Study to Assess the Immune Response, the Safety and the Reactogenicity of Respiratory Syncytial Virus (RSV) Prefusion Protein 3 Older Adult (OA) (RSVPreF3 OA) Investigational Vaccine When co Administered With PCV20 in Older Adults

Inclusion Criteria: A male or female ≥60 years of age at the time of the first study intervention administration. 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, are allowed to participate in this study if considered by the investigator as medically stable. Exclusion Criteria: Any confirmed or suspected 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 the study interventions, in particular any history of severe allergic reaction to any vaccine containing diphtheria toxoid, or pneumococcal polysaccharide 23-valent vaccine (PPSV23). Participants considered by investigator as suffering from serious or unstable chronic illness. 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 active or 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. History of previous vaccination with any licensed or investigational pneumococcal conjugate vaccine, or planned receipt through study participation. History of previous vaccination with any licensed or investigational pneumococcal polysaccharide vaccine in the last 5 years from enrollment, or planned receipt through study participation. Previous vaccination with any 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 and ending 30 days after the last study intervention administration, 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. In the case of COVID 19 and inactivated/subunit influenza vaccines, this time window can be decreased to 14 days before and after each study intervention administration. In case of COVID-19 vaccine administration within 14 to 30 days window, the administration of COVID-19 vaccine should be in accordance with local government recommendations. Planned or actual administration of adjuvanted quadrivalent influenza vaccine or live 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. Note: In case an emergency mass vaccination for an unforeseen public health threat (e.g., a pandemic) is recommended and/or organized by the public health authorities outside the routine immunization program, the time period described above can be reduced if necessary for that vaccine, provided it is used according to the local governmental recommendations and that the Sponsor or designee is notified accordingly. Administration of long-acting immune-modifying drugs or planned administration at any time during the study period. 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 and topical 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 (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 EoS. Participation of any study personnel or their immediate dependents, family, or household members.