A Study to Learn Safety and Immune Response to Study Vaccine -RSVpreF in Adults at High Risk of Severe RSV Disease.

The purpose of the study is to learn about the immune response after a RSVpreF vaccination. This study is being conducted in Japan. RSV is a common virus that can cause infections of the lungs and airways. The study is seeking participants who are: * 18 to 59 years of age * adults with health condition(s) that can put them at an increased risk of severe RSV disease It will also learn about the safety of RSVpreF vaccination. The study lasts about 2 months. Adults need to visit the research site at least 2 times. The participant will receive a phone call 2 months after vaccination for health checks.

NCT Number	NCT07543380
Lead Sponsor	Pfizer
Conditions	Respiratory Syncytial Virus (RSV)
Enrollment	130 participants
Start Date	2026-05-11
Primary Completion	2026-08-31 (estimated)
Study Completion	2026-08-31 (estimated)
Updated on ClinicalTrials.gov	2026-06-02