Unexplained longitudinal variability in COVID-19 antibody status by Lateral Flow Immuno-Antibody testing

BackgroundCOVID-19 antibody testing allows population studies to classify participants by previous SARS-CoV-2 infection status. Home lateral flow immune-antibody testing devices offer a very convenient way of doing this, but relatively little is known about how measurement and antibody variability will affect consistency in results over time. We examined consistency by looking at the outcome of two tests three months apart while COVID-19 infection rates were low (summer 2020 in the UK).MethodsThe KCL-Coronavirus Health and Experiences in Colleagues at King’s is an occupational cohort of staff and postgraduate research students. Lateral flow immune-antibody testing kits were sent to participant’s homes in late June 2020 and late September 2020. Participants also completed regular surveys that included asking about COVID-19 symptoms and whether they thought they had been infected.ResultsWe studied 1489 participants returned valid results in both June and September (59% of those sent kits). Lateral flow immune-antibody test was positive for 7.2% in June and 5.9% in September, with 3.9% positive in both. Being more symptomatic or suspecting infection increased the probability of ever being positive. Of those positive in June, 46% (49/107) were negative in September (seroreversion), and this was similar regardless of symptom characteristics, suspicion, and timing of possible infection. A possible outlier was those aged over 55 years, where only 3 of 13 (23%) had seroreversion.DiscussionThese results do not follow the pattern reported from studies specifically designed to monitor seropositivity, which have found greater consistency over time and the influence of presence, timing and severity of symptoms on seroreversion. We suggest several factors that may have contributed to this difference: our low bar in defining initial seropositivity (single test); a non-quantitative test known to have relatively low sensitivity; participants carrying out testing. We would encourage other studies to use these real-world performance characteristics alongside those from laboratory studies to plan and analyse any antibody testing.

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Indicators of COVID-19 status in a cohort study of university staff and post-graduate research students, including results from home antibody testing

10.1101/2020.12.07.20245183 ◽

2020 ◽

Author(s):

Katrina A. S. Davis ◽

Ewan Carr ◽

Daniel Leightley ◽

Valentina Vitiello ◽

Gabriella Bergin-Cartwright ◽

...

Keyword(s):

Cohort Studies ◽

Antibody Test ◽

Self Report ◽

Test Results ◽

Long Term Effects ◽

Antibody Testing ◽

Postgraduate Students ◽

Research Students ◽

Core Symptoms

AbstractBackgroundCohort studies of people with a history of COVID-19 infection and controls will be essential to understand the epidemiology of long-term effects. However, clinical diagnosis requires resources that are frequently restricted to the severely ill. Cohort studies may have to rely on surrogate indicators of COVID-19 illness. We describe the prevalence and overlap of five potential indicators: self-reported suspicion, self-reported core symptoms, symptom algorithm, self-reported routine test results, and home antibody testing.MethodsAn occupational cohort of staff and postgraduate students at a large London university who participated in surveys and antibody testing. Self-report items cover March to June 2020 and antibody test results from ‘lateral flow’ IgG/IgM antibody test cassettes sent to participants in June 2020.ResultsValid antibody test results were returned for 1882 participants. Of the COVID-19 indicators, the highest prevalence was core symptoms (770 participants positive, 41%), followed by participant suspicion of infection (n=509, 27%), a symptom algorithm (n=297, 16%), study antibody positive test (n=124, 6.6%) and self-report of a positive external test (n=39, 2.1%). Study antibody positive result was rare in people who had no suspicion they had experienced COVID-19 (n=4, 0.7%) or did not experience core symptoms (n=10, 1.6%). When study antibody test results were compared with earlier external antibody results in those who had reported them, the study antibody results agreed in 88% cases (kappa= 0.636), with a lower proportion testing positive on this occasion (proportion with antibodies detected 15% in study test vs 24% in external testing).DiscussionOur results demonstrate that there is some agreement between different COVID indicators, but that they a more complete story when used together. Antibody testing may provide greater certainty and be one of the only ways to detect asymptomatic cases, but is likely to under-ascertain due to weak antibody responses to mild infection, which wane over time. Cohort studies will need to review how they deal with different and sometimes conflicting indicators of COVID-19 illness in order to study the long-term outcomes of COVID-19 infection and related impacts.What is already known on this subject?Research into the effects of COVID-19 in the community is needed to respond to the pandemic. Objective testing has not been widely available and accuracy may not be high when carried out in retrospect. Many cohort studies are considering how best to measure COVID-19 infection status.What this study adds?Antibody testing is feasible, but it is possible that sensitivity may be poor. Each indicator included added different aspects to the ascertainment of COVID-19 exposure. Using combinations of self-reported and objectively measured variables, it may be possible to tailor COVID-19 indicators to the situation.

