Life span of Covid-19 antibodies following infection in a sample worker population in Qatar

Background: COVID-19 antibodies’ longevity following infection is still unclear. Early data brought hope that acquired immunity was possible but subsequent studies suggested that immune protection might be short-lived. The results of recent studies provide greater insight into the human immune response to COVID-19. The Qatar Gas medical department’s strategy in preventing spread of infection among offshore and onshore workers consisted of maximizing the opportunities for COVID-19 polymerise chain reaction (PCR) and antibody testing. A large amount of data revealing the possible lifespan of COVID-19 antibodies in the study population was collected. Methods: Out of hundreds of employees who volunteered in this study about seroprevalance of COVID-19 antibodies, 52 whose results were reactive were tested for COVID-19 PCR before being selected. Employees with reactive or inconclusive PCR test results were excluded. Age, medical/surgical/social history, apart from past COVID-19 infection, were not selection criteria. We measured the period of time between the date of diagnosis and the antibody test result, segregating those still reactive from those who tested non-reactive at any point in time. The reactive group were retested for antibodies every 90 days as long as results continued to be reactive. Any cured employee was retested if they developed symptoms or was exposed to a confirmed positive case, to rule out the possibility of re-infection during this timeframe. Results: Only one employee was non-reactive after 110 days of COVID-19 PCR positive test result. 22 employees tested reactive although their PCR result had been negative. 30 employees tested reactive after a positive PCR with an average duration of 145 days, the shortest and longest being 24 and 223 respectively. Conclusion: We determined that antibodies’ longevity may extend to more than 6 months following COVID-19 infection and that there may be an early decay of antibodies in a limited proportion of the population, however further studies are recommended on larger populations. We noticed no cases of COVID-19 reinfection.

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Understanding COVID-19 Epidemiology and Implications for Control: The Experience from a Greek Semi-Closed Community

Journal of Clinical Medicine ◽

10.3390/jcm10132765 ◽

2021 ◽

Vol 10 (13) ◽

pp. 2765

Author(s):

Ourania S. Kotsiou ◽

Dimitrios Papagiannis ◽

Evangelos C. Fradelos ◽

Garyfallia Perlepe ◽

Angeliki Miziou ◽

...

Keyword(s):

Low Cost ◽

Herd Immunity ◽

Rapid Test ◽

Antibody Test ◽

Antibody Testing ◽

Past Infection ◽

Positive Antibody ◽

Study Population ◽

Clinical Correlations ◽

Test Result

Background: We aimed to estimate the SARS-CoV-2 antigen and antibody seroprevalence in one of the worst-affected by the pandemic semi-closed communities in Greece, Deskati, and evaluate the sociodemographic and clinical correlations of functional antibody responses. Methods: The Ag2019n-CoV V1310/V1330 Rapid Test (Prognosis Biotech, Greece) was used for antigen detection. The Rapid Test 2019-nCoV Total Ig, V1210/V1230 (Prognosis Biotech, Greece), and the SARS-CoV-2 IgG II Quant method (Architect, Abbott, Illinois, USA) were used for antibody testing. Results: None of the participants had a positive antigen result. SARS-CoV-2 seropositivity ranged from 13% to 45% in the study population, depending on the method. One-third of the participants with known past infection had a positive antibody test result 77 ± 13 days after infection. Two-fifths of infections determined by serology were asymptomatic. The advancing age and hospitalization predicted seropositivity among patients with past infection. Half of the participants who tested positive for antibodies were not aware of past infection. Conclusions: High-burden contexts in Greece, such as Deskati, are not so far from herd immunity thresholds. We highlighted the value of low-cost serosurveys targeting both symptomatic and asymptomatic populations to evaluate the natural immune response to SARS-CoV-2 in nonvaccinated susceptibles and design evidence-based policies for lifting lockdowns.

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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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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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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

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa515.1909 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S849-S850

Author(s):

David McCormick ◽

Tracy Scott ◽

Jesse Chavez ◽

Kay Wilcox ◽

Grace E Marx ◽

...

Keyword(s):

Native American ◽

Venous Blood ◽

Antibody Test ◽

Sociodemographic Factors ◽

Mitigation Strategies ◽

Homeless Shelters ◽

Test Results ◽

Rt Pcr ◽

Antibody Testing ◽

Antibody Tests

Abstract Background The 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. Methods In 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. Results From 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 Conclusion A 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

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Behavioural responses to SARS-CoV-2 antibody testing in England: REACT-2 study

Wellcome Open Research ◽

10.12688/wellcomeopenres.16662.1 ◽

2021 ◽

Vol 6 ◽

pp. 203

Author(s):

Rozlyn Redd ◽

Emily Cooper ◽

Christina Atchison ◽

Isabella Pereira ◽

Polly Hollings ◽

...

