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

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

Estimated SARS-CoV-2 Infection and Seroprevalence in Firefighters from a Northeastern Brazilian State: A Cross-Sectional Study

The new coronavirus has been affecting health worldwide and essential service workers are continually exposed to this infectious agent, increasing the chance of infection and the development of the disease. Thus, this study aimed to estimate the frequency of infection and seroprevalence for SARS-CoV-2 in military firefighters in a city in Northeastern Brazil in January 2021. An observational cross-sectional study was carried out with 123 firefighters who answered a brief questionnaire to collect socio-epidemiological data and underwent RT-PCR and immunofluorescence test (IgM and IgG). The results found reveal a positive seroprevalence, with a high rate of infection in this class of workers, since they are essential service professionals who are exposed to risk due to their working hours, in addition to sharing some spaces and work materials. Besides, there were significant associations between positivity for IgG and IgM, as well as for positive RT-PCR prior to the study and the presence of IgG, with odd ratios of 3.04 and 4.9, respectively. These findings reinforce the need for immunization in this category, whose line of service hinders the adoption of distancing measures, since in many situations physical contact is inevitable

Evolutionary dynamics and dissemination pattern of the SARS-CoV-2 lineage B.1.1.33 during the early pandemic phase in Brazil

We would like to thank the funding support from CGLab/MoH (General Laboratories Coordination of Brazilian Ministry of Health), CVSLR/FIOCRUZ (Coordination of Health Surveillance and Reference Laboratories of Oswaldo Cruz Foundation), CNPq COVID-19 MCTI 402457/2020-0, and INOVA VPPCB-005-FIO20-2Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.Universidade Federal do Espírito Santo - Campus de Alegre. Centro de Ciências Exatas, Naturais e da Saude. Departamento de Biologia. Vitória, ES, Brazil.Fundação Oswaldo Cruz. Gonçalo Moniz. Salvador, BA, Brazil.Universidad de la Republica. Centro Universitario Regional del Litoral Norte. Unidad de Genomica y Bioinformatica. Salto, Uruguay.Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhaes. Recife, PE, Brazil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhaes. Recife, PE, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Laboratorio Central de Saude Publica do Estado de Santa Catarina. Florianopolis, SC, Brazil.Laboratorio Central de Saude Publica do Estado Espirito Santo. Vitoria, ES, Brazil.Laboratorio Central de Saude Publica do Distrito Federal. Brasília, DF, Brazil.Laboratorio Central de Saude Publica de Alagoas. Maceio, AL, Brazil.Laboratorio Central de Saude Publica da Bahia. Salvador, BA, Brazil.Laboratorio Central de Saude Publica de Sergipe. Aracaju, SE, Brazil.Laboratorio Central de Saude Publica de Parana. Curitiba, PR, Brazil.Laboratorio Central de Saude Publica de Parana. Curitiba, PR, Brazil.Fundação Oswaldo Cuz - Mato Grosso do Sul. Campo Grande, MT, Brazil / Universidade Federal de Mato Grosso do Sul. Campo Grande, MT, Brazil.Ministério da Defesa. Hospital das Forças Armadas. Brasília, DF, Brazil.Ministério da Saude. Coordenadoria Geral de Laboratorios. Brasília, DF, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratorio de AIDS e Imunologia Molecular. Rio de Janeiro, RJ, Brazil.Oswaldo Cruz Foundation. Oswaldo Cruz Institute. Laboratory of Respiratory Viruses and Measles. Rio de Janeiro, RJ, Brasil / Brazilian Ministry of Health. Pan-American Health Organization. SARS-CoV-2 National Reference Laboratory. Regional Reference Laboratory in Americas. Rio de Janeiro, RJ, Brazil.A previous study demonstrates that most of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Brazilian strains fell in three local clades that were introduced from Europe around late February 2020. Here we investigated in more detail the origin of the major and most widely disseminated SARS-CoV-2 Brazilian lineage B.1.1.33. We recovered 190 whole viral genomes collected from 13 Brazilian states from February 29 to April 31, 2020 and combined them with other B.1.1 genomes collected globally. Our genomic survey confirms that lineage B.1.1.33 is responsible for a variable fraction of the community viral transmissions in Brazilian states, ranging from 2% of all SARS-CoV-2 genomes from Pernambuco to 80% of those from Rio de Janeiro. We detected a moderate prevalence (5-18%) of lineage B.1.1.33 in some South American countries and a very low prevalence (<1%) in North America, Europe, and Oceania. Our study reveals that lineage B.1.1.33 evolved from an ancestral clade, here designated B.1.1.33-like, that carries one of the two B.1.1.33 synapomorphic mutations. The B.1.1.33-like lineage may have been introduced from Europe or arose in Brazil in early February 2020 and a few weeks later gave origin to the lineage B.1.1.33. These SARS-CoV-2 lineages probably circulated during February 2020 and reached all Brazilian regions and multiple countries around the world by mid-March, before the implementation of air travel restrictions in Brazil. Our phylodynamic analysis also indicates that public health interventions were partially effective to control the expansion of lineage B.1.1.33 in Rio de Janeiro because its median effective reproductive number (R e ) was drastically reduced by about 66% during March 2020, but failed to bring it to below one. Continuous genomic surveillance of lineage B.1.1.33 might provide valuable information about epidemic dynamics and the effectiveness of public health interventions in some Brazilian states

Increased interregional virus exchange and nucleotide diversity outline the expansion of chikungunya virus in Brazil

Abstract The emergence and reemergence of mosquito-borne diseases in Brazil such as yellow fever, zika, chikungunya, and dengue have had serious impacts on public health. Concerns have been raised due to the rapid dissemination of the chikungunya virus across the country since its first detection in 2014 in Northeast Brazil. In this work, we carried out on-site training activities in genomic surveillance in partnership with the National Network of Public Health Laboratories that have led to the generation of 422 chikungunya virus genomes from 12 Brazilian states over the past two years (2021–2022), a period that has seen more than 312 thousand chikungunya fever cases reported in the country. These genomes increased the amount of available data and allowed a more comprehensive characterization of the dispersal dynamics of the chikungunya virus East-Central-South-African lineage in Brazil. Tree branching patterns revealed the emergence and expansion of two distinct subclades. Phylogeographic analysis indicated that the northeast region has been the leading hub of virus spread towards other regions. Increased frequency of C > T transitions among the new genomes suggested that host restriction factors from the immune system such as ADAR and AID/APOBEC deaminases might be driving the genetic diversity of the chikungunya virus in Brazil