A Study on the Immune Response and Safety of a Vaccine Against Respiratory Syncytial Virus (RSV) When Given Alone and Together With a COVID-19 mRNA Vaccine in Adults Aged 50 Years and Above

A Phase 3, Open-label, Randomized, Controlled Study to Evaluate the Immune Response, Safety and Reactogenicity of RSVPreF3 OA Investigational Vaccine When Co-Administered With a COVID-19 mRNA Vaccine (Omicron XBB.1.5) in Adults Aged 50 Years and Above

This study is assessing the immunogenicity, safety and reactogenicity of the RSVPreF3 OA investigational vaccine when it is co-administered with a COVID-19 messenger ribonucleic acid (mRNA) vaccine (Omicron XBB.1.5), compared to administration of the vaccines separately in adults aged 50 years and above.

Study Overview

• Status: Completed
• Conditions: Respiratory Syncytial Virus Infections
• Intervention / Treatment: Biological: RSVPreF3 OA investigational vaccine; Biological: COVID-19 mRNA vaccine

• Study Type: Interventional
• Enrollment (Actual): 841
• Phase: Phase 3

Contacts and Locations

Study Locations

• Belgium
  • Antwerp, Belgium, 2000
    • GSK Investigational Site
  • Edegem, Belgium, 2650
    • GSK Investigational Site
  • Ghent, Belgium, 9000
    • GSK Investigational Site
  • Kluisbergen, Belgium, 9690
    • GSK Investigational Site
  • Mechelen, Belgium, 2800
    • GSK Investigational Site
• Netherlands
  • Breda, Netherlands, 4818 CK
    • GSK Investigational Site
  • Enschede, Netherlands, 7512 KZ
    • GSK Investigational Site
  • Utrecht, Netherlands, 3584 BA
    • GSK Investigational Site
  • Zutphen, Netherlands, 7207 AE
    • GSK Investigational Site
• Spain
  • A Coruña, Spain, 15006
    • GSK Investigational Site
  • Barcelona, Spain, 08907
    • GSK Investigational Site
  • Barcelona, Spain, 08023
    • GSK Investigational Site
  • Boadilla Del Monte Madrid, Spain, 28660
    • GSK Investigational Site
  • Madrid, Spain, 28041
    • GSK Investigational Site
  • Madrid, Spain, 28040
    • GSK Investigational Site
  • Madrid, Spain, 28222
    • GSK Investigational Site
• United States
  • Florida
    • Coral Gables, Florida, United States, 33134
      • GSK Investigational Site
  • Georgia
    • Savannah, Georgia, United States, 31406
      • GSK Investigational Site
  • Indiana
    • Evansville, Indiana, United States, 47714
      • GSK Investigational Site
  • Nebraska
    • Omaha, Nebraska, United States, 68134
      • GSK Investigational Site
  • New York
    • Rochester, New York, United States, 14609
      • GSK Investigational Site
  • North Carolina
    • Winston-Salem, North Carolina, United States, 27103
      • GSK Investigational Site
  • South Carolina
    • North Charleston, South Carolina, United States, 29405
      • GSK Investigational Site
  • Virginia
    • Newport News, Virginia, United States, 23606
      • GSK Investigational Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the diary cards, return for follow-up visits).

Note: In case of physical incapacity that would preclude the self-completion of the diary cards, 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). However, at no time will the site staff or caregiver evaluate the participant's health status while answering diaries or make decisions on behalf of the participant.

• Written or witnessed informed consent obtained from the participant (participant must be able to understand the informed consent) prior to performance of any study-specific procedure.
• A male/female of ≥50 Years of age (YOA) at the time of the first study intervention administration.
• 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.

A stable medical condition is defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 3 months before enrollment.

• 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 have received previously a SARS-CoV-2 vaccine, being administered at least 3 months prior to study vaccination.

• Female participants of non-childbearing 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 for at least 1 month after the last vaccination.
  • has a negative pregnancy test on the day of and prior to study intervention administration.

Exclusion Criteria:

Medical Conditions

• History of any reaction or hypersensitivity likely to be exacerbated by any component of the study interventions, including a known history of severe allergic reaction (e.g., anaphylaxis).
• Any confirmed or suspected immunosuppressive or immunodeficient condition, resulting from disease (e.g., current malignancy, human immunodeficiency virus) or immunosuppressive/cytotoxic therapy (e.g., medication used during cancer chemotherapy, organ transplantation, or to treat autoimmune disorders), based on medical history and physical examination (no laboratory testing required).
• Any history of myocarditis or pericarditis.
• Recurrent history 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 (e.g. completion of diary cards, attend regular phone calls/study site visits).
• Serious or unstable chronic illness.
• Any history of dementia or any medical condition that moderately or severely impairs cognition.
• Significant underlying illness that in the opinion of the investigator would be expected to prevent completion of the study (e.g., life-threatening disease likely to limit survival up to study end).
• Any medical condition that in the judgment of the investigator would make intramuscular injection unsafe.
• Any SAE attributed to a previous dose of the SARS-CoV-2 mRNA vaccine.
• Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study.
• Recent SARS-CoV-2 infection within 3 months prior to the COVID-19 vaccine dose administration. Timelines to be determined from symptoms onset or positive COVID-19 test (if infection was asymptomatic).

