Efficacy Study of GSK's Investigational Respiratory Syncytial Virus (RSV) Vaccine in Adults Aged 60 Years and Above

GlaxoSmithKline26,675 enrolled

Overview

This study will evaluate the efficacy of the RSVPreF3 OA investigational vaccine in preventing Lower Respiratory Tract Disease (LRTD) caused by RSV in adults ≥60 years of age following a single dose of the RSVPreF3 OA vaccine and following annual revaccination doses in Northern Hemisphere (NH) and in Southern Hemisphere (SH). This study will also assess if the vaccine is safe and induces an immune response.

Dose 1 Period will be conducted in 2 parts: Part 1: Participants in RSVPreF3 groups will receive lots 1, 2 and 3 of the investigational vaccine before Season 1. Part 2: Will be initiated when the vaccine lots in part 1 are exhausted at the study sites and participants in RSVPreF3 group will receive lot 4 of the investigational vaccine before Season 1.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

QUADRUPLE

Enrollment

26,675

Conditions

Respiratory Syncytial Virus Infections

Interventions

PlaceboBIOLOGICAL

Placebo administered intramuscularly into the deltoid of the non-dominant arm at day 1 and before Season 2 to the Placebo Group, and before Season 2 to the participants of the RSVPreF3 Group, that are re-randomized to the RSV\_1 dose group.

RSVPreF3 OA vaccineBIOLOGICAL

RSVPreF3 OA vaccine administered intramuscularly into the deltoid of the non-dominant arm at Day 1 in the RSVPreF3 group, and before Season 2 to the participants of the RSVPreF3 group that are re-randomized to the RSV\_annual group.

Eligibility

Sex: ALLMin age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * A male or female ≥ 60 YOA at the time of first vaccination, who live in the community (community dwelling participants) or in a long-term care facility (LTCF participants). * Participants who, in the opinion of the investigator, can and will comply with the requirements of the protocol. Note: In case of physical incapacity that would preclude the self-completion of the diary cards and/or questionnaires, either site staff can assist the participant (for activities performed during site visits) or the participant may assign a caregiver to assist him/her with this activity (for activities performed at home or in the LTCF). However, at no time, the site staff or caregiver will evaluate the participant's health status while answering diaries and/or questionnaires or make decisions on behalf of the participant * Written or witnessed informed consent obtained from the participant prior to performance of any study specific procedure. * Participants who are medically stable in the opinion of the investigator at the time of first vaccination. Participants with chronic stable medical conditions with or without specific treatment, such as diabetes, hypertension or cardiac disease, are allowed to participate in this study if considered by the investigator as medically stable. Exclusion Criteria: Medical conditions * Any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease or immunosuppressive/cytotoxic therapy, based on medical history and physical examination (no laboratory testing required). * History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine. * Hypersensitivity to latex. * Serious or unstable chronic illness. * Any history of dementia or any medical condition that moderately or severely impairs cognition. Note: If deemed necessary for clinical evaluation, the investigator can use tools such as Mini-Mental State Exam (MMSE), Mini-Cog or Montreal Cognitive Assessment (MoCA) to determine cognition levels of the participant. * Recurrent or un-controlled neurological disorders or seizures. Participants with medically-controlled active 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. Prior/Concomitant therapy * Use of any investigational or non-registered product (drug, vaccine or medical device) other than the study vaccine during the period beginning 30 days before the first study vaccine administration, or 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 each dose and ending 30 days after each dose of study vaccine administration, with the exception of inactivated and subunit influenza vaccines which can be administered up to 14 days before or from 14 days after each study vaccination. * Previous vaccination with an RSV vaccine. * 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 first study vaccine 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 vaccine administration or planned administration during the study period. For corticosteroids, this will mean prednisone ≥20 mg/day, or equivalent. Inhaled and topical steroids are allowed. Prior/Concurrent clinical study experience • 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 medical device). Other exclusions * 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 period that will prohibit participating in the trial until study end. This includes: * Planned move during the study period to another LTCF that will prohibit participation in the trial until study end. * Planned move from the community to a LTCF that will prohibit participation in the trial until study end. * Participation of any study personnel or their immediate dependants, family, or household members. * Planned leave or holiday of 4 consecutive weeks or more during the RSV seasons\* covered by the study, that would prohibit the reporting of ARI cases and attendance to ARI visit. * RSV seasons are from October to April in NH and from March to September in SH.

