PROJECT SUMMARY/ABSTRACT SARS-COV-2, the virus that causes Coronavirus Disease (COVID) emerged in China in late 2019. It rapidly spread worldwide and is now causing a pandemic with high morbidity and mortality. Because SARS-COV-2 is a novel virus in humans, there are many fundamental knowledge gaps in our understanding of the virus and disease. To undertake a detailed investigation of SARS-COV-2 in Nicaragua, we propose to add on SARS-COV-2 aims to our existing Household Influenza Cohort Study. The research questions addressed build naturally on the infrastructure currently in place to conduct the Household Cohort Study. Specifically, we will add SARS-COV-2 testing on to samples that are already collected through our ongoing cohort study, add the collection of blood samples around SARS-COV-2 infection in participants, and perform a household SARS- COV-2 transmission study. This proposal addresses major gaps in knowledge on COVID natural history and transmission. It is thus timely and well-poised to have substantial public health and scientific impact.