scholarly journals Repeated seroprevalence of anti-SARS-CoV-2 IgG antibodies in a population-based sample

2020 ◽  
Author(s):  
Silvia Stringhini ◽  
Ania Wisniak ◽  
Giovanni Piumatti ◽  
Andrew S. Azman ◽  
Stephen A. Lauer ◽  
...  
Keyword(s):  
Test Performance ◽  
Wide Spectrum ◽  
Herd Immunity ◽  
Population Based ◽  
Bayesian Regression ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Case Definitions ◽  
Adult Participants ◽  
Household Members

AbstractBackgroundAssessing the burden of COVID-19 based on medically-attended case counts is suboptimal given its reliance on testing strategy, changing case definitions and the wide spectrum of disease presentation. Population-based serosurveys provide one avenue for estimating infection rates and monitoring the progression of the epidemic, overcoming many of these limitations.MethodsTaking advantage of a pool of adult participants from population-representative surveys conducted in Geneva, Switzerland, we implemented a study consisting of 8 weekly serosurveys among these participants and their household members older than 5 years. We tested each participant for anti-SARS-CoV-2-IgG antibodies using a commercially available enzyme-linked immunosorbent assay (Euroimmun AG, Lübeck, Germany). We estimated seroprevalence using a Bayesian regression model taking into account test performance and adjusting for the age and sex of Geneva’s population.ResultsIn the first three weeks, we enrolled 1335 participants coming from 633 households, with 16% <20 years of age and 53.6% female, a distribution similar to that of Geneva. In the first week, we estimated a seroprevalence of 3.1% (95% CI 0.2-5.99, n=343). This increased to 6.1% (95% CI 2.69.33, n=416) in the second, and to 9.7% (95% CI 6.1-13.11, n=576) in the third week. We found that 5-19 year-olds (6.0%, 95% CI 2.3-10.2%) had similar seroprevalence to 20-49 year olds (8.5%, 95%CI 4.99-11.7), while significantly lower seroprevalence was observed among those 50 and older (3.7%, 95% CI 0.99-6.0, p=0.0008).InterpretationAssuming that the presence of IgG antibodies is at least in the short-term associated with immunity, these results highlight that the epidemic is far from burning out simply due to herd immunity. Further, no differences in seroprevalence between children and middle age adults are observed. These results must be considered as Switzerland and the world look towards easing restrictions aimed at curbing transmission.

scholarly journals Seroprevalence of anti-SARS-CoV-2 IgG antibodies, risk factors for infection and associated symptoms in Geneva, Switzerland: a population-based study

2021 ◽  
pp. 140349482110480
Author(s):  
Aude Richard ◽  
Ania Wisniak ◽  
Javier Perez-Saez ◽  
Henri Garrison-Desany ◽  
Dusan Petrovic ◽  
...  
Keyword(s):  
Risk Factors ◽  
Test Performance ◽  
Credible Interval ◽  
The Elderly ◽  
Population Based ◽  
Igg Antibodies ◽  
Population Based Study ◽  
Associated Symptoms ◽  
Household Members ◽  
Occupation Level

Aims: To assess SARS-CoV-2 seroprevalence over the first epidemic wave in the canton of Geneva, Switzerland, as well as risk factors for infection and symptoms associated with IgG seropositivity. Methods: Between April and June 2020, former participants of a representative survey of the 20–74-year-old population of canton Geneva were invited to participate in the study, along with household members aged over 5 years. Blood samples were tested for anti-SARS-CoV-2 immunoglobulin G. Questionnaires were self-administered. We estimated seroprevalence with a Bayesian model accounting for test performance and sampling design. Results: We included 8344 participants, with an overall adjusted seroprevalence of 7.8% (95% credible interval 6.8–8.9). Seroprevalence was highest among 18–49 year-olds (9.5%), and lowest in 5–9-year-old children (4.3%) and individuals >65 years (4.7-5.4%). Odds of seropositivity were significantly reduced for female retirees and unemployed men compared to employed individuals, and smokers compared to non-smokers. We found no significant association between occupation, level of education, neighborhood income and the risk of being seropositive. The symptom most strongly associated with seropositivity was anosmia/dysgeusia. Conclusions: Anti-SARS-CoV-2 population seroprevalence remained low after the first wave in Geneva. Socioeconomic factors were not associated with seropositivity in this sample. The elderly, young children and smokers were less frequently seropositive, although it is not clear how biology and behaviours shape these differences.