Locations (277)

Outcomes

Primary Outcomes

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated Lower Respiratory Tract Disease (LRTD) During the First Season Following a Single Dose of the RSVPreF3 OA Vaccine

First episode of Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR)-confirmed RSV A and/or RSV B- associated LRTD during the first season was assessed. The case definition for RSV-confirmed LRTD is as follows: Presence of at least one RSV-positive swab detected by RT-PCR.

Time frame: From Day 15 post-vaccination up to end of season 1 in the Northern Hemisphere (NH) [a median of approximately 6.7 months (6.9 months in NH and 3.5 months in Southern Hemisphere [SH])]

Secondary Outcomes

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD Over Several Seasons Following a Single Dose of the RSVPreF3 OA Vaccine

Efficacy of a single dose of the RSVPreF3 OA vaccine was assessed against RSV A and/or B confirmed LRTD over several seasons according to the case definition.

Time frame: From Day 15 post first vaccination up to end of season 2 and up to end of season 3 in the Northern Hemisphere [NH] (assessed approximately over 2 and 3 years in NH)

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD Over Several Seasons Following Annual Revaccination Doses of the RSVPreF3 OA Vaccine

Efficacy of annual revaccination doses of the RSVPreF3 OA vaccine was assessed against RSV A and/or B confirmed LRTD over several seasons according to the case definition.

Time frame: From Day 15 post first vaccination up to end of season 2 and up to end of season 3 in the NH (assessed approximately over 2 and 3 years in NH)

Number of Participants With First Episode of RT-PCR Confirmed RSV Subtype A and Subtype B LRTD Over 3 Seasons Following a Single Dose of the RSVPreF3 OA Vaccine

Efficacy of a single dose of the RSVPreF3 OA vaccine was assessed against LRTD episode caused by RSV A and B subtype over 3 seasons according to the case definition.

Data from ClinicalTrials.gov

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GSK Investigational Site

Birmingham, Alabama, United States

GSK Investigational Site

Birmingham, Alabama, United States

GSK Investigational Site

Huntsville, Alabama, United States

GSK Investigational Site

Phoenix, Arizona, United States

GSK Investigational Site

Tucson, Arizona, United States

GSK Investigational Site

Cerritos, California, United States

GSK Investigational Site

Laguna Hills, California, United States

GSK Investigational Site

Coral Gables, Florida, United States

GSK Investigational Site

Fort Myers, Florida, United States

GSK Investigational Site

Jacksonville, Florida, United States

...and 267 more locations

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH, and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed RSV Subtype A and Subtype B LRTD Over 3 Seasons Following a Single Dose of the RSVPreF3 OA Vaccine and Following 1 Annual Revaccination Dose

Efficacy of a single dose and 1 annual revaccination dose of the RSVPreF3 OA vaccine was assessed against LRTD episode caused by RSV A and B subtype over 3 seasons according to the case definition.

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH, and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed LRTD Caused by Human Metapneumovirus (hMPV) up to the End of Season 1 Following a Single Dose of the RSVPreF3 OA Vaccine

Time frame: From Day 15 post-vaccination up to end of season 1 in the SH [a median of approximately 11.5 months (11.6 months in NH and 9.1 months in SH)]

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD, by Age Categories Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses was assessed against RSV A and/or B confirmed LRTD episode according to the case definition, in the following age categories: greater than or equal to (≥) 65 years of age (YOA), ≥70 YOA and ≥80 YOA.