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Acceptability, usability and performance of lateral flow immunoassay tests for SARS-CoV-2 antibodies: REACT-2 study of self-testing in non-healthcare key workers

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab496 ◽

2021 ◽

Author(s):

Bethan Davies ◽

Marzieh Araghi ◽

Maya Moshe ◽

He Gao ◽

Kimberly Bennet ◽

...

Keyword(s):

Point Of Care ◽

Venous Blood ◽

Fire Service ◽

Lateral Flow ◽

Lateral Flow Immunoassay ◽

Antibody Testing ◽

Prevalence Studies ◽

Similar Performance ◽

Self Test ◽

The Uk

Abstract Background Seroprevalence studies are essential to understand the epidemiology of SARS-CoV-2. Various technologies, including laboratory assays and point-of-care self-tests, are available for antibody testing. The interpretation of seroprevalence studies requires comparative data on the performance of antibody tests. Methods In June 2020, current and former members of the UK Police forces and Fire service performed a self-test lateral flow immunoassay (LFIA), had a nurse-performed LFIA and provided a venous blood sample for ELISA . We present the prevalence of antibodies to SARS-CoV-2; the acceptability and usability of self-test LFIAs; and determine the sensitivity and specificity of LFIAs compared to laboratory ELISA. Results In this cohort of 5189 current and former members of the Police service and 263 members of the Fire service, 7.4% (396/5,348; 95% CI, 6.7-8.1) were antibody positive. Seroprevalence was 8.9% (6.9-11.4) in those under 40 years, 11.5% (8.8-15.0) in those of non-white ethnicity and 7.8% (7.1-8.7) in those currently working. Self-test LFIA had an acceptability of 97.7% and a usability of 90.0%. There was substantial agreement between within-participant LFIA results (kappa 0.80; 0.77-0.83). The LFIAs had a similar performance: compared to ELISA, sensitivity was 82.1% (77.7-86.0) self-test and 76.4% (71.9-80.5) nurse-performed with specificity of 97.8% (97.3-98.2) and 98.5% (98.1-98.8) respectively. Conclusion A greater proportion of this non-healthcare key worker cohort showed evidence of previous infection with SARS-CoV-2 than the general population at 6.0% (5.8-6.1) following the first wave in England. The high acceptability and usability reported by participants and similar performance of self-test and nurse-performed LFIAs indicate that the self-test LFIA is fit for purpose for home-testing in occupational and community prevalence studies.

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The UK Register of HIV Seroconverters: methods and analytical issues

Epidemiology and Infection ◽

10.1017/s0950268800001485 ◽

1996 ◽

Vol 117 (2) ◽

pp. 305-312 ◽

Cited By ~ 12

Author(s):

Keyword(s):

Incubation Period ◽

Disease Surveillance ◽

Hiv Transmission ◽

Communicable Disease ◽

Antibody Test ◽

Antibody Testing ◽

Hiv Seroconversion ◽

Term Basis ◽

Set Up ◽

The Uk

SummaryA Register of HIV-infected persons who have had a negative antibody test within 3 years of their first antibody positive test (seroconverters) is being set up in the UK to monitor the distribution of times from HIV seroconversion to AIDS (the incubation period) and to death. It will also provide a national resource for use by those designing studies in this group of individuals. Clinicians caring for HIV-positive persons in Genito-Urinary Medicine, Infectious Disease and other departments throughout the UK were asked to participate by providing information on eligible subjects. Most laboratories undertaking HIV antibody testing were also contacted and asked to provide the name of the attending clinician for all seroconverters identified through the HIV laboratory reporting systems of the PHLS Communicable Disease Surveillance Centre (CDSC) and the Scottish Centre for Infection and Environmental Health (SCIEH) and for any other seroconverters known to them but not identified by CDSC or SCIEH. Data items sought for the Register include: sex, ethnic group, probable route of HIV transmission, annual CD4 counts, details of therapy and prophylaxis prescribed, AIDS-defining events and vital status. Follow up information is collected annually. Wherever possible, all seroconverters known to a clinic have been identified, whether currently alive or dead, either from clinic records or laboratory reporting or both. The objective is to establish and update a complete register of seroconverters on a long-term basis to provide reliable estimates of the incubation period on which future projections of AIDS cases in the UK can be made.

