Additional Study Information: This is a COVID transmission study happening across the US to help us learn whether the COVID-19 vaccine stops the spread of the SARS-CoV-2 virus (COVID): both initial infection and transmission to others. The answer to this question can have an important impact on all of our lives. Currently we are enrolling unvaccinated people. You will not be required to get vaccinated to participate in this study.Throughout the study period, all participants will complete questionnaires via an eDiary app and will be required to provide blood samples at a limited number of visits. In addition, study participants will be asked to collect daily nasal swabs that will be sent to a central laboratory for further analysis, enabling researchers to determine if infections occur, how much virus was present in the nose, and to perform genomic sequencing of the virus. Genomic sequencing will help demonstrate whether coronavirus variants play a role in the vaccines ability to prevent infection and transmission. Participants will only be notified of any positive COVID test results. You will be compensated for all study visits and for submitted swabs.