Eligibility requirements

• Age: 60-85 yrs inclusive
• Sex: M & F
• Medication: Inclusions (but are not limited to): 60 to 85 years old at the screening visit. Willing and able to give written consent. Willing and able to attend all study visits and follow study procedures. Generally healthy, or with stable medical conditions (no major changes or hospital stays in the past 3 months). Females must not be able to become pregnant (e.g. should be postmenopausal, be surgically sterile or use effective contraception). Negative pregnancy test on the day of vaccination. Males must not donate sperm for 90 days after vaccination. Agreement not to donate blood during the study.
• Medical History: Exclusions include but are not limited to: Pregnant or capable of becoming pregnant (e.g. period in the last 12 months or fertility treatment). Acute or chronic, lung, heart, liver or kidney disease. Fever of 38°C or higher, or active illness at time of vaccination. Active autoimmune disease requiring therapeutic intervention. History of dementia or any medical condition that moderately or severely impairs cognition. History of a severe adverse or allergic reaction (e.g., anaphylaxis) associated with a vaccine. Serious or unstable long-term illnesses. Severe allergic reaction to any vaccine or to components of the study vaccine. Previous RSV, hMPV, or PIV3 vaccine at any time. Planned non-study RSV, hMPV, or PIV3 vaccine during the study. Received any other vaccine within 14 days before or 28 days after study vaccination. Participation in another clinical study within 30 days before vaccination or during the study period. Received immunoglobulin or blood products within 60 days before vaccination or planned during the study. Positive test for hepatitis B, hepatitis C, or HIV at screening. Skin condition and/or tattoo that might interfere with the evaluation of the injection site on the upper arm. Any condition or risk that may interfere with the study or participant safety, based on the investigator’s judgment.