Prior/Concomitant Therapy Use of any investigational or non-registered product (drug, vaccine or invasive 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 vaccine administration, or their planned use during the study period.

• Planned administration of a vaccine in the period starting 30 days before the first dose and ending 30 days after the last dose of study intervention(s) administration*, with the exception of inactivated and subunit influenza vaccines which can be administered up to 14 days before or from 14 days after the study vaccination.

  *If emergency mass vaccination for an unforeseen public health threat (e.g., a pandemic) is recommended and/or organized by 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 Sponsor is notified.

• Chronic administration of immune-modifying drugs (defined as more than 14 consecutive days in total) and/or planned use of long-acting immune-modifying treatments at any time up to the last blood sampling visit.

  • Up to 3 months prior to the study intervention administration:

    • For corticosteroids, this will mean prednisone equivalent ≥ 20 mg/day. Inhaled and topical steroids are allowed.
    • Administration of immunoglobulins and/or any blood products or plasma derivatives.
  • Up to 6 months prior to study intervention administration: long-acting immune modifying drugs including among others immunotherapy (e.g., TNF-inhibitors), monoclonal antibodies and antitumoral medication.
• Administration of any SARS-CoV-2 vaccine during the 3 months preceding the study COVID-19 mRNA vaccine administration.
• Previous vaccination with licensed or investigational RSV vaccine. 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 intervention (drug/invasive medical device).

