TY - JOUR
T1 - Population-level seropositivity trend for SARS-Cov-2 in Rio Grande do Sul, Brazil
AU - Barros, Aluísio J.D.
AU - Victora, Cesar G.
AU - Menezes, Ana M.B.
AU - Horta, Bernardo L.
AU - Barros, Fernando C.
AU - Hartwig, Fernando P.
AU - Victora, Gabriel D.
AU - Vidaletti, Luis Paulo
AU - Silveira, Mariângela F.
AU - Mesenburg, Marilia A.
AU - Jacques, Nadège
AU - Struchiner, Cláudio J.
AU - Brust, Flávia Roberta
AU - Dall'Agnol, Marinel M.
AU - Delamare, Ana Paula Longaray
AU - François, Carlos Henrique R.
AU - Ikeda, Maria Letícia R.
AU - Pellegrini, Débora C.P.
AU - Reuter, Cézane Priscila
AU - da Silva, Shana G.
AU - Dellagostin, Odir A.
AU - Hallal, Pedro C.
N1 - Publisher Copyright:
© 2021. All Rights Reserved.
PY - 2021
Y1 - 2021
N2 - 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.
AB - 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.
KW - COVID-19
KW - epidemiology
KW - Health Surveys
KW - Herd
KW - Immunity
KW - Seroepidemiologic Studies
KW - Socioeconomic Factors
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U2 - 10.11606/s1518-8787.2021055004075
DO - 10.11606/s1518-8787.2021055004075
M3 - Article
AN - SCOPUS:85124937162
SN - 0034-8910
VL - 55
JO - Revista de saude publica
JF - Revista de saude publica
M1 - 78
ER -