Population-level seropositivity trend for SARS-Cov-2 in Rio Grande do Sul, Brazil
DOI:
https://doi.org/10.11606/s1518-8787.2021055004075Keywords:
COVID-19, epidemiology, Seroepidemiologic Studies, Immunity, Herd, Socioeconomic Factors, Health SurveysAbstract
OBJECTIVE: To describe the evolution of seropositivity in the State of Rio Grande do Sul, Brazil, through 10 consecutive surveys conducted between April 2020 and April 2021. METHODS: Nine cities covering all regions of the State were studied, 500 households in each city. One resident in each household was randomly selected for testing. In survey rounds 1–8 we used the rapid WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech Co., Guangzhou, China). In rounds 9–10, we used a direct ELISA test that identifies IgG to the viral S protein (S-UFRJ). In terms of social distancing, individuals were asked three questions, from which we generated an exposure score using principal components analysis. RESULTS: Antibody prevalence in early April 2020 was 0.07%, increasing to 10.0% in February 2021, and to 18.2% in April 2021. In round 10, self-reported whites showed the lowest seroprevalence (17.3%), while indigenous individuals presented the highest (44.4%). Seropositivity increased by 40% when comparing the most with the least exposed. CONCLUSIONS: The proportion of the population already infected by SARS-Cov-2 in the state is still far from any perspective of herd immunity and the infection affects population groups in very different levels.
References
Chen X, Chen Z, Azman AS, Deng X, Sun R, Zhao Z, et al. Serological evidence of human infection with SARS-CoV-2: a systematic review and meta-analysis. Lancet Glob Health. 2021;9(5):e598-609. https://doi.org/10.1016/S2214-109X(21)00026-7
Gudbjartsson DF, Helgason A, Jonsson H, Magnusson OT, Melsted P, Norddahl GL, et al. Spread of SARS-CoV-2 in the Icelandic population. N Engl J Med. 2020;382(24):2302-15. https://doi.org/10.1056/NEJMoa2006100
Hofinger C, Ogris G. COVID-19 Prevalence. Vienna (CH): SORA Institute for Research and Consulting; 2020 [cited 2021 Jul 14]. Available from: https://www.sora.at/fileadmin/downloads/projekte/Austria_COVID-19_Prevalence_BMBWF_SORA_20200410_EN_Version.pdf
Gobierno de España, Ministerio de Ciencia e Innovación; Ministerio de Sanidad. Estudio ENE-COVID19: informe final. Estudio Nacional de Sero-Epidemiologia de la Infección por SARS-CoV-2 en España (6 de Julio de 2020). Madrid (ES); 2020 [cited 2021 Jul 14]. Available from: https://www.mscbs.gob.es/ciudadanos/ene-covid/docs/ESTUDIO_ENE-COVID19_INFORME_FINAL.pdf
Hallal PC, Hartwig FP, Horta BL, Silveira MF, Struchiner CJ, Vidaletti LP, et al. SARS-CoV-2 antibody prevalence in Brazil: results from two successive nationwide serological household surveys. Lancet Glob Health. 2020;8(11):E1390-8. https://doi.org/10.1016/S2214-109X(20)30387-9
Silva AAM, Lima-Neto LG, Azevedo CMPES, Costa LMM, Bragança MLBM, Barros Filho AKDB, et al. Population-based seroprevalence of SARS-CoV-2 is more than halfway through the herd immunity threshold in the State of Maranhão, Brazil. medRxiv [Preprint]. [posted 2020 Sept 1]. https://doi.org/10.1101/2020.08.28.20180463
Buss LF, Prete Jr CA, Abrahim CMM, Mendrone Jr A, Salomon T, Almeida-Neto C, et al. Three-quarters attack rate of SARS-CoV-2 in the Brazilian Amazon during a largely unmitigated epidemic. Science. 2021;371(6526):288-92. https://doi.org/10.1126/science.abe9728
Sabino EC, Buss LF, Carvalho MPS, Prete Jr CA, Crispim MAE, Fraiji NA, et al. Resurgence of COVID-19 in Manaus, Brazil, despite high seroprevalence. Lancet. 2021;397(10273):452-5. https://doi.org/10.1016/S0140-6736(21)00183-5
