pandemic is a substantial challenge for health-care systems and their infrastructure. RT-PCR-based diagnostic confirmation of infected individuals is crucial to contain viral spread because infection can be asymptomatic despite high viral loads. Sufficient molecular diagnostic capacity is important for public health interventions such as case detection and isolation, including for health-care professionals.1Koo JR Cook AR Park M et al.Interventions to mitigate early spread of SARS-CoV-2 in Singapore: a modelling study.Lancet Infect Dis. 2020; (published online March 23.)https://doi.org/10.1016/S1473-3099(20)30162-6Google ScholarProtocols for RNA RT-PCR testing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became available early in the pandemic, yet the infrastructure of testing laboratories is stretched and in some areas it is overwhelmed.2Corman VM Landt O Kaiser M et al.Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR.Euro Surveill. 2020; 252000045Google Scholar We propose a testing strategy that is easy to implement and can expand the capacity of the available laboratory infrastructure and test kits when large numbers of asymptomatic people need to be screened. We introduced the pooling of samples before RT-PCR amplification, and only in the case of positive pool test results is work-up of individual samples initiated, thus potentially substantially reducing the number of tests needed.
covid-19
infection
public health
transmission
testing
health system
healthcare
symptom
intervention
viral load
detection
infrastructure
asymptomatic
the lancet
sample
sars, respiratory, clinical, cov, syndrome
screen, test, pool, saliva, surveillance
SalivaDirect: Simple and sensitive molecular diagnostic test for SARS-CoV-2 surveillance

Current bottlenecks for improving accessibility and scalability of SARS-CoV-2 testing include diagnostic assay costs, complexity, and supply chain shortages. To resolve these issues, we developed SalivaDirect. The critical component of our approach is to use saliva instead of respiratory swabs, which enables non-invasive frequent sampling and reduces the need for trained healthcare professionals during collection. Furthermore, we simplified our diagnostic test by (1) not requiring nucleic acid preservatives at sample collection, (2) replacing nucleic acid extraction with a simple proteinase K and heat treatment step, and (3) testing specimens with a dualplex quantitative reverse transcription PCR (RT-qPCR) assay. We validated SalivaDirect with reagents and instruments from multiple vendors to minimize the risk for supply chain issues. Regardless of our tested combination of reagents and instruments from different vendors, we found that SalivaDirect is highly sensitive with a limit of detection of 6-12 SARS-CoV-2 copies/μL. When comparing paired nasopharyngeal swabs and saliva specimens using the authorized ThermoFisher Scientific TaqPath COVID-19 combo kit and our SalivaDirect protocol, we found high agreement in testing outcomes (>94%). Being flexible and inexpensive ($1.29-$4.37/sample), SalivaDirect is a viable and accessible option to help alleviate SARS-CoV-2 testing demands. We submitted SalivaDirect as a laboratory developed test to the US Food and Drug Administration for Emergency Use Authorization on July 14th, 2020, and current details can be found on our website (covidtrackerct.com/about-salivadirect/).
covid-19
development
comparison
testing
expertise
cost
swab test
scalability
accessibility
sampling
surveillance
diagnostics
screen, test, pool, saliva, surveillance
protein, spike, neutralize, ace2, design
Serology testing in the COVID-19 pandemic response

The collapse of global cooperation and a failure of international solidarity have led to many low-income and middle-income countries being denied access to molecular diagnostics in the COVID-19 pandemic response. Yet the scarcity of knowledge on the dynamics of the immune response to infection has led to hesitation on recommending the use of rapid immunodiagnostic tests, even though rapid serology tests are commercially available and scalable. On the basis of our knowledge and understanding of viral infectivity and host response, we urge countries without the capacity to do molecular testing at scale to research the use of serology tests to triage symptomatic patients in community settings, to test contacts of confirmed cases, and in situational analysis and surveillance. The WHO R&D Blue Print expert group identified eight priorities for research and development, of which the highest is to mobilise research on rapid point-of-care diagnostics for use at the community level. This research should inform control programmes of the required performance and utility of rapid serology tests, which, when applied specifically for appropriate public health measures to then be put in place, can make a huge difference.
covid-19
public health
community
immune response
serology
surveillance
tackle, european, fund, database, indonesia
screen, test, pool, saliva, surveillance
Coronavirus (COVID-19) Update: FDA Authorizes First Point-of-Care Antibody Test for COVID-19
Sept. 23, 2020 · · Original resource · news

Today, the U.S. Food and Drug Administration issued an emergency use authorization (EUA) for the first serology (antibody) point-of-care (POC) test for COVID-19. The Assure COVID-19 IgG/IgM Rapid Test Device was first authorized for emergency use by certain labs in July 2020 to help identify individuals with antibodies to SARS-CoV-2, indicating recent or prior COVID-19 infection. Today, that EUA is being reissued to authorize the test for POC use using fingerstick blood samples. This authorization means that fingerstick blood samples can now be tested in POC settings like doctor’s offices, hospitals, urgent care centers and emergency rooms rather than having to be sent to a central lab for testing.
covid-19
protection
strategy
fda
public health response
serology
vaccine, trial, approve, drug, healthy
screen, test, pool, saliva, surveillance
Rapid point-of-care testing for SARS-CoV-2 in a community screening setting shows low sensitivity

