Trial Outcomes & Findings for 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 (NCT NCT06374394)

Last Updated: 2025-12-26

Results Overview

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.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

841 participants

Primary outcome timeframe

At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)

Results posted on

2025-12-26

Participant Flow

Out of 841 enrolled participants, 833 participants were randomized in a 1:1 ratio to either Co-Ad Group or Control Group at Day 1 and started the study. These participants were included in the Exposed Set.

Participant milestones

Participant milestones
Measure	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.	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.
Overall Study STARTED	417	416
Overall Study COMPLETED	409	398
Overall Study NOT COMPLETED	8	18

Reasons for withdrawal

Reasons for withdrawal
Measure	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.	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.
Overall Study Adverse Event	0	2
Overall Study Lost to Follow-up	6	9
Overall Study Withdrawal by Subject	1	7
Overall Study Other	1	0

Baseline Characteristics

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

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Co-Ad Group n=417 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.	Control Group n=416 Participants 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.	Total n=833 Participants Total of all reporting groups
Age, Continuous	63.7 YEARS STANDARD_DEVIATION 8.4 • n=30 Participants	63.5 YEARS STANDARD_DEVIATION 8.4 • n=30 Participants	63.6 YEARS STANDARD_DEVIATION 8.4 • n=60 Participants
Sex: Female, Male Female	216 Participants n=30 Participants	223 Participants n=30 Participants	439 Participants n=60 Participants
Sex: Female, Male Male	201 Participants n=30 Participants	193 Participants n=30 Participants	394 Participants n=60 Participants
Race/Ethnicity, Customized Other Races	5 Participants n=30 Participants	7 Participants n=30 Participants	12 Participants n=60 Participants
Race/Ethnicity, Customized White	378 Participants n=30 Participants	375 Participants n=30 Participants	753 Participants n=60 Participants
Race/Ethnicity, Customized Black or African American	31 Participants n=30 Participants	32 Participants n=30 Participants	63 Participants n=60 Participants
Race/Ethnicity, Customized Multiple	1 Participants n=30 Participants	1 Participants n=30 Participants	2 Participants n=60 Participants
Race/Ethnicity, Customized Not reported	2 Participants n=30 Participants	1 Participants n=30 Participants	3 Participants n=60 Participants

PRIMARY outcome

Timeframe: At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)

Population: Per protocol set (PPS) for RSVPreF3 OA included participants who: received RSVPreF3 OA, had immunogenicity results for RSV titers, complied with the blood draw interval, without intercurrent medical conditions, without prohibited concomitant medication/vaccination, did not meet criteria for elimination. Only participants included in both pre-vaccination and 1-month post vaccination timepoints and with results for adjusted GMTs for RSV-A at 1-month post dose were included in the analysis.

Outcome measures

Outcome measures
Measure	Control Group n=364 Participants 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.	Co-Ad Group n=382 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Adjusted Geometric Mean Titers (GMT) of Respiratory Syncytial Virus-A (RSV-A) Neutralizing Titers at 1 Month After the RSVPreF3 OA Vaccination	8803.4 Titers Interval 7985.0 to 9705.7	7885.8 Titers Interval 7168.1 to 8675.3

PRIMARY outcome

Timeframe: At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants included in both pre-vaccination and 1-month post vaccination timepoints and with results for adjusted GMTs for RSV-B at 1-month post dose were included in the analysis.

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.

Outcome measures

Outcome measures
Measure	Control Group n=364 Participants 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.	Co-Ad Group n=382 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Adjusted GMTs of RSV-B Neutralizing Titers at 1 Month After the RSVPreF3 OA Vaccination	7903.1 Titers Interval 7182.6 to 8695.9	7333.3 Titers Interval 6678.6 to 8052.0

PRIMARY outcome

Timeframe: At 1 month post-COVID-19 mRNA vaccine dose administration (at Day 31 for both groups)

Population: The PPS for COVID-19 mRNA included participants who:received COVID-19 mRNA, had immunogenicity results for SARS-CoV-2 titers, complied with the blood draw interval, without intercurrent medical conditions, without prohibited concomitant medication/vaccination, did not meet criteria for elimination. Only participants included in both pre-vaccination and 1-month post vaccination timepoints and with results for adjusted GMTs for SARS-CoV-2 titers at 1-month post dose were included in the analysis.

