The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was declared a Public Health Emergency of International Concern in January 2020 and upgraded to pandemic in March 2020. First vaccines to prevent COVID-19 were authorized for emergency use in the US in December 2020, but a number of unknowns still remains. One of these unknowns is the relationship of the microbiota, gut dysbiosis and impaired metabolism with active immunity to pathogens and vaccines and tolerance to antigens. Study groups will be based on age, metabolism, donated diagnostic test results and self-reported symptoms. Data will be collected continuously via surveys and investigator-participant interactions, as needed. Statistical methods used will be the ones with the greatest power.