Other Exclusion Criteria

• Pregnant or lactating female participant.
• Female participant planning to become pregnant or planning to discontinue contraceptive precautions.
• 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.
• Participation of any study personnel or their immediate dependents, family, or household members.
• Planned move during the study conduct that prohibits participation until study end.
• Bedridden participants.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Co-Ad Group; Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.	Biological: RSVPreF3 OA investigational vaccine; 1 dose of RSVPreF3 OA investigational vaccine is administered intramuscularly on Day 1 to participants in the Co-ad Group and on Day 31 to participants in the Control Group.; Biological: COVID-19 mRNA vaccine; 1 dose of COVID-19 mRNA vaccine is administered intramuscularly on Day 1 to participants in the Co-ad and Control Groups.
Active Comparator: Control Group; Participants received a single dose of COVID-19 mRNA vaccine at Day 1, followed by a single dose of RSVPreF3 OA vaccine at Day 31.	Biological: RSVPreF3 OA investigational vaccine; 1 dose of RSVPreF3 OA investigational vaccine is administered intramuscularly on Day 1 to participants in the Co-ad Group and on Day 31 to participants in the Control Group.; Biological: COVID-19 mRNA vaccine; 1 dose of COVID-19 mRNA vaccine is administered intramuscularly on Day 1 to participants in the Co-ad and Control Groups.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adjusted Geometric Mean Titers (GMT) of Respiratory Syncytial Virus-A (RSV-A) Neutralizing Titers at 1 Month After the RSVPreF3 OA Vaccination	RSV-A neutralizing titers were provided as group GMTs and expressed as estimated dilution 60 (ED60) titers. Adjusted GMTs are derived using an ANCOVA model on log10-transformed titers for the neutralization assay. The final ANCOVA model adjusted for baseline differences (in the pre-dose titers) includes treatment group and age category (age at vaccination: 50-59, 60-69 or ≥70 years) as fixed effects, and the pre-dose log10-transformed titers as a covariate.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)
Adjusted GMTs of RSV-B Neutralizing Titers at 1 Month After the RSVPreF3 OA Vaccination	RSV-B neutralizing titers were provided as group GMTs and expressed as estimated dilution 60 (ED60) titers. Adjusted GMTs are derived using an ANCOVA model on log10-transformed titers for the neutralization assay. The final ANCOVA model adjusted for baseline differences (in the pre-dose titers) includes treatment group and age category (age at vaccination: 50-59, 60-69 or ≥70 years) as fixed effects, and the pre-dose log10-transformed titers as a covariate.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)
Adjusted GMTs of SARS-CoV-2 Omicron XBB.1.5 Neutralizing Titers at 1 Month After the COVID-19 mRNA Vaccination	SARS-CoV-2 Omicron XBB.1.5 neutralizing titers against the pseudovirus bearing S protein were provided as group GMTs and expressed as titers. The neutralizing titer was calculated as the reciprocal serum dilution corresponding to the 50% signal reduction (NT50). Adjusted GMTs are derived using an ANCOVA model on log10-transformed titers for the neutralization assay. The final ANCOVA model adjusted for baseline differences (in the pre-dose titers) includes treatment group and age category (age at vaccination: 50-59, 60-69 or ≥70 years) as fixed effects, and the pre-dose log10-transformed titers as a covariate.	At 1 month post-COVID-19 mRNA vaccine dose administration (at Day 31 for both groups)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
RSV-A Neutralizing Titers Expressed as GMT at 1 Month After RSVPreF3 OA Vaccination	Neutralizing titers for RSV-A were measured with neutralizing assay and the results were expressed as GMT. GMT is a descriptive statistic calculated directly from the observed titer values at the 1-month post-vaccination timepoint for all participants in the analysis set, without any statistical modelling or adjustment for covariates.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)
Mean Geometric Increase (MGI) of RSV-A Neutralizing Titers at 1 Month After RSVPreF3 OA Vaccination	The MGI was defined as the geometric mean of the within participant ratios of the post-vaccination titer over the pre-vaccination titer.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group) compared to pre-vaccination (Day 1 for Co-Ad Group and Day 31 for Control Group)
RSV-A Neutralizing Titers Expressed as Seroresponse Rate (SRR) at 1 Month After RSVPreF3 OA Vaccination	The SRR was defined as the percentage of participants having a fold increase in neutralizing titers (1 month post-study intervention administration over pre-study intervention administration) greater than or equal to (>=) 4.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group) compared to pre-vaccination (Day 1 for Co-Ad Group and Day 31 for Control Group)
Percentage of Participants Having RSV-A Neutralizing Titers Greater or Equal to the Assay Cut-off Value at Pre-vaccination and at 1 Month After RSVPreF3 OA Vaccination	Percentage of participants with RSV-A neutralizing titers >= to the assay cut-off value (i.e. lower limit of quantification [LLOQ]) are presented.	At pre-vaccination (Day 1 for Co-Ad Group and Day 31 for Control Group) and at 1 month post-RSVPreF3 OA vaccine dose administration (Day 31 for Co-Ad Group and Day 61 for Control Group)
RSV-B Neutralizing Titers Expressed as GMT at 1 Month After RSVPreF3 OA Vaccination	Neutralizing titers for RSV-B were measured with neutralizing assay and the results were expressed as GMT. GMT is a descriptive statistic calculated directly from the observed titer values at the 1-month post-vaccination timepoint for all participants in the analysis set, without any statistical modelling or adjustment for covariates.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)
MGI of RSV-B Neutralizing Titers at 1 Month After RSVPreF3 OA Vaccination	The MGI was defined as the geometric mean of the within participant ratios of the post-vaccination titer over the pre-vaccination titer.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group) compared to pre-vaccination (Day 1 for Co-Ad Group and Day 31 for Control Group)