scholarly journals Association between Chlamydia trachomatis antibodies and subfertility in the Northern Finland Birth Cohort 1966 (NFBC 1966), at the age of 31 years

2004 ◽  
Vol 132 (5) ◽  
pp. 977-984 ◽  
Author(s):  
L. KARINEN ◽  
A. POUTA ◽  
A.-L. HARTIKAINEN ◽  
A. BLOIGU ◽  
M. PALDANIUS ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Birth Cohort ◽  
Population Sample ◽  
Population Based ◽  
Enzyme Linked Immunosorbent Assay ◽  
Health Examination ◽  
General Population Sample ◽  
Igg Antibodies ◽  
Female Partners ◽  
Specific Serum

The objective of this study was to assess the serological association between previous Chlamydia trachomatis infection and subfertility in a general population sample. A nested case (n=493)-control (n=986) study in a population-based birth cohort consisting of 12058 live births from the year 1966 was conducted. The analysis was restricted to those 6007 cohort members who replied to a postal inquiry and participated in a health examination including blood samples at the age of 31 years. The presence of C. trachomatis-specific serum IgG antibodies was screened by a synthetic peptide-based enzyme-linked immunosorbent assay. All the positive sera were further tested by the microimmunofluorescence method using immunotype pools and individual immunotypes of C. trachomatis as antigens. An association was found between the detection of immunotype-specific C. trachomatis antibodies and subfertility both in men and women. The results of the present study confirm the serological association between past C. trachomatis infections and subfertility in male or female partners of the couple in the population-based sample.

scholarly journals SARS-CoV-2 antibody seroprevalence in Lebanon: findings from the first nationwide serosurvey

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Abbas Hoballah ◽  
Rana El Haidari ◽  
Ghina Siblany ◽  
Fadi Abdel Sater ◽  
Samir Mansour ◽  
...  
Keyword(s):  
Test Performance ◽  
Point Of Care ◽  
Vaccination Campaign ◽  
Herd Immunity ◽  
Age Groups ◽  
Rapid Test ◽  
Population Based ◽  
P Value ◽  
Cumulative Number ◽  
Population Weight

Abstract Background Lebanon, a small country in the Middle East, remains severely affected by the COVID-19 pandemic. Seroprevalence surveys of anti-SARS-CoV-2 antibodies provide accurate estimates of SARS-CoV-2 infection and hence evaluate the extent of the pandemic. The present study aimed to evaluate the prevalence of SARS-CoV-2 antibodies in Lebanon and to compare the estimated cumulative number of COVID-19 cases with the officially registered number of laboratory-confirmed cases up to January 15, 2021. Methods A nationwide population-based serosurvey study was conducted in Lebanon between December 7, 2020, and January 15, 2021, before the initiation of the national vaccination program. The nCOVID-19 IgG & IgM point-of-care (POCT) rapid test was used to detect the presence of anti-SARS-COV-2 immunoglobulin G (IgG) in the blood. Seroprevalence was estimated after weighting for sex, age, and area of residence and adjusting for the test performance. Results Of the 2058 participants, 329 were positive for IgG SARS-COV-2, resulting in a crude seroprevalence of 16.0% (95% CI 14.4–17.6). The weighed seroprevalence was 15.9% (95% CI of 14.4 and 17.4). After adjusting for test performance, the population weight-adjusted seroprevalence was 18.5% (95% CI 16.8–20.2). This estimate implies that 895,770 individuals of the general population were previously infected by COVID-19 up to January 15, 2021 in Lebanon. The overall estimated number of subjects with previous SARS-CoV-2 infection was three times higher than the officially reported cumulative number of confirmed cases. Seroprevalence was similar across age groups and sexes (p-value > 0.05). However, significant differences were revealed across governorates. Conclusions Our results suggest that the Lebanese population is still susceptible to SARS-CoV-2 infection and far from achieving herd immunity. These findings represent an important contribution to the surveillance of the COVID-19 pandemic in Lebanon and to the understanding of how this virus spreads. Continued surveillance for COVID-19 cases and maintaining effective preventive measures are recommended to control the epidemic spread in conjunction with a national vaccination campaign to achieve the desired level of herd immunity against COVID-19.

scholarly journals Prevalence and associated characteristics of anti-SARS-CoV-2 antibodies in Mexico 5 months after pandemic arrival

