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Time-Dependent Decay of Detectable Antibodies Against SARS-CoV-2: A Comparison of ELISA with Two Batches of a Lateral-Flow Test

11 Pages Posted: 22 Jan 2021

See all articles by Mariangela Freitas Silveira

Mariangela Freitas Silveira

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology

Marilia Mesenburg

Federal University of Pelotas (UFPel)

Odir Antonio Dellagostin

Universidade Federal de Pelotas

Natasha R. Oliveira

Universidade Federal de Pelotas

Mara Andrade Colares Maia

Universidade Federal de Pelotas

Francisco Denis Souza Santos

Universidade Federal de Pelotas

Andre M. Vale

Universidade Federal do Rio de Janeiro (UFRJ) - Program in Immunobiology

Aluisio Barros

Federal University of Pelotas (UFPel) - International Center for Equity in Health (ICEH)

Luis Paulo Vidaletti

Federal University of Pelotas (UFPel) - International Center for Equity in Health (ICEH)

Fernando C. Barros

Universidade Católica de Pelotas; Federal University of Pelotas (UFPel)

Pedro C. Hallal

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology

Bernardo Lessa Horta

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology

Ana M. B. Menezes

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology

Gabriel D. Victora

Universidade Federal de Pelotas

Cesar G. Victora

Federal University of Pelotas (UFPel) - International Center for Equity in Health (ICEH); Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology

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Abstract

Background: Large-scale epidemiological studies of seroprevalence of antibodies against SARS-CoV-2 often rely on point-of-care tests that provide immediate results to participants. Yet, little is known on how long rapid tests remain positive after the COVID-19 episode, or how much variability exists across different brands and even among batches of the same test.

Methods: In November 2020, we assessed the sensitivity of three tests applied to 133 individuals with a previous positive PCR result between April and October. All subjects provided finger prick blood samples for two batches (A and B) of the Wondfo lateral-flow IgG/IgM test, and dried blood spot samples for the S-UFRJ ELISA test.

Results: Overall sensitivity levels were 92.5% (95% CI 86.6;96.3), 63.2% (54.4;71.4) and 33.8% (25.9;42.5) for the S-UFRJ test, Wondfo A and Wondfo B tests. There was no evidence of a decline in the positivity of S-UFRJ with time since the diagnosis, but the two Wondfo batches showed sharp reductions to as low as 41.9% and 19.4%, respectively, for subjects with a positive PCR in June or earlier. Positive results for batch B of the rapid test were 35% to 54% lower than for batch A at any given month of diagnosis.

Interpretation: Whereas the ELISA test showed high sensitivity and stability of results over the five months of the study, both batches of the rapid test showed substantial declines, with one of the batches consistently showing lower sensitivity levels than the other.  ELISA tests based on dried-blood spots are an inexpensive alternative to rapid lateral-flow tests in large-scale epidemiological studies.

Funding: The study was funded by the “Todos Pela Saúde” initiative, Instituto Serrapilheira, Brazilian Ministry of Health, Brazilian Collective Health Association (ABRASCO) and the JBS S.A. initiative ‘Fazer o Bem Faz Bem’.

Declaration of Interests: None to Declare

Ethics Approval Statement: Ethical approval by the Brazilian National Ethics Committee (process number 30415520.2.0000.5313).

Suggested Citation

Silveira, Mariangela Freitas and Mesenburg, Marilia and Dellagostin, Odir Antonio and Oliveira, Natasha R. and Maia, Mara Andrade Colares and Santos, Francisco Denis Souza and Vale, Andre M. and Barros, Aluisio and Vidaletti, Luis Paulo and Barros, Fernando C. and Hallal, Pedro C. and Lessa Horta, Bernardo and Menezes, Ana M. B. and Victora, Gabriel D. and Victora, Cesar G., Time-Dependent Decay of Detectable Antibodies Against SARS-CoV-2: A Comparison of ELISA with Two Batches of a Lateral-Flow Test. Available at SSRN: https://ssrn.com/abstract=3757411 or http://dx.doi.org/10.2139/ssrn.3757411

Mariangela Freitas Silveira

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology

Brazil

Marilia Mesenburg (Contact Author)

Federal University of Pelotas (UFPel) ( email )

Pelotas, Rio Grande do Sul, RS
Brazil

Odir Antonio Dellagostin

Universidade Federal de Pelotas ( email )

Natasha R. Oliveira

Universidade Federal de Pelotas ( email )

Mara Andrade Colares Maia

Universidade Federal de Pelotas ( email )

Francisco Denis Souza Santos

Universidade Federal de Pelotas ( email )

Andre M. Vale

Universidade Federal do Rio de Janeiro (UFRJ) - Program in Immunobiology ( email )

Rio de Janiero
Brazil

Aluisio Barros

Federal University of Pelotas (UFPel) - International Center for Equity in Health (ICEH) ( email )

Brazil

Luis Paulo Vidaletti

Federal University of Pelotas (UFPel) - International Center for Equity in Health (ICEH) ( email )

Fernando C. Barros

Universidade Católica de Pelotas ( email )

Federal University of Pelotas (UFPel) ( email )

Pedro C. Hallal

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology

Brazil

Bernardo Lessa Horta

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology ( email )

Rua Marechal Deodoro, 1160 - 3° Piso
Pelotas
Brazil

Ana M. B. Menezes

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology ( email )

Gabriel D. Victora

Universidade Federal de Pelotas ( email )

Cesar G. Victora

Federal University of Pelotas (UFPel) - International Center for Equity in Health (ICEH) ( email )

Brazil

Federal University of Pelotas (UFPel) - Postgraduate Program in Epidemiology ( email )

Brazil