RecruitingVaccine Responses to SARS-CoV-2 and Other Emerging Infectious DiseasesBackground: Vaccines against SARS-CoV-2, the virus that causes COVID-19, have been highly effective against preventing severe disease. But the protective effects of these vaccines appear to wane over time. Researchers want to learn why. Objective: To learn more about how the immune system responds to vaccines against infections like SARS-CoV-2. Eligibility: Healthy adults ages 18 or older who are scheduled to receive either a new vaccine or a booster shot against SARS-COV-2 or another emerging infection. Design: Participants will be screened with a medical history and blood and urine tests. Participants will have up to 8 study visits in 1 year. Each visit should last less than 2 hours. At each visit, participants will give blood samples. Some blood samples will be used for genetic testing. They will also give updates on their health. After the first study visit, participants will receive either a first vaccination or a booster shot. They must get the vaccine in their community or workplace. They will not get the vaccine at NIH. This study currently focuses on SARS-CoV-2, but it will expand to other infectious diseases as they emerge and become the target of new vaccines. ...