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD by RSV Season Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses was assessed against RSV A and/or B confirmed LRTD episode according to the case definition, by RSV season as follows: VE after each season includes the first occurrence of episodes reported from Day 15 post vaccination at first season, and for the next seasons, excluding analysis of participants who already reported a case in the previous season. The RSV season may be extended based on epidemiology data.

Time frame: From Day 15 post first dose or start of the RSV season to the first occurrence of RSV-confirmed LRTD at each RSV season (assessed approximately over 7 months at each season [Seasons 1 and 2 in SH, Seasons 1, 2 and 3 in NH])

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD by Year Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses was assessed against RSV A and/or B confirmed LRTD episode according to the case definition, by years after vaccination as follows: VE at each year includes the first occurrence of episodes reported from Day 14 post vaccination at first year, and for the next years, excluding analysis of participants who already reported a case in the previous year.

Time frame: From Day 15 post first dose and each revaccination dose up to next dose or end of study (assessed approximately over a year after each vaccination [at Year 1, Year 2 and Year 3])

Number of Participants With First Episode of RT-PCR Confirmed RSV A and /or B Associated LRTD, Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Time frame: From Day 15 post first dose to the first occurrence of RSV LRTD (assessed approximately over 3 years in the NH and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD by Baseline Comorbidities Using Charlson Comorbidity Index Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses is assessed against RSV A and/or B associated LRTD episode by baseline comorbidities using Charlson Comorbidity Index. Low/medium Risk = Participants with co-morbidity score at baseline less than or equal to 3 (Charlson Index); High Risk = Participants with co-morbidity score at baseline greater than 3 (Charlson Index).

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD by Baseline Comorbidities According to Comorbidities of Interest Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses is assessed against RSV A and/or B associated LRTD episode by baseline comorbidities of interest divided into 2: cardiorespiratory conditions such as chronic obstructive pulmonary disease (COPD), asthma, any chronic respiratory or pulmonary disease, and endocrinometabolic conditions such as diabetes mellitus type 1 or 2, chronic heart failure and advanced liver or renal disease.

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated LRTD by Baseline Frailty Status Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses is assessed against RSV A and /or B associated LRTD episode according to the case definition, by baseline frailty status of frail, pre-frail and fit. Frail = Participants with a walking speed of less than (\<) 0.4 meters per second (m/s) or who were not able to perform the test; Pre-Frail = Participants with a walking speed between 0.4-0.99 m/s; Fit = Participants with a walking speed of ≥1 m/s.

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated Severe LRTD Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses is assessed against RSV A and/or B associated severe LRTD episode. Case definition for RSV-confirmed severe LRTD: An RT-PCR confirmed case of RSV-associated severe LRTD is characterized by presence of lower respiratory signs or an LRTD episode assessed as severe by the investigator (Severe LRTD case definition 1) or presence of an LRTD with need for oxygen supplementation or need for positive airway pressure therapy or need for other types of mechanical ventilation (Severe LRTD case definition 2) and with at least one RSV positive swab detected by RT-PCR.

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH and 2.5-3 years in SH)

Number of Participants With First Episode of RT-PCR Confirmed RSV A and/or B Associated ARI Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses is assessed against RSV confirmed A and/or B associated ARI episode. A case of RT-PCR confirmed RSV-associated ARI is characterized by the presence of respiratory symptoms/signs for at least 24 hours OR respiratory symptom/sign + systemic symptom/sign for at least 24 hours with at least one RSV-positive swab detected by RT-PCR.

Time frame: From Day 15 post first vaccination up to end of season 3 in the NH (assessed approximately over 3 years in NH and 2.5-3 years in SH)

Number of Participants With First Episode of Any ARI or Any LRTD Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

Efficacy of a single dose of the RSVPreF3 OA vaccine and annual revaccination doses is assessed against any ARI and any LRTD.