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Comparative assessment of multiple COVID-19 serological technologies supports continued evaluation of point-of-care lateral flow assays in hospital and community healthcare settings

10.1101/2020.06.02.20120345 ◽

2020 ◽

Cited By ~ 7

Author(s):

Suzanne Pickering ◽

Gilberto Betancor ◽

Rui Pedro Galão ◽

Blair Merrick ◽

Adrian W. Signell ◽

...

Keyword(s):

Point Of Care ◽

Antibody Test ◽

Lateral Flow ◽

Diagnostic Tools ◽

Antibody Testing ◽

Community Healthcare ◽

Diagnostic Assays ◽

Healthcare Settings ◽

Lateral Flow Assays ◽

Diagnostic Capabilities

AbstractThere is a clear requirement for an accurate SARS-CoV-2 antibody test, both as a complement to existing diagnostic capabilities and for determining community seroprevalence. We therefore evaluated the performance of a variety of antibody testing technologies and their potential as diagnostic tools. A highly specific in-house ELISA was developed for the detection of anti-spike (S), -receptor binding domain (RBD) and -nucleocapsid (N) antibodies and used for the cross-comparison of ten commercial serological assays – a chemiluminescence-based platform, two ELISAs and seven colloidal gold lateral flow immunoassays (LFIAs) – on an identical panel of 110 SARS-CoV-2-positive samples and 50 pre-pandemic negatives. There was a wide variation in the performance of the different platforms, with specificity ranging from 82% to 100%, and overall sensitivity from 60.9% to 87.3%. However, the head-to-head comparison of multiple sero-diagnostic assays on identical sample sets revealed that performance is highly dependent on the time of sampling, with sensitivities of over 95% seen in several tests when assessing samples from more than 20 days post onset of symptoms. Furthermore, these analyses identified clear outlying samples that were negative in all tests, but were later shown to be from individuals with mildest disease presentation. Rigorous comparison of antibody testing platforms will inform the deployment of point-of-care technologies in healthcare settings and their use in the monitoring of SARS-CoV-2 infections.

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UK Fiscal Squeezes over a Century

10.1093/oso/9780198779612.003.0002 ◽

2017 ◽

Author(s):

Christopher Hood ◽

Rozana Himaz

Keyword(s):

Data Sources ◽

Fiscal Consolidation ◽

Financial Outcomes ◽

Financial Conditions ◽

Deficit Reduction ◽

Before And After ◽

The Uk ◽

Changes Over Time ◽

Spending Cuts ◽

Over Time

This chapter draws on historical statistics reporting financial outcomes for spending, taxation, debt, and deficit for the UK over a century to (a) identify quantitatively and compare the main fiscal squeeze episodes (i.e. major revenue increases, spending cuts, or both) in terms of type (soft squeezes and hard squeezes, spending squeezes, and revenue squeezes), depth, and length; (b) compare these periods of austerity against measures of fiscal consolidation in terms of deficit reduction; and (c) identify economic and financial conditions before and after the various squeezes. It explores the extent to which the identification of squeeze episodes and their classification is sensitive to which thresholds are set and what data sources are used. The chapter identifies major changes over time that emerge from this analysis over the changing depth and types of squeeze.

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Population (Antibody) Testing for COVID-19—Technical Challenges, Application and Relevance, an English Perspective

Vaccines ◽

10.3390/vaccines9060550 ◽

2021 ◽

Vol 9 (6) ◽

pp. 550

Author(s):

Peter A. C. Maple

Keyword(s):

