Cross-sectional analysis of students and school workers reveals a high number of asymptomatic SARS-CoV-2 infections during school reopening in Brazilian cities

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Borges, Lysandro P. ; Guimaraes, Adriana G. ; Fonseca, Dennyson Leandro M. ; Freire, Paula P. ; Barreto, Ikaro D. C. ; Souza, Daniela R., V ; Gurgel, Ricardo Q. ; Lopes, Aline S. A. ; de Rezende Neto, Jose Melquiades ; dos Santos, Kezia A. ; Matos, Igor L. S. ; da Invencao, Grazielly B. ; Oliveira, Brenda M. ; Santos, Aryanne A. ; Soares, Daniele Almeida ; de Jesus, Pamela C. ; dos Santos, Cliomar A. ; Goes, Marco A. O. ; Placa, Desiree Rodrigues ; Filgueiras, Igor Salerno ; Marques, Alexandre H. C. ; Baiocchi, Gabriela Crispim ; Cabral-Miranda, William ; de Miranda, Gustavo Cabral ; Saraiva Camara, Niels Olsen ; Calich, Vera Lucia Garcia ; Ramos, Rodrigo Nalio ; Nakaya, Helder, I ; Rocha, Vanderson ; Giil, Lasse M. ; Ochs, Hans D. ; Schimke, Lena F. ; de Souza, Mercia S. F. ; Cuevas, Luis E. ; Martins, Aline F. ; Cabral-Marques, Otavio

• Document type: Journal article
• Source: HELIYON; v. 8, n. 11, p. 11-pg., 2022-11-07.

Abstract

Brazil experienced one of the most prolonged periods of school closures, and reopening could have exposed students to high rates of SARS-CoV-2 infection. However, the infection status of students and school workers at the time of the reopening of schools located in Brazilian cities is unknown. Here we evaluated viral carriage by RT-PCR and seroprevalence of anti-SARS-CoV-2 antibodies (IgM and IgG) by immunochromatography in 2259 individuals (1139 students and 1120 school workers) from 28 schools in 28 Brazilian cities. We collected the samples within 30 days after public schools reopened and before the start of vaccination campaigns. Most students (n = 421) and school workers (n = 446) had active (qRT-PCR + IgM- IgG-or qRT-PCR + IgM + IgG-/+) SARS-CoV-2 infection. Regression analysis indicated a strong association between the infection status of students and school workers. Furthermore, while 45% (n = 515) of the students and 37% (n = 415) of the school workers were neither antigen nor antibody positive in laboratory tests, 16% of the participants (169 students and 193 school workers) were oligosymptomatic, including those reinfected. These individuals presented mild symptoms such as headache, sore throat, and cough. Notably, most of the individuals were asymptomatic (83.9%). These results indicate that many SARS-CoV-2 infections in Brazilian cities during school reopening were asymptomatic. Thus, our study highlights the need to promote a coordinated public health effort to guarantee a safe educational environment while avoiding exacerbating pre-existent social inequalities in Brazil, reducing social, mental, and economic losses for students, school workers, and their families. (AU)

• FAPESP's process: 20/01688-0 - Systemic and integrative analysis of the immune response to Zika and Dengue viral infections
• Grantee: Otávio Cabral Marques
• Support Opportunities: Scholarships in Brazil - Young Researchers
• FAPESP's process: 18/18886-9 - Systemic and integrative analysis of the immune response to Zika and Dengue viral infections
• Grantee: Otávio Cabral Marques
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 20/09146-1 - Systemic and integrative analysis of molecular mechanisms associated with immunoregulation in patients with COVID-19
• Grantee: Paula Paccielli Freire-Barguil
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 20/07069-0 - Systemic and integrative analysis of T lymphocyte exhaustion mechanisms in patients with COVID-19
• Grantee: Otávio Cabral Marques
• Support Opportunities: Regular Research Grants