RSV-B Neutralizing Titers Expressed as SRR at 1 Month After RSVPreF3 OA Vaccination	The SRR was defined as the percentage of participants having a fold increase in neutralizing titers (1 month post-study intervention administration over pre-study intervention administration) >= 4.	At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group) compared to pre-vaccination (Day 1 for Co-Ad Group and Day 31 for Control Group)
Percentage of Participants Having RSV-B Neutralizing Titers Greater or Equal to Assay Cut-off Value at Pre-vaccination and at 1 Month After RSVPreF3 OA Vaccination	Percentage of participants with RSV-B neutralizing titers >= to the assay cut-off value (i.e. LLOQ) are presented.	At pre-vaccination (Day 1 for Co-Ad Group and Day 31 for Control Group) and at 1 month post-RSVPreF3 OA vaccine dose administration (Day 31 for Co-Ad Group and Day 61 for Control Group)
SARS-CoV-2 Omicron XBB.1.5 Neutralizing Titers Expressed as GMT at 1 Month After COVID-19 mRNA Vaccination	The SARS-CoV-2 Omicron XBB.1.5 neutralizing titers against the pseudovirus bearing S protein were measured with neutralizing assay and the results were expressed as GMT. GMT is a descriptive statistic calculated directly from the observed titer values at the 1-month post-vaccination timepoint for all participants in the analysis set, without any statistical modelling or adjustment for covariates.	At 1 month post-COVID-19 mRNA vaccine dose administration (Day 31 for both groups)
MGI of SARS-CoV-2 Omicron XBB.1.5 Neutralizing Titers at 1 Month After COVID-19 mRNA Vaccination	The MGI was defined as the geometric mean of the within participant ratios of the post-vaccination titer over the pre-vaccination titer.	At 1 month post-COVID-19 mRNA vaccine dose administration (Day 31 for both groups) compared to pre-vaccination (at Day 1 for both groups)
Percentage of Participants Having SARS-CoV-2 Omicron XBB.1.5 Neutralizing Titers Greater Than or Equal to Assay Cut-off Value at Pre-vaccination and at 1 Month After COVID-19 mRNA Vaccination	Percentage of participants with SARS-CoV-2 Omicron XBB.1.5 neutralizing titers >= to the assay cut-off value (i.e. LLOQ) are presented.	At pre-vaccination (Day 1 for both groups) and at 1 month post-COVID-19 mRNA vaccine dose administration (Day 31 for both groups)
Number of Participants Reporting Each Solicited Administration Site Event, for Each Type of Vaccine Administered	The solicited administration site events after vaccination included pain, erythema/redness, and swelling. Any = occurrence of the events regardless of the intensity grade.	Within 4 days (the day of administration and 3 subsequent days) after each type of vaccine (RSVPreF3 OA vaccine administered at Day 1 for Co-Ad Group and at Day 31 for Control Group, COVID-19 mRNA vaccine administered at Day 1 for both groups)
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered	The solicited systemic events after vaccination included arthralgia, fatigue, fever (pyrexia), headache and myalgia. Fever was defined as body temperature equal or greater than 38 degrees Celsius (°C). Any = occurrence of the events regardless of the intensity grade.	Within 4 days (the day of dose administered and 3 subsequent days) after each dose (administered at Day 1 for Co-Ad Group and at Days 1 and 31 for Control Group)
Number of Participants Reporting Unsolicited Adverse Events (AEs), for Each Day of Dose Administered	An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of a study vaccine, which does not necessarily have a causal relationship with study vaccine. An unsolicited AE was an AE that was either not included in the list of solicited events or could be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events. Unsolicited AEs must had been communicated by participant/participant's caregiver(s) who had signed the informed consent. Unsolicited AEs included both serious and non-serious AEs. Any = occurrence of the events regardless of the intensity grade or relation to study dose administration.	Within 30 days (the day of vaccination and 29 subsequent days) after each dose (dose administered at Day 1 for Co-Ad Group and at Days 1 and 31 for Control Group)
Number of Participants Reporting Any Serious Adverse Events (SAEs)	An SAE was defined as any untoward medical occurrence that, at any dose, resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. Any = occurrence of the events regardless of the intensity grade or relation to study dose administration.	Throughout the study period (from Day 1 up to 6 months after the last dose administration [last dose given at Day 1 for Co-Ad Group and Day 31 for Control Group])
Number of Participants Reporting Any Potential Immune-mediated Diseases (pIMDs)	The pIMD was defined as a subset of adverse events of special interest that included autoimmune diseases and other inflammatory and/or neurologic disorders of interest which may or may not have an autoimmune etiology. Any = occurrence of the events regardless of the intensity grade or relation to study dose administration.	Throughout the study period (from Day 1 up to 6 months after the last dose administration [last dose given at Day 1 for Co-Ad Group and Day 31 for Control Group])

Collaborators and Investigators

• Sponsor: GlaxoSmithKline

Study record dates

Study Major Dates

• Study Start (Actual): April 29, 2024
• Primary Completion (Actual): November 1, 2024
• Study Completion (Actual): March 31, 2025

Study Registration Dates

• First Submitted: April 16, 2024
• First Submitted That Met QC Criteria: April 16, 2024
• First Posted (Actual): April 18, 2024

Study Record Updates

• Last Update Posted (Actual): December 26, 2025
• Last Update Submitted That Met QC Criteria: December 8, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Safety; Older Adults; Immunogenicity; Reactogenicity; RSV; Respiratory Syncytial Virus; COVID-19 mRNA vaccine
• Additional Relevant MeSH Terms: Infections; RNA Virus Infections; Virus Diseases; Pneumovirus Infections; Paramyxoviridae Infections; Mononegavirales Infections; Respiratory Syncytial Virus Infections; Immunologic Factors; Physiological Effects of Drugs; CVnCoV COVID-19 vaccine
• Other Study ID Numbers: 217848; 2023-510196-59-00 (Other Identifier: EU CTR Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 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.
• IPD Sharing Time Frame: 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.
• IPD Sharing Access Criteria: 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.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No