Household Transmission and Immunity to SARS-CoV-2 among Paediatric Clients of a Primary Care Center in a Low-resource Community in Rio de Janeiro

This project aims to characterise household transmission dynamics in Manguinhos, an urban slum (favela), which has one of the lowest Human Development Index (HDI) scores of Rio de Janeiro/Brazil. We will also estimate the immunity of the study population against SARS-CoV-2. This will be a prospective study of household contacts of laboratory-confirmed SARS-CoV-2 infected and non-infected children and their families, following the WHO Household Transmission Investigation Protocol for COVID-19. We will recruit children 0 to 13 years of age who are brought to the local health care centre to receive free vaccinations. The clinic provides primary care to 4,300 children in this age group per month. After obtaining written informed consent from the child's guardian, samples will be collected at the clinic (oral fluid, nasopharyngeal and rectal swabs, and serum). The child's home will then be visited to collect samples from contacts. All samples will be screened for SARS-CoV-2 by PCR following the Charité protocol, and serum for IgG antibodies by ELISA or CLIA and for neutralising antibodies by FRNT. At the household we will collect samples at Days 1 (first visit), 14 and 28, every three months during the first year and twice in the second year. Clinical follow up will be done through telephone calls and video conferences by nurses and paediatricians from Day 0 to Day 28.