Additional Study Information: The main purpose of this study is to evaluate a Respiratory Syncytial Virus vaccine (RSVpreF for short). Respiratory Syncytial Virus, called RSV, is a common type of virus that is a major cause of respiratory infection in all ages, and can result in severe illness in those with health conditions that put them at increased risk of severe RSV and complications. We are doing a study to test the safety of the RSVpreF vaccine, and how well it is tolerated. The study will also test how a person's immune system responds to the vaccines and how much antibody is made after the vaccine. Approximately 60 people will participate at Columbia University Irving Medical Center. Participants must be at least 18 years of age to participate in this study. Participation in this study will last up to 9 months. You will be asked to come to the site at least 2 times and be available for at least 1 telephone contact. If you are part of the study, the following study procedures will take place: physical exam and vital signs, collection of medical history including any medicines you may be taking and vaccinations received, collection of symptoms in an electronic diary for 7 days, and collection of blood samples. You will be compensated for your time and travel.