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.

Outcome measures

Outcome measures
Measure	Control Group n=381 Participants 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.	Co-Ad Group n=380 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Adjusted GMTs of SARS-CoV-2 Omicron XBB.1.5 Neutralizing Titers at 1 Month After the COVID-19 mRNA Vaccination	1392.0 Titers Interval 1256.9 to 1541.5	1063.6 Titers Interval 960.2 to 1178.2

SECONDARY outcome

Timeframe: At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants included in 1-month post vaccination timepoint and with data available for RSV-A titers at the specified timepoint were included in the analysis.

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.

Outcome measures

Outcome measures
Measure	Control Group n=365 Participants 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.	Co-Ad Group n=388 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
RSV-A Neutralizing Titers Expressed as GMT at 1 Month After RSVPreF3 OA Vaccination	8407.1 Titers Interval 7611.6 to 9285.8	8119.1 Titers Interval 7316.6 to 9009.7

SECONDARY outcome

Timeframe: 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)

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants with data available for RSV-A titers at the specified timepoints were included in the analysis.

The MGI was defined as the geometric mean of the within participant ratios of the post-vaccination titer over the pre-vaccination titer.

Outcome measures

Outcome measures
Measure	Control Group n=364 Participants 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.	Co-Ad Group n=382 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Mean Geometric Increase (MGI) of RSV-A Neutralizing Titers at 1 Month After RSVPreF3 OA Vaccination	10.21 Ratio Interval 9.2 to 11.33	8.31 Ratio Interval 7.46 to 9.26

SECONDARY outcome

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants with data available for RSV-A titers at the specified timepoints were included in the analysis.

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.

Outcome measures

Outcome measures
Measure	Control Group n=296 Participants 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.	Co-Ad Group n=282 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
RSV-A Neutralizing Titers Expressed as Seroresponse Rate (SRR) at 1 Month After RSVPreF3 OA Vaccination	81.3 Percentage of participants Interval 76.9 to 85.2	73.8 Percentage of participants Interval 69.1 to 78.2

SECONDARY outcome

Timeframe: 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)

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants with data available for RSV-A titers at the specified timepoints were included in the analysis.

Percentage of participants with RSV-A neutralizing titers \>= to the assay cut-off value (i.e. lower limit of quantification \[LLOQ\]) are presented.

Outcome measures

Outcome measures
Measure	Control Group n=389 Participants 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.	Co-Ad Group n=406 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
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 At pre-vaccination	100 Percentage of participants Interval 99.1 to 100.0	100 Percentage of participants Interval 99.1 to 100.0
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 1 month post RSVPreF3 administration	100 Percentage of participants Interval 99.0 to 100.0	100 Percentage of participants Interval 99.1 to 100.0

SECONDARY outcome

Timeframe: At 1 month post-RSVPreF3 OA vaccine dose administration (at Day 31 for Co-Ad Group and Day 61 for Control Group)

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants included in 1-month post vaccination timepoint and with data available for RSV-B titers at the specified timepoint were included in the analysis.

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.

Outcome measures

Outcome measures
Measure	Control Group n=365 Participants 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.	Co-Ad Group n=388 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
RSV-B Neutralizing Titers Expressed as GMT at 1 Month After RSVPreF3 OA Vaccination	7588.9 Titers Interval 6896.0 to 8351.5	7537.1 Titers Interval 6791.4 to 8364.5

SECONDARY outcome

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants with data available for RSV-B titers at the specified timepoints were included in the analysis.

The MGI was defined as the geometric mean of the within participant ratios of the post-vaccination titer over the pre-vaccination titer.

Outcome measures

Outcome measures
Measure	Control Group n=364 Participants 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.	Co-Ad Group n=382 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
MGI of RSV-B Neutralizing Titers at 1 Month After RSVPreF3 OA Vaccination	8.19 Ratio Interval 7.35 to 9.12	6.79 Ratio Interval 6.08 to 7.59

SECONDARY outcome

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants with data available for RSV-B titers at the specified timepoints were included in the analysis.