Time frame: From Day 15 post first vaccination up to study end (approximately 3 years for NH and 2.5-3 years for SH)

Number of Hospitalizations Due to RSV-confirmed Respiratory Diseases or Due to Complication Related to RSV-confirmed Respiratory Diseases, Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses up to End of Study

RSV infection was confirmed by RT-PCR.

Time frame: From Day 15 post-first vaccination up to study end (approximately 3 years for NH and 2.5-3 years for SH)

Number of Hospitalizations Due to Any Respiratory Diseases or Due to a Complication Related to Any Respiratory Diseases, During the RSV Seasons Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses up to End of Study

A diagnosis of respiratory disease included: acute respiratory infections, other diseases of upper respiratory tract, pneumonia and influenza, chronic obstructive pulmonary disease and allied conditions, pneumoconioses and other lung diseases due to external agents, other diseases of respiratory system.

Time frame: From Day 15 post-first vaccination up to study end (approximately 3 years for NH and 2.5-3 years for SH)

Number of Complications Related to RSV-confirmed ARI During the RSV Seasons Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses up to End of Study

RSV infection was confirmed by RT-PCR.

Time frame: From Day 15 post-first vaccination up to study end (approximately 3 years for NH and 2.5-3 years for SH)

Number of Complications Related to Any ARI During the RSV Seasons Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses up to End of Study

RSV infection was confirmed by RT-PCR.

Time frame: From Day 15 post-first vaccination up to study end (approximately 3 years for NH and 2.5-3 years for SH)

Maximum Influenza Patient-Reported Outcome (Flu-PRO) Chest Score for the Participants With RT-PCR-confirmed RSV A and/or B-associated ARI Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

For this outcome measure, the Health Related -Quality of life (HR-QOL) score is measured by Flu-PRO questionnaire version 2.0. The Flu-PRO is a 32 items daily diary, which assesses influenza signs across 6 body systems- nose, throat, eyes, chest/respiratory, gastrointestinal and body/systemic. The objective of this outcome measure was to present data only for chest/respiratory system after a single dose and after annual revaccination. The FLU-PRO score was computed as the mean score across questionaire items for chest/respiratory body system, with the scores ranging from 0 (symptom free) to 4 (very severe symptoms).

Time frame: During the first 7 days from the onset of ARI symptoms (assessed from Day 15 post first vaccination dose until end of study [approximately 3 years in NH and 2.5-3 years in SH])

Least Square Mean Flu-PRO Total Score for the Participants With RT-PCR-confirmed RSV A and/or B-associated ARI Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

The Flu-PRO questionnaire version 2.0 is a 32 items daily diary, which assesses influenza signs across 6 body systems- nose, throat, eyes, chest/respiratory, gastrointestinal and body/systemic. The FLU-PRO total score was computed as the mean score across all 32 items of the questionaire for all 6 body systems, with the total scores ranging from 0 (symptom free) to 4 (very severe symptoms).

Time frame: During the first 7 days from the onset of ARI symptoms (assessed from Day 15 post first vaccination dose until end of study [approximately 3 years in NH and 2.5-3 years in SH])

EuroQol 5-dimension Health Questionnaire (EQ-5D) Utility Score for Participants With RT-PCR-confirmed RSV A and/or B-associated ARI Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

The EQ-5D is a general health utility questionnaire with health states, defined through 5 dimensions- mobility, self-care, usual activities, pain/ discomfort and anxiety/ depression. A participant who responds 1 (no problem/no symptom) to all 5 items has a profile "11111" and similarly a participant who responds 3 (the highest level of difficulty or symptom) to all items has a profile "33333". The health states indicated in these 5 dimensions are converted and presented as a single mean index value as recommended by EuroQol group, where values range from 0 (worst) to 1 (full health).