National Level ◽

Herd Immunity ◽

Population Based ◽

Biological Properties ◽

Limited Extent ◽

Antibody Testing ◽

Serum Samples ◽

Oral Fluids ◽

Antibody Assays ◽

The Uk

In the UK, population virus or antibody testing using virus swabs, serum samples, blood spots or oral fluids has been performed to a limited extent for several diseases including measles, mumps, rubella and hepatitis and HIV. The collection of population-based infection and immunity data is key to the monitoring of disease prevalence and assessing the effectiveness of interventions such as behavioural modifications and vaccination. In particular, the biological properties of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its interaction with the human host have presented several challenges towards the development of population-based immunity testing. Measuring SARS-CoV-2 immunity requires the development of antibody assays of acceptable sensitivity and specificity which are capable of accurately detecting seroprevalence and differentiating protection from non-protective responses. Now that anti-COVID-19 vaccines are becoming available there is a pressing need to measure vaccine efficacy and the development of herd immunity. The unprecedented impact of the SARS-CoV-2 pandemic in the UK in terms of morbidity, mortality, and economic and social disruption has mobilized a national scientific effort to learn more about this virus. In this article, the challenges of testing for SARS-CoV-2 infection, particularly in relation to population-based immunity testing, will be considered and examples given of relevant national level studies.

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Topological and Morphological Controls on Morphodynamics of Salt Marsh Interiors

Journal of Marine Science and Engineering ◽

10.3390/jmse9030311 ◽

2021 ◽

Vol 9 (3) ◽

pp. 311

Author(s):

Ben R. Evans ◽

Iris Möller ◽

Tom Spencer

Keyword(s):

Salt Marsh ◽

Salt Marshes ◽

East Coast ◽

Marsh Surface ◽

Coastal Environments ◽

Coastal System ◽

Morphological Segmentation ◽

The Usa ◽

The Uk ◽

Over Time

Salt marshes are important coastal environments and provide multiple benefits to society. They are considered to be declining in extent globally, including on the UK east coast. The dynamics and characteristics of interior parts of salt marsh systems are spatially variable and can fundamentally affect biotic distributions and the way in which the landscape delivers ecosystem services. It is therefore important to understand, and be able to predict, how these landscape configurations may evolve over time and where the greatest dynamism will occur. This study estimates morphodynamic changes in salt marsh areas for a regional domain over a multi-decadal timescale. We demonstrate at a landscape scale that relationships exist between the topology and morphology of a salt marsh and changes in its condition over time. We present an inherently scalable satellite-derived measure of change in marsh platform integrity that allows the monitoring of changes in marsh condition. We then demonstrate that easily derived geospatial and morphometric parameters can be used to determine the probability of marsh degradation. We draw comparisons with previous work conducted on the east coast of the USA, finding differences in marsh responses according to their position within the wider coastal system between the two regions, but relatively consistent in relation to the within-marsh situation. We describe the sub-pixel-scale marsh morphometry using a morphological segmentation algorithm applied to 25 cm-resolution maps of vegetated marsh surface. We also find strong relationships between morphometric indices and change in marsh platform integrity which allow for the inference of past dynamism but also suggest that current morphology may be predictive of future change. We thus provide insight into the factors governing marsh degradation that will assist the anticipation of adverse changes to the attributes and functions of these critical coastal environments and inform ongoing ecogeomorphic modelling developments.

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Resource and waste quantification scenarios for wind turbine decommissioning in the United Kingdom

Waste Disposal & Sustainable Energy ◽

10.1007/s42768-020-00057-6 ◽

2020 ◽

Author(s):

Kiran Tota-Maharaj ◽

Alexander McMahon

Keyword(s):

United Kingdom ◽

Waste Management ◽

Wind Turbine ◽

End Of Life ◽

Wind Turbines ◽

Rapid Rise ◽

The United Kingdom ◽

Management Procedures ◽

The Uk ◽

Over Time

AbstractWind power produces more electricity than any other form of renewable energy in the United Kingdom (UK) and plays a key role in decarbonisation of the grid. Although wind energy is seen as a sustainable alternative to fossil fuels, there are still several environmental impacts associated with all stages of the lifecycle of a wind farm. This study determined the material composition for wind turbines for various sizes and designs and the prevalence of such turbines over time, to accurately quantify waste generation following wind turbine decommissioning in the UK. The end of life stage is becoming increasingly important as a rapid rise in installation rates suggests an equally rapid rise in decommissioning rates can be expected as wind turbines reach the end of their 20–25-year operational lifetime. Waste data analytics were applied in this study for the UK in 5-year intervals, stemming from 2000 to 2039. Current practices for end of life waste management procedures have been analysed to create baseline scenarios. These scenarios have been used to explore potential waste management mitigation options for various materials and components such as reuse, remanufacture, recycling, and heat recovery from incineration. Six scenarios were then developed based on these waste management options, which have demonstrated the significant environmental benefits of such practices through quantification of waste reduction and greenhouse gas (GHG) emissions savings. For the 2015–2019 time period, over 35 kilotonnes of waste are expected to be generated annually. Overall waste is expected to increase over time to more than 1200 kilotonnes annually by 2039. Concrete is expected to account for the majority of waste associated with wind turbine decommissioning initially due to foundations for onshore turbines accounting for approximately 80% of their total weight. By 2035–2039, steel waste is expected to account for almost 50% of overall waste due to the emergence of offshore turbines, the foundations of which are predominantly made of steel.

