A Low-Cost SARS-CoV-2 rRBD ELISA to Detect Serostatus in Ecuadorian Population with COVID-19

Guevara, Ángel; Vivero, Sandra; Nipáz, Victoria; Guaraca, Victor; Coloma, Joséfina

doi:10.4269/ajtmh.20-1420

Cited by 6 publications

(6 citation statements)

References 5 publications

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“…Additionally, we determine the presence of SARS-CoV-2 specific IgG antibodies in those participants with an "in-house" ELISA (Amanat et al, 2020, Guevara et al, 2021. We show that a significant percentage of unexposed donors possess SARS-CoV-2 reactive T-cells, and we discuss these results.…”

Section: Introductionmentioning

confidence: 92%

Pre-existing T-cell immunity to SARS-CoV-2 in unexposed healthy controls in Ecuador, as detected with a COVID-19 Interferon-Gamma Release Assay

Echeverría

Guevara

Coloma

et al. 2021

International Journal of Infectious Diseases

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Background Studies of T-cell immune responses against SARS-CoV-2 are important in understanding the immune status of individuals or populations. Here, we use a simple, cheap and rapid whole blood stimulation assay - an Interferon-Gamma Release Assay (IGRA) - to study T-cell immunity to SARS-CoV-2 in convalescent COVID-19 patients and in unexposed healthy contacts from Quito, Ecuador. Methods Interferon-gamma (INF-γ) production was measured in the heparinized blood of convalescent and unexposed subjects after stimulation for 24 hours with the SARS-CoV-2 Spike S1 protein, the Receptor Binding Domain (RBD) protein or the Nucleocapsid (NP) protein, respectively. The presence of IgG- RBD protein antibodies in both study groups was determined with an “in-house” ELISA. Results As measured with INF-γ production, 80% of the convalescent COVID-19 patients, all IgG-RBD seropositive, had a strong T-cell response. However, unexpectedly, 44% of healthy unexposed healthy controls, all IgG-RBD seronegative, had a strong virus-specific T-cell response with the COVID-19 IGRA, probably because of prior exposure to common cold-causing coronaviruses or other viral or microbial antigens. Conclusion and Discussion The high percentage of unexposed healthy subjects with a pre-existing immunity suggests that a part of the Ecuadorian population is likely to have SARS-CoV-2 reactive T cells. Given that the IGRA technique is simple, and can be easily scaled up for investigations where high numbers of patients are needed, this COVID-19 IGRA may serve to determine if the T-cell only response represents protective immunity to SARS-CoV-2 infection in a population-based study.

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Section: Introductionmentioning

confidence: 92%

Pre-existing T-cell immunity to SARS-CoV-2 in unexposed healthy controls in Ecuador, as detected with a COVID-19 Interferon-Gamma Release Assay

Echeverría

Guevara

Coloma

et al. 2021

International Journal of Infectious Diseases

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“…For IgG detection, sensitivity ranged from 76.31-94.7%, while IgM detection displayed more variability, ranging from 47.0-81.6%. However, all studies consistently achieved high specificities above 95% [24] , [25] , [26] , [27] , [28] , [29] . In one study, immunoassay accuracy using RBD for IgG detection reached 94.0%, surpassing our study's results [29] .…”

Section: Discussionmentioning

confidence: 86%

Usefulness of receptor binding domain protein-based serodiagnosis of COVID-19

Vasconcelos,

Leony,

Camelier

et al. 2024

IJID Regions

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“…After centrifugation, plasma is stored at −20°C until analysis. Levels of IgG specific for SARS-CoV-2 are being measured using a validated enzyme linked immunosorbent assay 55…”

Section: Methods and Analysismentioning

confidence: 99%

“…Levels of IgG specific for SARS-CoV-2 are being measured using a validated enzyme linked immunosorbent assay. 55 …”

Section: Methods and Analysismentioning

confidence: 99%

Prospective study of factors associated with asthma attack recurrence (ATTACK) in children from three Ecuadorian cities during COVID-19: a study protocol

et al. 2022

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IntroductionAsthma is a growing health problem in children in marginalised urban settings in low-income and middle-income countries. Asthma attacks are an important cause of emergency care attendance and long-term morbidity. We designed a prospective study, the Asthma Attacks study, to identify factors associated with recurrence of asthma attacks (or exacerbations) among children and adolescents attending emergency care in three Ecuadorian cities.Methods and analysisProspective cohort study designed to identify risk factors associated with recurrence of asthma attacks in 450 children and adolescents aged 5–17 years attending emergency care in public hospitals in three Ecuadorian cities (Quito, Cuenca and Portoviejo). The primary outcome will be rate of asthma attack recurrence during up to 12 months of follow-up. Data are being collected at baseline and during follow-up by questionnaire: sociodemographic data, asthma history and management (baseline only); recurrence of asthma symptoms and attacks (monthly); economic costs of asthma to family; Asthma Control Test; Pediatric Asthma Quality of life Questionnaire; and Newcastle Asthma Knowledge Questionnaire (baseline only). In addition, the following are being measured at baseline and during follow-up: lung function and reversibility by spirometry before and after salbutamol; fractional exhaled nitric oxide (FeNO); and presence of IgG antibodies to SARS-CoV-2 in blood. Recruitment started in 2019 but because of severe disruption to emergency services caused by the COVID-19 pandemic, eligibility criteria were modified to include asthmatic children with uncontrolled symptoms and registered with collaborating hospitals. Data will be analysed using logistic regression and survival analyses.Ethics and disseminationEthical approval was obtained from the Hospital General Docente de Calderon (CEISH-HGDC 2019-001) and Ecuadorian Ministry of Public Health (MSP-CGDES-2021-0041-O N° 096-2021). The study results will be disseminated through presentations at conferences and to key stakeholder groups including policy-makers, postgraduate theses, peer-review publications and a study website. Participants gave informed consent to participate in the study before taking part.

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A Low-Cost SARS-CoV-2 rRBD ELISA to Detect Serostatus in Ecuadorian Population with COVID-19

Cited by 6 publications

References 5 publications

Pre-existing T-cell immunity to SARS-CoV-2 in unexposed healthy controls in Ecuador, as detected with a COVID-19 Interferon-Gamma Release Assay

Pre-existing T-cell immunity to SARS-CoV-2 in unexposed healthy controls in Ecuador, as detected with a COVID-19 Interferon-Gamma Release Assay

Usefulness of receptor binding domain protein-based serodiagnosis of COVID-19

Prospective study of factors associated with asthma attack recurrence (ATTACK) in children from three Ecuadorian cities during COVID-19: a study protocol

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