2020 ◽  
Author(s):  
Cristina Díaz-Salazar ◽  
Adriana Sánchez-García ◽  
René Rodríguez-Gutiérrez ◽  
Adrián Camacho-Ortiz ◽  
Donato Saldívar-Rodríguez ◽  
...  
Keyword(s):  
Test Performance ◽  
Clinical Characteristics ◽  
Statistical Significance ◽  
Herd Immunity ◽  
Epidemiological Data ◽  
Epidemiological Surveillance ◽  
Continuous Variables ◽  
Igg Antibodies ◽  
Logistic Regression Models ◽  
Student’S T

Abstract Background: Seroprevalence of anti-SARS-CoV-2 antibodies is now available in several world regions to better estimate transmission dynamics. However, to date, there is no epidemiological data regarding anti-SARS-CoV-2 prevalence in Mexico. Therefore, we aimed to determine the prevalence of anti-SARS-CoV-2 antibodies and define the clinical and demographic characteristics associated with seroprevalence in a institutionalized population.Methods: We conducted a serological survey in Ciudad Guadalupe, NL, Mexico. Institutionalized employees voluntarily participated during July 2020. Demographic and clinical characteristics were collected at the time of blood sampling to analyze the associated characteristics. IgM/IgG antibodies were determined using a qualitative chemiluminescent immunoassay. We reported the raw and the adjusted seroprevalence for test performance characteristics. Descriptive statistics were used for categorical and continuous variables. Statistical significance was tested using the Chi-squared test, Student’s t-test and the Mann-Whitney. Logistic regression models and the odds ratios (adjusted and unadjusted) were used to estimate the association of demographic and clinical characteristics.Results: Of the 3,268 participants included, 193 (5.9%, 95% CI 5.1-6.8) tested positive for IgM/IgG against SARS-CoV-2. Adjusted prevalence by the immunoassay diagnostic performance resulted in a prevalence of 5.7 (95% CI 4.9-6.6). Gender, city of residence, and comorbidities did not show any association with having IgM/IgG antibodies. A total of 114 out of 193 (59.1%) subjects with a positive test were asymptomatic, and the odds of being positive were higher in those who reported symptoms of COVID-19 in the previous four weeks to the survey (OR 4.1, 95% CI 2.9-5.5).Conclusions: There is a low rate of SARS-CoV-2 infection among institutionalized employees that have continuously been working during the pandemic. Six in ten infections were asymptomatic, and seroprevalence is low and still far from herd immunity. Epidemiological surveillance and preventive measures should be mandatory.

scholarly journals Population-based seroprevalence of SARS-CoV-2 and the herd immunity threshold in Maranhão

2020 ◽  
Vol 54 ◽  
pp. 131
Author(s):  
Antônio Augusto Moura da Silva ◽  
Lídio Gonçalves Lima-Neto ◽  
Conceição de Maria Pedrozo e Silva de Azevedo ◽  
Léa Márcia Melo da Costa ◽  
Maylla Luanna Barbosa Martins Bragança ◽  
...  
Keyword(s):  
Herd Immunity ◽  
Household Survey ◽  
Population Based ◽  
Igg Antibodies ◽  
Infection Rates ◽  
Qualitative Detection ◽  
Roche Diagnostics ◽  
Local Herd ◽  
Pharmaceutical Interventions ◽  
Population Based Survey

OBJECTIVE: To estimate the seroprevalence of SARS-CoV-2 in the state of Maranhão, Brazil. METHODS: A population-based household survey was performed, from July 27, 2020 to August 8, 2020. The estimates considered clustering, stratification and non-response. Qualitative detection of IgM and IgG antibodies was performed in a fully-automated Elecsys® Anti-SARS-CoV-2 electrochemiluminescence immunoassay on the Cobas® e601 analyzer (Roche Diagnostics). RESULTS: In total, 3,156 individuals were interviewed. Seroprevalence of total antibodies against SARS-CoV-2 was 40.4% (95%CI 35.6-45.3). Population adherence to non-pharmaceutical interventions was higher at the beginning of the pandemic than in the last month. SARS-CoV-2 infection rates were significantly lower among mask wearers and among those who maintained social and physical distancing in the last month compared to their counterparts. Among the infected, 26.0% were asymptomatic. The infection fatality rate (IFR) was 0.14%, higher for men and older adults. The IFR based on excess deaths was 0.28%. The ratio of estimated infections to reported cases was 22.2. CONCLUSIONS: To the best of our knowledge, the seroprevalence of SARS-CoV-2 estimated in this population-based survey is one of the highest reported. The local herd immunity threshold may have been reached or might be reached soon.

