Additional Study Information: The purpose of this study is to assess the effectiveness of influenza and SARS-CoV-2 vaccines for preventing transmission of infections in households. We are seeking volunteers who have been recently diagnosed with COVID-19 or Influenza virus infection by either rapid diagnostic assay or RT-PCR in the last 7 days and live in a household with at least one other person. The study, also known as RVTN Sentinel Respiratory VirusTransmission Network will be looking at household transmission of SARS-CoV-2 and/or influenza. Once someone and their household contacts are enrolled, they will be followed for 10 consecutive days to identify new viruses infections among household members. Follow-up will include interviews/questionnaires, self-collection of a fingerstick of blood for the person who tested positive, daily data collection from all participating household members for 10 days, daily self-collected nasal swabs from all participating household members, remote video/telephone visits during the follow-up period, and an option self-collection of a blood specimen 46 weeks after enrollment. All study visits will be remote ie no one has to come to the medical center. Households will be compensated up to $250.