ObjectiveWith the current SARS-CoV2 outbreak, countless tests need to be performed on potential symptomatic individuals, contacts and travellers. The gold standard is a quantitative polymerase chain reaction (qPCR)–based system taking several hours to confirm positivity. For effective public health containment measures, this time span is too long. We therefore evaluated a rapid test in a high-prevalence community setting.Study designThirty-nine randomly selected individuals at a COVID-19 screening centre were simultaneously tested via qPCR and a rapid test. Ten previously diagnosed individuals with known SARS-CoV-2 infection were also analysed.MethodsThe evaluated rapid test is an IgG/IgM–based test for SARS-CoV-2 with a time to result of 20 min. Two drops of blood are needed for the test performance.ResultsOf 49 individuals, 22 tested positive by repeated qPCR. In contrast, the rapid test detected only eight of those positive correctly (sensitivity: 36.4%). Of the 27 qPCR-negative individuals, 24 were detected correctly (specificity: 88.9%).ConclusionGiven the low sensitivity, we recommend not to rely on an antibody-based rapid test for public health measures such as community screenings.
covid-19
public health
testing
community
screening
outbreak
study
sensitivity
rapid
test
sars, respiratory, clinical, cov, syndrome
screen, test, pool, saliva, surveillance
Evaluation of antibody testing for SARS-Cov-2 using ELISA and lateral flow immunoassays

Background: The SARS-CoV-2 pandemic caused >1 million infections during January-March 2020. There is an urgent need for robust antibody detection approaches to support diagnostics, vaccine development, safe individual release from quarantine and population lock-down exit strategies. The early promise of lateral flow immunoassay (LFIA) devices has been questioned following concerns about sensitivity and specificity. Methods: We used a panel of plasma samples designated SARS-CoV-2 positive (from SARS-CoV-2 RT-PCR-positive individuals; n=40) and negative (samples banked in the UK prior to December-2019 (n=142)). We tested plasma for SARS-Cov-2 IgM and IgG antibodies by ELISA and using nine different commercially available LFIA devices. Results: ELISA detected SARS-CoV-2 IgM or IgG in 34/40 individuals with an RT-PCR-confirmed diagnosis of SARS-CoV-2 infection (sensitivity 85%, 95%CI 70-94%), vs 0/50 pre-pandemic controls (specificity 100% [95%CI 93-100%]). IgG levels were detected in 31/31 RT-PCR-positive individuals tested ≥10 days after symptom onset (sensitivity 100%, 95%CI 89-100%). IgG titres rose during the 3 weeks post symptom onset and began to fall by 8 weeks, but remained above the detection threshold. Point estimates for the sensitivity of LFIA devices ranged from 55-70% versus RT-PCR and 65-85% versus ELISA, with specificity 95-100% and 93-100% respectively. Within the limits of the study size, the performance of most LFIA devices was similar. Conclusions: The performance of current LFIA devices is inadequate for most individual patient applications. ELISA can be calibrated to be specific for detecting and quantifying SARS-CoV-2 IgM and IgG and is highly sensitive for IgG from 10 days following symptoms onset.
covid-19
vaccine
lockdown
loosening restrictions
detection
study
antibodies
diagnostics
exit
lockdown cessetion
quarantine
cell, antibody, immune, cov-2-specific, epitope
screen, test, pool, saliva, surveillance
COVID-19: the case for health-care worker screening to prevent hospital transmission

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has placed unprecedented strain on health-care services worldwide, leading to more than 100 000 deaths worldwide, as of April 15, 2020.1WHOCoronavirus disease (COVID-19) situation report – 84.https://www.who.int/emergencies/diseases/novel-coronavirus-2019Date: April 13, 2020Date accessed: April 14, 2020Google ScholarMost testing for SARS-CoV-2 aims to identify current infection by molecular detection of the SARS-CoV-2 antigen; this involves a RT-PCR of viral RNA in fluid, typically obtained from the nasopharynx or oropharynx.2Beeching NJ Fletcher TE Beadsworth MBJ Covid-19: testing times.BMJ. 2020; 369m1403Google ScholarThe global approach to SARS-CoV-2 testing has been non-uniform. In South Korea, testing has been extensive, with emphasis on identifying individuals with respiratory illness, and tracing and testing any contacts. Other countries (eg, Spain) initially limited testing to individuals with severe symptoms or those at high risk of developing them.Here we outline the case for mass testing of both symptomatic and asymptomatic health-care workers (HCWs) to: (1) mitigate workforce depletion by unnecessary quarantine; (2) reduce spread in atypical, mild, or asymptomatic cases; and (3) protect the health-care workforce.
covid-19
transmission
testing
healthcare
prevention
screening
asymptomatic
symptomatic
quarentine
medical staff
hospital
sars, respiratory, clinical, cov, syndrome
screen, test, pool, saliva, surveillance
COVID-19 diagnostics in context

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the need for different types of diagnostics, comparative validation of new tests, faster approval by federal agencies, and rapid production of test kits to meet global demands. In this Perspective, we discuss the utility and challenges of current diagnostics for COVID-19.
covid-19
immunity
testing
citation
sensitivity
time
sars, respiratory, clinical, cov, syndrome
screen, test, pool, saliva, surveillance