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.

Outcome measures

Outcome measures
Measure	Control Group n=275 Participants 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.	Co-Ad Group n=255 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
RSV-B Neutralizing Titers Expressed as SRR at 1 Month After RSVPreF3 OA Vaccination	75.5 Percentage of participants Interval 70.8 to 79.9	66.8 Percentage of participants Interval 61.8 to 71.5

SECONDARY outcome

Timeframe: 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)

Population: Analysis was performed on PPS for RSVPreF3 OA. Only participants with data available for RSV-B titers at the specified timepoints were included in the analysis.

Percentage of participants with RSV-B neutralizing titers \>= to the assay cut-off value (i.e. LLOQ) are presented.

Outcome measures

Outcome measures
Measure	Control Group n=389 Participants 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.	Co-Ad Group n=406 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
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 At pre-vaccination	100 Percentage of participants Interval 99.1 to 100.0	100 Percentage of participants Interval 99.1 to 100.0
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 1 month post RSVPreF3 administration	100 Percentage of participants Interval 99.0 to 100.0	100 Percentage of participants Interval 99.1 to 100.0

SECONDARY outcome

Timeframe: At 1 month post-COVID-19 mRNA vaccine dose administration (Day 31 for both groups)

Population: Analysis was performed on PPS for COVID-19 mRNA. Only participants included in 1-month post vaccination timepoint and with data available for SARS-CoV-2 titers at the specified timepoint were included in the analysis.

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.

Outcome measures

Outcome measures
Measure	Control Group n=388 Participants 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.	Co-Ad Group n=386 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
SARS-CoV-2 Omicron XBB.1.5 Neutralizing Titers Expressed as GMT at 1 Month After COVID-19 mRNA Vaccination	1407.3 Titers Interval 1244.5 to 1591.4	1030.4 Titers Interval 925.2 to 1147.6

SECONDARY outcome

Timeframe: 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)

Population: Analysis was performed on PPS for COVID-19 mRNA. Only participants with data available for SARS-CoV-2 Omicron XBB.1.5 neutralizing titers against the pseudovirus bearing S protein at the specified timepoints were included in the analysis.

The MGI was defined as the geometric mean of the within participant ratios of the post-vaccination titer over the pre-vaccination titer.

Outcome measures

Outcome measures
Measure	Control Group n=381 Participants 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.	Co-Ad Group n=380 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
MGI of SARS-CoV-2 Omicron XBB.1.5 Neutralizing Titers at 1 Month After COVID-19 mRNA Vaccination	5.46 Ratio Interval 4.74 to 6.3	4.25 Ratio Interval 3.73 to 4.85

SECONDARY outcome

Timeframe: At pre-vaccination (Day 1 for both groups) and at 1 month post-COVID-19 mRNA vaccine dose administration (Day 31 for both groups)

Percentage of participants with SARS-CoV-2 Omicron XBB.1.5 neutralizing titers \>= to the assay cut-off value (i.e. LLOQ) are presented.

Outcome measures

Outcome measures
Measure	Control Group n=388 Participants 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.	Co-Ad Group n=386 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
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 At pre-dose administration	94.3 Percentage of participants Interval 91.6 to 96.4	95.1 Percentage of participants Interval 92.5 to 97.0
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 1 month after COVID-19 mRNA vaccination	99.7 Percentage of participants Interval 98.6 to 100.0	99.7 Percentage of participants Interval 98.6 to 100.0

SECONDARY outcome

Timeframe: 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)

Population: Exposed set included all participants in the enrolled set who received at least 1 study intervention. Only those participants with solicited administration site AEs were included in this analysis. Analysis was reported based on each type of vaccine administered (RSVPreF3 OA vaccine and COVID-19 mRNA vaccine).

The solicited administration site events after vaccination included pain, erythema/redness, and swelling. Any = occurrence of the events regardless of the intensity grade.