scholarly journals Seroprevalence of anti-SARS-CoV-2 antibodies in Iquitos, Loreto, Peru

2021 ◽  
Author(s):  
Carlos Álvarez-Antonio ◽  
Graciela Meza-Sánchez ◽  
Carlos Calampa ◽  
Wilma Casanova ◽  
Cristiam Carey ◽  
...  
Keyword(s):  
Test Performance ◽  
Herd Immunity ◽  
Age Groups ◽  
Rapid Test ◽  
Prevalence Ratio ◽  
Population Based ◽  
Current Data ◽  
Survey Analysis ◽  
Population Based Study

SummaryBackgroundDetection of SARS-CoV-2 antibodies among people at risk is critical for understanding both the prior transmission of COVID-19 and vulnerability of the population to the continuing transmission and, when done serially, the intensity of ongoing transmission over an interval in a community. In this study, we estimated the seroprevalence of COVID-19 in a representative population-based cohort of Iquitos, one of the regions with the highest mortality rates from COVID-19 in Peru, where a devastating number of cases occurred in March 2020.MethodsWe conducted a population-based study of transmission tested each participant using the COVID-19 IgG/IgM Rapid Test from Orient Gene Biotech and used survey analysis methods to estimate seroprevalence accounting for the sampling design effect and test performance characteristics. Here we report results from the baseline (13 to 18 July 2020) and the first month of follow-up (13 to 18 August 2020) study.FindingsWe enrolled a total of 716 participants and estimated seroprevalence of 70.0% (95% CI: 67.0%–73.4%), a test-re-test positivity of 65% (95% CI: 61.0%–68.3%), and an incidence of new exposures of 1.8% (95% CI: 0.9%–3.2%) data that suggest that transmission is ongoing but is occurring at low levels. We observed significant differences in the seroprevalence between age groups, with participants 18 to 29 years of age having lower seroprevalence than children <12 years of age (Prevalence ratio =0.85 [PR]; 95% CI: 0.73 – 0.98), suggesting that children were not refractory to infection in this setting.InterpretationIquitos demonstrates one of the highest rates of seroprevalence of COVID-19 worldwide. Current data shows a limited case burden in Iquitos for the past seven months and suggests that these levels are sufficient to provide significant but incomplete herd immunity.FundingDirección Regional de Salud de Loreto, DIRESA, Loreto, Peru

scholarly journals Enzyme immunoassay for SARS-CoV-2 antibodies in dried blood spot samples: A minimally-invasive approach to facilitate community- and population-based screening

2020 ◽  
Author(s):  
Thomas W. McDade ◽  
Elizabeth M. McNally ◽  
Richard D’Aquila ◽  
Brian Mustanski ◽  
Aaron Miller ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Venous Blood ◽  
Population Based ◽  
Dried Blood Spot ◽  
Molecular Diagnostic ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Testing ◽  
Igg Antibodies ◽  
Wide Range ◽  
Blood Spot

AbstractBackgroundSerological testing for SARS-CoV-2 IgG antibodies is needed to document the community prevalence and distribution of the virus, particularly since many individuals have mild symptoms and cannot access molecular diagnostic testing of naso-pharyngeal swabs. However, the requirement for serum/plasma limits serological testing to clinical settings where it is feasible to collect and process venous blood. To address this problem we developed a serological test for SARS-CoV-2 IgG antibodies that requires only a single drop of capillary whole blood, collected from a simple finger prick and dried on filter paper (dried blood spot, DBS).MethodsEnzyme linked immunosorbent assay (ELISA) was optimized to detect SARS-CoV-2 IgG antibodies against the receptor-binding domain (RBD) of the spike protein. DBS samples were eluted overnight and transferred to a 96-well plate coated with antigen, and anti-human IgG-HRP was used to generate signal in proportion to bound antibody. DBS samples spiked with anti-SARS IgG antibody, and samples from known positive and negative cases, were compared to evaluate assay performance.ResultsAnalysis of samples with known concentrations of anti-SARS IgG produced the expected pattern of dose-response. Optical density (OD) values were significantly elevated for known positive cases in comparison with samples from unexposed individuals.DiscussionDBS ELISA provides a minimally-invasive alternative to venous blood collection that combines the convenience of sample collection in the home or non-clinical setting with the quantitation of ELISA in the lab. Serological testing for SARS-CoV-2 IgG antibodies in DBS samples should facilitate research across a wide range of community- and population-based settings on seroprevalence, predictors and duration of antibody responses, as well as correlates of protection from reinfection, each of which is critically important for pandemic control.

