• Participants of the RSV OA=ADJ-023 study from the Per Protocol Set (Visit 3 for participants in IC\_1 and Visit 4 for participants in IC\_2 group), who received either 1 or 2 doses of the adjuvanted RSVPreF3 vaccine and for whom the immunogenicity data are available.

• Participants who, can and will comply with the requirements of the protocol (e.g., completion of the paper diary cards (as applicable), return for follow-up visits, ability to access and utilize a phone or other electronic communications, have regular contact to allow evaluation during the study).

• Written or witnessed informed consent obtained from the participant prior to performance of any study-specific procedure.

• Female participants of nonchildbearing potential may be enrolled in the study. Non childbearing potential is defined as hysterectomy, bilateral oophorectomy, bilateral salpingectomy, and post-menopause.

• Female participants of childbearing potential may be enrolled in the study if the participant:

• has practiced adequate contraception from 1 month prior to study intervention administration, and

• agreed to continue adequate contraception until 1 month after study intervention, and

• has a negative pregnancy test on the day of and prior to study intervention administration.

• Participant who has received an ABO compatible allogeneic kidney or lung transplant (allograft) more than 12 months (365 days) prior to the study intervention administration.

• Participant receiving maintenance immunosuppressive therapy for the prevention of allograft rejection.

⁃ • Participant with stable kidney function, stability defined as less than 20% variability between last two results of eGFR or in the opinion of the investigator after investigator review of more than the last two results of eGFRs and based on medical history.