A Study to Learn About Revaccination With a Vaccine Called RSVpreF in Older Adults

This study is testing the safety and tolerability of a second dose of Respiratory Syncytial Virus Vaccine (RSVpreF) given approximately 5 years after the initial dose.

Key Inclusion Criteria: * Must have participated in the previous Pfizer RSVpreF efficacy study (C3671013) and have been ≥60 years of age at the time of their enrollment in that study. * Must have received their initial RSVpreF dose in the C3671013 study about 5 years prior to enrollment in the current study (C3671087). * Must be determined to be in good health by the investigator, based on medical history and clinical judgment. Participants with stable chronic diseases (e.g., disease not requiring significant change in therapy or hospitalization for worsening disease during the 6 weeks before enrollment) are eligible. Key Exclusion Criteria: * History of a severe allergic reaction (e.g., anaphylaxis) to any component of the study intervention or any related vaccine. * History of Guillain-Barré Syndrome of any subtype or etiology. * Certain serious or unstable medical conditions that could increase the risks of study participation. * Previous vaccination with any other investigational or licensed RSV vaccine since receiving the initial dose in the C3671013 study. * Any medical or psychiatric condition that, in the investigator's judgment, would make the participant inappropriate for the study.