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In-work Universal Credit: Claimant Experiences of Conditionality Mismatches and Counterproductive Benefit Sanctions

Journal of Social Policy ◽

10.1017/s0047279420000562 ◽

2020 ◽

pp. 1-19

Author(s):

SHARON WRIGHT ◽

PETER DWYER

Keyword(s):

Social Security ◽

Job Search ◽

Longitudinal Research ◽

Working Hours ◽

Unique Contribution ◽

Working Age ◽

Micro Level ◽

Benefit Sanctions ◽

The Uk ◽

Over Time

Abstract Universal Credit is the UK’s globally innovative social security reform that replaces six means tested benefits with one monthly payment for working age claimants - combining social security and tax credit systems. Universal Credit expands welfare conditionality via mandatory job search conditions to enhance ‘progression’ amongst working claimants by requiring extra working hours or multiple jobs. This exposes low paid workers to tough benefit sanctions for non-compliance, which could remove essential income indefinitely or for fixed periods of up to three years. Our unique contribution is to establish how this new regime is experienced at micro level by in-work claimants over time. We present findings from Qualitative Longitudinal Research (141 interviews with 58 claimants, 2014-17), to demonstrate how UC impacts on in-work recipients and how conditionality produces a new coerced worker-claimant model of social support. We identify a series of welfare conditionality mismatches and conclude that conditionality for in-work claimants is largely counterproductive. This implies a redesign of the UK system and serves as an international warning to potential policy emulators.

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A Nationwide Survey of COVID-19 Testing in LGBTQ+ Populations in the United States

Public Health Reports ◽

10.1177/00333549211018190 ◽

2021 ◽

pp. 003335492110181

Author(s):

Richard J. Martino ◽

Kristen D. Krause ◽

Marybec Griffin ◽

Caleb LoSchiavo ◽

Camilla Comer-Carruthers ◽

...

Keyword(s):

United States ◽

Gay Men ◽

Antibody Test ◽

Nationwide Survey ◽

The United States ◽

Sociodemographic Characteristics ◽

Full Time ◽

Test Results ◽

Antibody Testing ◽

And Gender

Objectives Lesbian, gay, bisexual, transgender, or queer and questioning (LGBTQ+) people and populations face myriad health disparities that are likely to be evident during the COVID-19 pandemic. The objectives of our study were to describe patterns of COVID-19 testing among LGBTQ+ people and to differentiate rates of COVID-19 testing and test results by sociodemographic characteristics. Methods Participants residing in the United States and US territories (N = 1090) aged ≥18 completed an internet-based survey from May through July 2020 that assessed COVID-19 testing and test results and sociodemographic characteristics, including sexual orientation and gender identity (SOGI). We analyzed data on receipt and results of polymerase chain reaction (PCR) and antibody testing for SARS-CoV-2 and symptoms of COVID-19 in relation to sociodemographic characteristics. Results Of the 1090 participants, 182 (16.7%) received a PCR test; of these, 16 (8.8%) had a positive test result. Of the 124 (11.4%) who received an antibody test, 45 (36.3%) had antibodies. Rates of PCR testing were higher among participants who were non–US-born (25.4%) versus US-born (16.3%) and employed full-time or part-time (18.5%) versus unemployed (10.8%). Antibody testing rates were higher among gay cisgender men (17.2%) versus other SOGI groups, non–US-born (25.4%) versus US-born participants, employed (12.6%) versus unemployed participants, and participants residing in the Northeast (20.0%) versus other regions. Among SOGI groups with sufficient cell sizes (n > 10), positive PCR results were highest among cisgender gay men (16.1%). Conclusions The differential patterns of testing and positivity, particularly among gay men in our sample, confirm the need to create COVID-19 public health messaging and programming that attend to the LGBTQ+ population.

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