Keyword(s):

Research Programme ◽

Antibody Test ◽

Test Results ◽

Antibody Testing ◽

Community Based ◽

Prevalence Studies ◽

Behavioural Responses ◽

Self Testing ◽

Community Transmission

Background: This study assesses the behavioural responses to SARS-CoV-2 antibody test results as part of the REal-time Assessment of Community Transmission-2 (REACT-2) research programme, a large community-based surveillance study of antibody prevalence in England. Methods: A follow-up survey was conducted six weeks after the SARS-CoV-2 antibody test. The follow-up survey included 4500 people with a positive result and 4039 with a negative result. Reported changes in behaviour were assessed using difference-in-differences models. A nested interview study was conducted with 40 people to explore how they thought through their behavioural decisions. Results: While respondents reduced their protective behaviours over the six weeks, we did not find evidence that positive test results changed participant behaviour trajectories in relation to the number of contacts the respondents had, for leaving the house to go to work, or for leaving the house to socialise in a personal place. The qualitative findings supported these results. Most people did not think that they had changed their behaviours because of their test results, however they did allude to some changes in their attitudes and perceptions around risk, susceptibility, and potential severity of symptoms. Conclusions: We found limited evidence that knowing your antibody status leads to behaviour change in the context of a research study. While this finding should not be generalised to widespread self-testing in other contexts, it is reassuring given the importance of large prevalence studies, and the practicalities of doing these at scale using self-testing with lateral flow immunoassay (LFIA).

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China NMPA perspective on clinical evaluation of SARS-CoV-2 antibody test reagents in the process of emergency approval

Bioanalysis ◽

10.4155/bio-2020-0188 ◽

2020 ◽

Author(s):

Yunfeng Lv ◽

Jingyun He ◽

Rongzhi Liu ◽

Yu Gao ◽

Chao Xu ◽

...

Keyword(s):

Early Stage ◽

Antibody Test ◽

Standard Test ◽

Test Method ◽

Antibody Detection ◽

Test Results ◽

Antibody Testing ◽

National Medical ◽

Key Points ◽

Antigen Antibody

Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 antibody testing an important supplement to nucleic acid testing. In the process of emergency approval, the Center for Medical Device Evaluation of the China National Medical Products Administration released The Key Points of Technical Review for the Registration of SARS-CoV-2 Antigen/Antibody Detection Reagents. The Clinical Study Requirement section of the Key Point has put forward requirements in terms of reference methods and subject enrolment among others, which can ensure that the test results can meet the clinical needs. This article draws on the experience of the China NMPA in evaluating diagnostic reagents used to supplement the gold standard test method in the early stage of an epidemic of an infectious disease, as well as to serve as reference for clinicians and regulators.

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The Avon Longitudinal Study of Parents and Children - A resource for COVID-19 research: Antibody testing results, April – June 2021

Wellcome Open Research ◽

10.12688/wellcomeopenres.17294.1 ◽

2021 ◽

Vol 6 ◽

pp. 283

Author(s):

Daniel Major-Smith ◽

Sarah Matthews ◽

Thomas Breeze ◽

Michael Crawford ◽

Hannah Woodward ◽

...

Keyword(s):

Longitudinal Study ◽

Generational Differences ◽

Natural Infection ◽

Antibody Test ◽

Sociodemographic Factors ◽

Population Based ◽

Antibody Testing ◽

Parents And Children ◽

Avon Longitudinal Study ◽

Test Result

The Avon Longitudinal Study of Parents and Children (ALSPAC) is a prospective population-based cohort which recruited pregnant women in 1990-1992 and has followed these women, their partners (Generation 0; G0) and their offspring (Generation 1; G1) ever since. The study reacted rapidly and repeatedly to the coronavirus disease 2019 (COVID-19) pandemic, deploying multiple online questionnaires and a previous home-based antibody test in October 2020. A second antibody test, in collaboration with ten other longitudinal population studies, was completed by 4,622 ALSPAC participants between April and June 2021. Of participants with a valid spike protein antibody test result (4,241; 8.2% void), indicating antibody response to either COVID-19 vaccination or natural infection, 3,172 were positive (74.8%). Generational differences were substantial, with 2,463/2,555 G0 participants classified positive (96.4%) compared to 709/1,686 G1 participants (42.1%). Of participants with a valid nucleocapsid antibody test result (4,199; 9.2% void), suggesting potential and recent natural infection, 493 were positive (11.7%); with 248/2,526 G0 participants (9.8%) and 245/1,673 G1 participants (14.6%) testing positive, respectively. We also compare results for this round of testing to that undertaken in October 2020. Future work will combine these test results with additional sources of data to identify participants’ COVID-19 infection and vaccination status. These ALSPAC COVID-19 serology data are being complemented with linkage to health records and Public Health England pillar testing results as they become available, in addition to four previous questionnaire waves and a prior antibody test. Data have been released as an update to the previous COVID-19 datasets. These comprise: 1) a standard dataset containing all participant responses to all four previous questionnaires with key sociodemographic factors; and 2) individual participant-specific release files enabling bespoke research across all areas supported by the study. This data note describes the second ALSPAC antibody test and the data obtained from it.