Sem vacina, “imunidade de rebanho” não é melhor estratégia, diz secretário do Ministério da Saúde. Folha S Paulo. 26 maio 2020. Available from: https://www1.folha.uol.com.br/cotidiano/2020/05/sem-vacina-imunidade-de-rebanho-nao-e-melhor-estrategia-diz-secretario-do-ministerio-da-saude.shtml
Hallal PC, Silveira MF, Menezes AMB, Horta BL, Barros AJD, Pellanda LC, et al. Slow spread of SARS-CoV-2 in Southern Brazil over a six-month period: report on eight sequential statewide serological surveys including 35,611 participants. Am J Public Health. 2021;111(8):1542-50. https://doi.org/10.2105/AJPH.2021.306351
Silveira MF, Mesenburg M, Dellagostin OA, Oliveira NR, Maia MAC, Santos FD, et al. Time-dependent decay of detectable antibodies against SARS-CoV-2: a comparison of ELISA with two batches of a lateral-flow test. SSRN. [Posted 2021 Jan 22]. https://doi.org/10.2139/ssrn.3757411
Alvim RGF, Lima TM, Rodrigues DAS, Marsili FF, Bozza VBT, Higa LM, et al. An affordable anti-SARS-COV-2 spike protein ELISA test for early detection of IgG seroconversion suited for large-scale surveillance studies in low-income countries. medRxiv [Preprint]. [posted 2020 Aug 2]. https://doi.org/10.1101/2020.07.13.20152884
Silveira MF, Barros AJD, Horta BL, Pellanda LC, Victora GD, Dellagostin AO, et al. Population-based surveys of antibodies against SARS-CoV-2 in Southern Brazil. Nat Med. 2020;26(8):1196-9. https://doi.org/10.1038/s41591-020-0992-3
Hartwig FP, Vidaletti LP, Barros AJD, Victora GD, Menezes AMB, Mesenburg MA, et al. Combining serological assays and official statistics to describe the trajectory of the COVID-19 pandemic: results from the EPICOVID19-RS study in Rio Grande do Sul (Southern Brazil). medRxiv [Preprint]. [posted 2021 May 24]. https://doi.org/10.1101/2021.05.21.21257634
Alvim RGF, Lima TM, Rodrigues DAS, Marsili FF, Bozza VBT, Higa LM, et al. An affordable anti-SARS-COV-2 spike protein ELISA test for early detection of IgG seroconversion suited for large-scale surveillance studies in low-income countries. SSRN [Preprint]. [posted 2020 Sept 17]. https://doi.org/10.2139/ssrn.3668433
Barros AJD, Victora CG. A nationwide wealth score based on the 2000 Brazilian demographic census. Rev Saude Publica. 2005;39(4):523-9. https://doi.org/10.1590/S0034-89102005000400002
Ewerling F, Barros AJD. After 10 years, how do changes in asset ownership affect the Indicador Econômico Nacional? Rev Saude Publica. 2017;51:10. https://doi.org/10.1590/S1518-8787.2017051006517
Filmer D, Pritchett LH. Estimating wealth effects without expenditure data-or tears: an application to educational enrollments in states of India. Demography. 2001;38(1):115-32. https://doi.org/10.1353/dem.2001.0003
Horta BL, Silveira MF, Barros AJD, Barros FC, Hartwig FP, Dias MS, et al. Prevalence of antibodies against SARS-CoV-2 according to socioeconomic and ethnic status in a nationwide Brazilian survey. Rev Panam Salud Publica. 2020;44:e135. https://doi.org/10.26633/RPSP.2020.135
Anderson RM, Vegvari C, Truscott J, Collyer BS. Challenges in creating herd immunity to SARS-CoV-2 infection by mass vaccination. Lancet. 2020;396(10263):1614-6. https://doi.org/10.1016/S0140-6736(20)32318-7
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Copyright (c) 2021 Aluísio J D Barros, Cesar G Victora, Ana M B Menezes, Bernardo L Horta, Fernando C Barros, Fernando P Hartwig, Gabriel D Victora, Luis Paulo Vidaletti, Mariângela F Silveira, Marilia A Mesenburg, Nadège Jacques, Cláudio J Struchiner, Flávia Roberta Brust, Marinel M Dall’Agnol, Ana Paula Longaray Delamare, Carlos Henrique R François, Maria Letícia R Ikeda, Débora C P Pellegrini, Cézane Priscila Reuter, Shana G da Silva, Odir A Dellagostin, Pedro C Hallal
This work is licensed under a Creative Commons Attribution 4.0 International License.