Time frame: At the ARI visit (assessed from Day 15 post first vaccination dose until end of study- approximately 3 years in NH and 2.5-3 years in SH)

Least Square Mean of Short Form-12 (SF-12) Health Survey for Participants With RT-PCR Confirmed RSV A and/or B-associated ARI Following a Single Dose of the RSVPreF3 OA Vaccine and Following Annual Revaccination Doses

SF-12 is a health survey with 12 questions, covering 8 domains- physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional and mental health. Summary scores are computed from these domains for the physical and mental component. The total score of the SF-12 questionnaire is evaluated on a scale from 0 to 100, with a higher score indicating a better perceived health-related quality of life.

Time frame: At the ARI visit (assessed from one-month post first vaccination dose until end of study- approximately 3 years in NH and 2.5-3 years in SH)

Duration in Days of RT-PCR Confirmed RSV A and/or B ARI and LRTD Episodes

The duration in days of RT-PCR confirmed RSV A and/or B ARI and LRTD episodes are described.

Time frame: From Day 15 post first dose to end of Season 1, from 15 days post-second dose administration to end of Season 2, and from start to end of Season 3 [all seasons summing approximately 3 years in NH and 2.5-3 years in SH]

Number of Participants With Each Reported Symptom/Sign and Supportive Therapy Use Associated With of RT-PCR Confirmed RSV A and/or B ARI Episodes During Season 1

RSV infection was confirmed by RT-PCR, and the symptoms/signs and supportive therapy use associated with RT-PCR confirmed RSV A and/or RSV B ARI episodes were reported. Fever was defined as a temperature ≥38.0 degrees Celsius (°C) by any route.

Time frame: From Day 15 post-dose 1 administration up to end of season 1 in the SH [a median of approximately 11.5 months (11.6 months in NH and 9.1 months in SH)]

Number of Participants With Each Reported Symptom/Sign and Supportive Therapy Use Associated With of RT-PCR Confirmed RSV A and/or B ARI Episodes During Season 2

Time frame: From Day 15 post-dose 2 administration up to end of Season 2 in SH (a median of approximately 11.9 months [11.9 months in NH and 7.5 months in SH])

Number of Participants With Each Reported Symptom/Sign and Supportive Therapy Use Associated With of RT-PCR Confirmed RSV A and/or B ARI Episodes During Season 3

Time frame: From start of Season 3 up to end of Season 3 in NH (a median of approximately 7 months)

Number of Participants With Each Reported Symptom/Sign and Supportive Therapy Use Associated With of RT-PCR Confirmed RSV A and/or B LRTD Episodes During Season 1

RSV infection was confirmed by RT-PCR, and the symptoms/signs and supportive therapy use associated with RT-PCR confirmed RSV A and/or RSV B LRTD episodes were reported. Fever was defined as a temperature ≥38.0°C by any route.

Time frame: From Day 15 post-dose 1 administration up to end of season 1 in the SH [a median of approximately 11.5 months (11.6 months in NH and 9.1 months in SH)]

Number of Participants With Each Reported Symptom/Sign and Supportive Therapy Use Associated With of RT-PCR Confirmed RSV A and/or B LRTD Episodes During Season 2

Time frame: From Day 15 post-dose 2 administration up to end of Season 2 in SH (a median of approximately 11.9 months [11.9 months in NH and 7.5 months in SH])

Number of Participants With Each Reported Symptom/Sign and Supportive Therapy Use Associated With of RT-PCR Confirmed RSV A and/or B LRTD Episodes During Season 3

Time frame: From start of Season 3 up to end of Season 3 in NH (a median of approximately 7 months)

Number of Participants With RT-PCR Confirmed RSV A and/or B ARI and LRTD Episodes According to Severity

RSV A and/or B ARI and LRTD episodes were assessed as "mild", "moderate" or "severe" by the investigator after the single dose and after annual revaccination. Mild = an ARI/LRTD episode which is easily tolerated by the participant, causing minimal discomfort and not interfering with everyday activities. Moderate = an ARI/LRTD episode which is sufficiently discomforting to interfere with normal everyday activities. Severe = an ARI/LRTD episode which prevents normal, everyday activities.