Outcome measures

Outcome measures
Measure	Control Group n=411 Participants 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.	Co-Ad Group n=412 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Number of Participants Reporting Each Solicited Administration Site Event, for Each Type of Vaccine Administered Erythema, within 4 days from COVID-19 mRNA Dosing	20 Participants	19 Participants
Number of Participants Reporting Each Solicited Administration Site Event, for Each Type of Vaccine Administered Erythema, within 4 days from RSVPreF3 OA Dosing	26 Participants	34 Participants
Number of Participants Reporting Each Solicited Administration Site Event, for Each Type of Vaccine Administered Pain, within 4 days from COVID-19 mRNA Dosing	264 Participants	297 Participants
Number of Participants Reporting Each Solicited Administration Site Event, for Each Type of Vaccine Administered Pain, within 4 days from RSVPreF3 OA Dosing	235 Participants	302 Participants
Number of Participants Reporting Each Solicited Administration Site Event, for Each Type of Vaccine Administered Swelling, within 4 days from COVID-19 mRNA Dosing	13 Participants	10 Participants
Number of Participants Reporting Each Solicited Administration Site Event, for Each Type of Vaccine Administered Swelling, within 4 days from RSVPreF3 OA Dosing	9 Participants	20 Participants

SECONDARY outcome

Timeframe: 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)

Population: Analysis was performed on the Exposed set. Only those participants with solicited systemic AEs were included in this analysis. Analysis was reported based on the day of study dose administration.

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.

Outcome measures

Outcome measures
Measure	Control Group n=411 Participants 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.	Co-Ad Group n=412 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Arthralgia, within 4 days from dosing at Day 1	47 Participants	81 Participants
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Arthralgia, within 4 days from dosing at Day 31	36 Participants	—
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Fatigue, within 4 days from dosing at Day 1	115 Participants	166 Participants
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Fatigue, within 4 days from dosing at Day 31	95 Participants	—
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Fever, within 4 days from dosing at Day 1	7 Participants	26 Participants
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Fever, within 4 days from dosing at Day 31	9 Participants	—
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Headache, within 4 days from dosing at Day 1	98 Participants	120 Participants
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Headache, within 4 days from dosing at Day 31	83 Participants	—
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Myalgia, within 4 days from dosing at Day 1	117 Participants	170 Participants
Number of Participants Reporting Each Solicited Systemic Event, for Each Day of Dose Administered Myalgia, within 4 days from dosing at Day 31	91 Participants	—

SECONDARY outcome

Timeframe: 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)

Population: Analysis was performed on Exposed set.

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.

Outcome measures

Outcome measures
Measure	Control Group n=416 Participants 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.	Co-Ad Group n=417 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Number of Participants Reporting Unsolicited Adverse Events (AEs), for Each Day of Dose Administered Within 30 days after dosing at at Day 1	71 Participants	87 Participants
Number of Participants Reporting Unsolicited Adverse Events (AEs), for Each Day of Dose Administered Within 30 days after dosing at at Day 31	57 Participants	—

SECONDARY outcome

Timeframe: 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])

Population: Analysis was performed on Exposed set.

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.

Outcome measures

Outcome measures
Measure	Control Group n=416 Participants 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.	Co-Ad Group n=417 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Number of Participants Reporting Any Serious Adverse Events (SAEs)	14 Participants	16 Participants

SECONDARY outcome

Timeframe: 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])

Population: Analysis was performed on Exposed set.

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.

Outcome measures

Outcome measures
Measure	Control Group n=416 Participants 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.	Co-Ad Group n=417 Participants Participants received a single dose of RSVPreF3 OA vaccine and a single dose of COVID-19 mRNA vaccine at Day 1, in different arms.
Number of Participants Reporting Any Potential Immune-mediated Diseases (pIMDs)	1 Participants	0 Participants

Adverse Events

Co-Ad Group

Serious events: 16 serious events

Other events: 365 other events

Deaths: 0 deaths

Control Group

Serious events: 14 serious events

Other events: 337 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

GSK Response Center

GlaxoSmithKline

Phone: 866-435-7343

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee GSK agreements may vary with individual investigators, but will not prohibit any investigator from publishing. GSK supports the publication of results from all centers of a multi-center trial but requests that reports based on single site data not precede the primary publication of the entire clinical trial.
Publication restrictions are in place

Restriction type: OTHER