This study is testing a vaccine called RSVpreF to see if it can help prevent a lung disease called LRTI-RSV, which is caused by a virus. LRTI-RSV stands for Lower Respiratory Tract Infection caused by the Respiratory Syncytial Virus. The study involves adults aged 60 and over and will take place in several countries, including the United States, Canada, and Argentina. Participants will receive one or two doses of the vaccine or a placebo (a harmless substance that looks like the vaccine) and will be monitored for up to 24 months.

• Each participant's involvement could last up to 24 months.
• Participants will have regular check-ups and blood tests.
• This study is only for healthy adults aged 60 and older.

Researchers want to ensure the vaccine is safe, effective, and helps the body create antibodies (proteins that fight off the virus). Participants need to be generally healthy and willing to follow study procedures, like attending scheduled visits and providing samples.