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Behavioural responses to SARS-CoV-2 antibody testing in England: REACT-2 study

Wellcome Open Research ◽

10.12688/wellcomeopenres.16662.2 ◽

2021 ◽

Vol 6 ◽

pp. 203

Author(s):

Rozlyn Redd ◽

Emily Cooper ◽

Christina Atchison ◽

Isabella Pereira ◽

Polly Hollings ◽

...

Keyword(s):

Research Programme ◽

Antibody Test ◽

Test Results ◽

Antibody Testing ◽

Community Based ◽

Prevalence Studies ◽

Behavioural Responses ◽

Self Testing ◽

Community Transmission

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High prevalence of symptoms among Brazilian subjects with antibodies against SARS-CoV-2: a nationwide household survey

10.1101/2020.08.10.20171942 ◽

2020 ◽

Cited By ~ 1

Author(s):

Ana Maria Baptista Menezes ◽

Cesar G Victora ◽

Fernando P Hartwig ◽

Mariangela F Silveira ◽

Bernardo L Horta ◽

...

Keyword(s):

Recursive Partitioning ◽

Indirect Evidence ◽

Household Survey ◽

Antibody Test ◽

Demographic Characteristics ◽

Test Results ◽

High Prevalence ◽

Using Data ◽

Test Result ◽

Rapid Antibody

Since the beginning of the pandemic of COVID-19, there has been a widespread assumption that most infected persons are asymptomatic. A frequently-cited early study from China suggested that 86% of all infections were undocumented, which was used as indirect evidence that patients were asymptomatic. Using data from the most recent wave of the EPICOVID19 study, a nationwide household-based survey including 133 cities from all states of Brazil, we estimated the proportion of people with and without antibodies for SARS-CoV-2 who were asymptomatic, which symptoms were most frequently reported, the number of symptoms reported and the association between symptomatology and socio-demographic characteristics. We were able to test 33,205 subjects using a rapid antibody test that was previously validated. Information on symptoms was collected before participants received the test result. Out of 849 (2.7%) participants who tested positive for SARS-CoV-2 antibodies, only 12.1% (95%CI 10.1-14.5) reported no symptoms since the start of the pandemic, compared to 42.2% (95%CI 41.7-42.8) among those who tested negative. The largest difference between the two groups was observed for changes in smell or taste (56.5% versus 9.1%, a 6.2-fold difference). Symptoms change in smell or taste, fever and myalgia were most likely to predict positive test results as suggested by recursive partitioning tree analysis. Among individuals without any of these three symptoms (74.2% of the sample), only 0.8% tested positive, compared to 18.3% of those with both fever and changes in smell or taste. Most subjects with antibodies against SARS-CoV-2 in Brazil are symptomatic, even though most present only mild symptoms.

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Applying the proportionality principle to COVID-19 antibody testing

Journal of Law and the Biosciences ◽

10.1093/jlb/lsaa058 ◽

2020 ◽

Vol 7 (1) ◽

Author(s):

H D Gunnarsdóttir ◽

M S Sinha ◽

S Gerke ◽

T Minssen

Keyword(s):

European Union ◽

Antibody Test ◽

International Travel ◽

Differential Treatment ◽

Individual Freedom ◽

Test Results ◽

The European Union ◽

Antibody Testing ◽

Proportionality Principle

Abstract As the COVID-19 pandemic continues to ravage the globe, many nations have started to relax stringent restrictions in an effort to restart the economy. While Member States of the European Union have approached reopening without the use of antibody testing for COVID-19, such testing may be central to a long-term, sustainable strategy for international travel, employment, and the allocation and monitoring of vaccines. As the use of antibody testing to dictate the enjoyment of individual freedom remains highly controversial, we describe its use in the context of three case studies (return to the workplace, travel and vaccination), applying the substantive legal balancing entailed in the proportionality principle. Differential treatment of individuals based on COVID-19 antibody test results can be justified through the proportionality principle, which offers a sound dividing line between a reasonable and legitimate response and an unjust and discriminatory response.

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