Tracking the community-wide spread of SARS-CoV-2: outbreak size, transmission dynamics, clinical outcomes of infection, and duration of naturally acquired antibody responses in an Amazonian town

Abstract

SARS-CoV-2 has now spread globally and poses a major challenge for low- and middle-income countries, where local health infrastructure can be quickly overwhelmed. This proposal builds upon ongoing, FAPESP-supported field research to address the microepidemiology and control of SARS-CoV-2 infection in Mâncio Lima, an urban community in the Amazon. The overarching goal is translating field-collected data into evidence to guide COVID-19 control in one of the poorest regions of Brazil. We hypothesize that a large proportion of local SARS-CoV-2 infections will go unnoticed, and apparently healthy virus carriers may continue spreading the infection through their routine social interactions but will eventually eliminate the pathogen and become immune to reinfection or at least to severe COVID-19. To test this hypothesis, we will: (a) use serial antibody assays to detect seroconversion events, retrospectively estimate the SARS-CoV-2 outbreak size and identify risk factors associated with seroconversion; (b) identify personal interactions and shared spaces, such as the household, workplace, schools, and churches, that have contributed the most to SARS-CoV-2 transmission; (c) estimate the proportion of SARS-CoV-2 infections with mild or no symptoms, which remained undiagnosed, and the proportion of those leading to clinically manifest COVID-19, resulting in health facility visits and even hospitalization, and (d) determine the proportion of individuals found to be seropositive shortly after the outbreak that will have detectable anti-SARS-CoV-2 antibodies up to one year later. (AU)