Efficacy Study: This randomized, double-blinded, placebo-controlled Phase 3 study is designed to assess the safety, immunogenicity, and efficacy of a single dose of RSVpreF in the prevention of LRTI-RSV in adults: * At a dose of 120µg. * In adults 60 years of age and older. * The duration of the study for each participant will be up to approximately 24 months. * The study will be conducted in the United States, Canada, Netherlands, Finland, Argentina, Japan and South Africa. Substudy A: This study is an extension of the efficacy study and was designed to evaluate the safety and immunogenicity of a second dose of RSVpreF when administered after a dosing interval of approximately 2 years: * At a dose of 120µg (as studied in the Phase 3 Efficacy Study) * Blood samples will be collected for antibody testing. * The duration of the study for each participant will be up to approximately 18 months. * The study will be conducted in the United States and Argentina. Substudy B: This study was designed to evaluate the safety and immunogenicity of a second dose of RSVpreF when administered after a dosing interval of approximately 1 year: * At a dose of 120µg (as studied in the Phase 3 Efficacy Study) * Blood samples will be collected for antibody testing. * The duration of the study for each participant will be up to approximately 18 months. * The study will be conducted in Argentina. Substudy C: This study was designed to evaluate the safety and immunogenicity of a second dose of RSVpreF when administered after a dosing interval of either 3 or 4 years: * At a dose of 120µg (as studied in the Phase 3 Efficacy Study) * Participants will receive either placebo or a second dose of RSVpreF approximately 3 or 4 years after receiving the initial dose of RSVpreF in the main efficacy study. * Blood samples will be collected for antibody testing. * The duration of the study for each participant will be up to approximately 24 months. * The study will be conducted in the United States and Canada.
RSV vaccine (RSVpreF)
Placebo
CABA, Buenos Aires, Argentina
CABA, Buenos Aires, Argentina
La Plata, Buenos Aires, Argentina
Mar del Plata, Buenos Aires, Argentina
San Miguel de Tucumán, Tucumán Province, Argentina
San Miguel de Tucumán, Tucumán Province, Argentina
Córdoba, Argentina
Salta, Argentina