Adult systemic lupus erythematosus in Egypt: The nation-wide spectrum of 3661 patients and world-wide standpoint

Lupus ◽  
2021 ◽  
pp. 096120332110142
Author(s):  
Tamer A Gheita ◽  
Rasha Abdel Noor ◽  
Esam Abualfadl ◽  
Osama S Abousehly ◽  
Iman I El-Gazzar ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Age Of Onset ◽  
Wide Spectrum ◽  
Age At Onset ◽  
Disease Onset ◽  
Clinical Manifestations ◽  
Population Based ◽  
Systemic Lupus ◽  
Cross Sectional

Objective The aim of this study was to present the epidemiology, clinical manifestations and treatment pattern of systemic lupus erythematosus (SLE) in Egyptian patients over the country and compare the findings to large cohorts worldwide. Objectives were extended to focus on the age at onset and gender driven influence on the disease characteristics. Patients and method This population-based, multicenter, cross-sectional study included 3661 adult SLE patients from Egyptian rheumatology departments across the nation. Demographic, clinical, and therapeutic data were assessed for all patients. Results The study included 3661 patients; 3296 females and 365 males (9.03:1) and the median age was 30 years (17–79 years), disease duration 4 years (0–75 years) while the median age at disease onset was 25 years (4–75 years). The overall estimated prevalence of adult SLE in Egypt was 6.1/100,000 population (1.2/100,000 males and 11.3/100,000 females).There were 316 (8.6%) juvenile-onset (Jo-SLE) and 3345 adult-onset (Ao-SLE). Age at onset was highest in South and lowest in Cairo (p < 0.0001). Conclusion SLE in Egypt had a wide variety of clinical and immunological manifestations, with some similarities with that in other nations and differences within the same country. The clinical characteristics, autoantibodies and comorbidities are comparable between Ao-SLE and Jo-SLE. The frequency of various clinical and immunological manifestations varied between gender. Additional studies are needed to determine the underlying factors contributing to gender and age of onset differences.

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

Vaccines ◽  
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.

scholarly journals Multicentre Evaluation of Hepika Test Clinical Accuracy in Diagnosing HPV-Induced Cancer and Precancerous Lesions of the Uterine Cervix

Diagnostics ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 619
Author(s):  
Daniela Gustinucci ◽  
Lucia Ciccocioppo ◽  
Luigi Coppola ◽  
Giovanni Negri ◽  
Gianfranco Zannoni ◽  
...  
Keyword(s):  
Uterine Cervix ◽  
Protein Complexes ◽  
Precancerous Lesions ◽  
Intraepithelial Neoplasia ◽  
Population Based ◽  
Enzyme Linked Immunosorbent Assay ◽  
Lower Sensitivity ◽  
Adenocarcinoma In Situ ◽  
Clinical Accuracy ◽  
Grade 3

Objective: To evaluate the clinical accuracy of Hepika test to identify cancer/precancerous lesions of the uterine cervix. Materials and Methods: A multicentre retrospective study was carried out in 2018 and included 330 liquid-based cytology samples from three Italian centres of women aged 25–64 who had been tested for the human papillomavirus (HPV) and whose histology or follow-up outcome was known. Hepika is an enzyme-linked immunosorbent assay (ELISA) targeting the protein complexes E6#p53 and E7#pRb. After excluding samples without sufficient residual material, the clinical accuracy of Hepika test was evaluated in 274 samples: adenocarcinoma (ADC) (4), squamous cell carcinoma (SCC) (7), adenocarcinoma in situ (AIS) (1), cervical intraepithelial neoplasia (CIN) grade 3 (60), CIN2 (51), CIN1 (34), and negative histology (117). Association, sensitivity, and specificity for carcinoma, CIN3+ and CIN2+ are reported. Results: Positive Hepika test was associated with a high probability of carcinoma (odds ratio (DOR) = 33.68, 95% confidence interval (CI) 7.0–163.1); sensitivity was 81.8%, specificity, 88.2%. A positive Hepika test showed a weaker association with CIN3+ lesions (DOR = 3.5; 95% CI 1.75–6.99) and lower sensitivity (27.8%). Conclusion: The Hepika test was found to be an accurate biomarker for HPV-induced cervical carcinoma. Population-based prospective studies are needed to confirm the clinical usefulness of the Hepika test in the differential diagnosis of HPV-induced invasive lesions.

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