Time frame: Assessed during the study period (approximately 3 years for NH and 2.5-3 years for SH)

RSVPreF3 Specific Immunoglobulin G(IgG) Antibody Concentrations

The RSVPreF3 IgG antibody concentrations are expressed as geometric mean concentrations (GMCs) in ELISA units per milliliter (EU/mL).

Time frame: At pre-dose 1 (Day 1), Day 31 post-dose 1, pre-season 2 (approximately 10-17 months post Day 1 in NH; 12-21 months post Day 1 in SH) and pre-season 3 (approximately 24-27 months post Day 1, only in NH)

RSV A Neutralizing Antibody Titers

The RSV A neutralizing antibody titers are expressed as geometric mean titers (GMTs).

RSV B Neutralizing Antibody Titers

RSV B neutralizing antibodies are expressed as GMTs.

Number of Participants With Any and Grade 3 Solicited Administration Site Adverse Events

Time frame: During the 4-day follow up period after first vaccination (Day 1), second vaccination (administered pre-season 2) and after the third vaccination (administered pre-season 3 -only applicable for participants in NH])

Number of Participants With Any and Grade 3 Solicited Systemic Adverse Events

Any solicited event is defined as the occurrence of any solicited adverse event (AE) regardless of intensity grade or relation to study vaccination. Grade 3 = an event which prevented normal, everyday activities. The assessed solicited systemic events include arthralgia, fatigue, fever, headache and myalgia. Fever is defined as a temperature ≥ 38.0°C by any route. Grade 3 fever is defined as temperature \>39°C by any route.

Number of Days With Solicited Administration Site Adverse Events

Number of Days With Solicited Systemic Adverse Events

Number of Participants With Any Unsolicited AEs

An unsolicited AE is defined as any AE reported in addition to those solicited during the clinical study. Also, any 'solicited' symptom with onset outside of the specified period of follow-up for solicited symptoms was reported as an unsolicited AE. Any= occurrence of the event regardless of intensity grade or relation to the study vaccination.

Time frame: During the 30-day follow up period after first vaccination (Day 1), second vaccination (administered pre-season 2) and after the third vaccination (administered pre-season 3 -only applicable for participants in NH)

Number of Participants With Serious Adverse Events (SAEs)

An SAE is defined as any untoward medical occurrence that resulted in death, was life-threatening, required hospitalization or prolongation of existing hospitalization, resulted in disability/incapacity, was a congenital anomaly/birth defect in the offspring of a study participant, or in other situations that were considered serious per medical or scientific judgment. Any = occurrence of any SAE regardless of intensity grade or relation to study vaccination.

Time frame: From the day of the vaccination up to 6 months after each vaccination (first vaccination: at Day 1, second vaccination: at pre-season 2 and the third vaccination: at pre-season 3 -only applicable for participants in NH])

Number of Participants With Potential Immune Mediated Diseases (pIMDs)

pIMDs aredefined as a subset of Adverse Events of Specific Interest (AESIs) that include autoimmune diseases and other inflammatory and/or neurologic disorders of interest which may or may not have an autoimmune aetiology. Any= occurrence of any pIMD regardless of intensity grade or relation to the study vaccination.

Number of Participants With Related SAEs

Related SAEs that occur throughout the study are assessed. Related SAEs= Any SAE related to investigational vaccine or related to study participation or to a GSK concomitant medication/vaccine as assessed by the investigator.

Time frame: From Day 1 up to study end (approximately 3 years for NH and 2.5-3 years for SH)

Number of Participants With Fatal SAEs

Fatal SAEs that occur throughout the study are assessed. Fatal SAEs= Any SAEs leading to deaths.

Time frame: From Day 1 up to study end (approximately 3 years for NH and 2.5-3 years for SH)

Number of Participants With Related pIMDs

Related pIMD = pIMD assessed by the investigator as related to the study vaccination.

Time frame: From Day 1 up to study end (approximately 3 years for NH and 2.5-3 years for SH)