To assess the ability of RSVPreF3 OA investigational vaccine to generate an immune response when given in combination with HZ/su vaccine and its safety in older adults, aged >=50 years of age.

Inclusion Criteria:

• A male or female participant ≥50 YOA at the time of the first study intervention administration.

• Female participants of non-childbearing potential may be enrolled in the study.

• 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.
  • has a negative pregnancy test on the day of and prior to study intervention administration.
  • has agreed to continue effective contraception until the end of the study.

• Participants who, in the opinion of the investigator, can and will comply with the requirements of the protocol. Written or witnessed informed consent obtained from the participant prior to any study specific procedure being performed.

• Participants living in the general community or in an assisted-living facility that provides minimal assistance, such that the participant is primarily responsible for self-care and activities of daily living.

• Participants who are medically stable in the opinion of the investigator at the time of first study intervention administration. Participants with chronic stable medical conditions with or without specific treatment, such as diabetes mellitus, hypertension, or cardiac disease, are allowed to participate in this study if considered by the investigator as medically stable.

Exclusion Criteria:

• Pregnant or lactating female.

• Female planning to become pregnant or planning to discontinue contraceptive precautions.

• Any confirmed or suspected autoimmune disorders, immunosuppressive or immunodeficient condition resulting from disease or immunosuppressive/cytotoxic therapy, based on medical history and physical examination.

• History of any reaction or hypersensitivity likely to be exacerbated by any component of the study interventions, in particular any history of severe allergic reaction to any vaccine component.

• History of Guillain-Barré syndrome.

• Any history of dementia or any medical condition that moderately or severely impairs cognition.

• Recurrent or uncontrolled neurological disorders or seizures. Participants with medically controlled chronic neurological diseases can be enrolled in the study as per investigator assessment, provided that their condition will allow them to comply with the requirements of the protocol.

• Significant underlying illness that in the opinion of the investigator would be expected to prevent completion of the study.

• Any medical condition that in the judgment of the investigator would make intramuscular injection unsafe.

• Clinically suspected or polymerase chain reaction (PCR)-confirmed ongoing episode of herpes zoster.

• History of previous vaccination with any licensed or investigational recombinant adjuvanted zoster vaccine (HZ/su vaccine; Shingrix) before the study start or planned receipt through study participation.

• History of previous vaccination with any licensed or investigational live herpes zoster vaccine (Zostavax) in the last 2 years from enrollment, or planned receipt through study participation.

• Previous vaccination with licensed or investigational RSV vaccine.

• Use of any investigational or non-registered product (drug, vaccine or medical device) other than the study interventions during the period beginning 30 days before the first dose of study interventions, or their planned use during the study period.

• Planned or actual administration of a vaccine not foreseen by the study protocol in the period starting 30 days before the first study intervention administration and ending 30 days after the last study intervention administration.

  o In the case of COVID-19 and inactivated/subunit/split influenza vaccines, this time window can be decreased to 14 days before and after each study intervention administration provided COVID-19 vaccine use is in line with local governmental recommendations.

• Planned or actual administration of adjuvanted quadrivalent influenza vaccine influenza vaccine not foreseen by the study protocol in the period starting 30 days before the first study intervention administration and ending 30 days after the last study intervention administration.

• Administration of long-acting immune-modifying drugs during the period starting 180 days before the administration of first dose of study interventions or planned administration at any time during the study period (e.g., infliximab).

• Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting 90 days before the administration of first dose of study interventions or planned administration during the study period.

• Chronic administration (defined as more than 14 consecutive days in total) of immunosuppressants or other immune modifying drugs during the period starting 90 days prior to the first study intervention dose or planned administration during the study period. For corticosteroids, this will mean prednisone ≥20 mg/day, or equivalent. Inhaled, topical or intra-articular steroids are allowed.

• Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non investigational vaccine/product (IMP) (drug or invasive medical device).

• History of chronic alcohol consumption and/or drug abuse as deemed by the investigator to render the potential participant unable/unlikely to provide accurate safety reports or comply with study procedures.Bedridden participants.

• Planned move during the study conduct that prohibits participation until study end.

• Participation of any study personnel or their immediate dependents, family, or household members.

GSK will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/About\_GSK\_Patient\_Level\_Data\_Sharing\_Final\_13July2023.pdf.

Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or terminated asset(s) across all indications.

Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension may be granted, when justified, for up to 6 months.