Revista de Saúde Pública (Oct 2021)

Prevalence evolution of SARS-CoV-2 infection in the city of São Paulo, 2020–2021

  • José Olimpio Moura de Albuquerque,
  • Gabriela Akemi Kamioka,
  • Geraldine Madalosso,
  • Selma Anequini Costa,
  • Paula Bisordi Ferreira,
  • Francisco Alberto Pino,
  • Ana Paula Sayuri Sato,
  • Ana Carolina Aguiar de Carvalho,
  • Ana Beatriz Pagliaro Amorim,
  • Caroline Cotrim Aires,
  • Ana Paula Arruda Geraldes Kataoka,
  • Elisa San Martin Mouriz Savani,
  • Thirsa Alvares Franco Bessa,
  • Breno Souza de Aguiar,
  • Marcelo Antunes Failla,
  • Edson Aparecido dos Santos,
  • Edjane Maria Torreão Brito,
  • Maria Cristina Honório dos Santos,
  • Solange Maria Saboia e Silva,
  • Luiz Artur Vieira Caldeira,
  • Luiz Carlos Zamarco,
  • Sandra Maria Sabino Fonseca,
  • Marcia Maria de Cerqueira Lima,
  • Ivanilda Argenau Marques,
  • Fabiana Érica Vilanova da Silva,
  • Paula Regina Glasser,
  • Patrícia Carla Piragibe Ramos Burihan,
  • Cinthya Luzia Cavazzana,
  • Debora Silva de Mello,
  • Alessandra Cristina Guedes Pellini,
  • Fernando Yoshiki Nishio,
  • Fernanda Miyashiro Kian,
  • Elza de Santana Braga,
  • Nilza Maria Piassi Bertelli,
  • Wagner Fracini,
  • Marcelo Dell Áquila Gonçalves,
  • Paulete Secco Zular,
  • Regiane de Santana Piva,
  • Eduardo Masi

DOI
https://doi.org/10.11606/s1518-8787.2021055003970
Journal volume & issue
Vol. 55

Abstract

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ABSTRACT OBJECTIVE To estimate the evolution of the prevalence of SARS-CoV-2 virus infection among residents aged 18 years or over in the municipality of São Paulo. METHODS This is a population-based household survey conducted every 15 days, between June and September 2020, and January and February 2021. In total, the study comprised 11 phases. The presence of antibodies against SARS-CoV-2 was identified in venous blood using a lateral flow test, Wondfo Biotech. In the last phase, the researchers combined it with an immunoenzymatic test, Euroimmun. The participants also answered a semi-structured questionnaire on sociodemographic and economic factors, and on social distancing measures. Prevalence estimates and the 95% confidence interval were estimated according to regions, Human Development Index, sex, age group, ethnicity, education, income, and variables associated with risk or prevention of infection. To compare the frequencies among the categories of each variable, the chi-square test with Rao-Scott correction was used, considering a significance level of 5%. RESULTS In total, 23,397 individuals were interviewed and had their samples collected. The estimated prevalence of antibodies against SARS-CoV-2 ranged from 9.7% (95%CI: 7.9–11.8%) to 25.0% (95%CI: 21.7–28.7). The prevalence of individuals with antibodies against the virus was higher among black and brown people, people with lower schooling and income, and among residents of regions with lower Human Development Index. The lowest prevalences were associated with recommended measures of disease protection. The proportion of asymptomatic infection was 45.1%. CONCLUSION The estimated prevalence of the infection was lower than the cumulative incidence variation, except for the last phase of the study. The differences in prevalence estimates observed among subpopulations showed social inequality as a risk of infection. The lower prevalence observed among those who could follow prevention measures reinforce the need to maintain social distancing measures as a way to prevent SARS-CoV-2 infection.

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