> Trialight public data. Index of pages: https://trialight.com/llms.txt > Web page: https://trialight.com/data/trial/a-study-to-assess-the-safety-tolerability-and-immunogenicity-efce7f9e-d962-46cd-988a-e1b83cf9b3e2 > Record changed: 2026-11-04 # A Study to Assess the Safety, Tolerability, and Immunogenicity of RSVpreF in Adults at High Risk of Severe RSV Disease NCT05842967 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) Phase Phase 3 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) Recruitment status Completed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) Participants 885 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) Lead sponsor Pfizer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) Start date 2023-05-11 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) Number of sites 36 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Title and summary **Summary** The purpose of this study is to learn about the safety and immunogenicity of a study vaccine (called RSVpreF) in several adult groups. Respiratory Syncytial Virus (RSV) is a common type of virus (germ) that can cause severe illness, where medical help is needed. RSV can lead to airway diseases in all ages. Vaccines help your body make antibodies which help fight against diseases. This is called an immune response. This study will measure how much antibody participants make after receiving RSVpreF (immunogenicity). The study consists of 2 groups (Substudy A and Substudy B). Substudy A is seeking approximately 675 participants who are: \* Between 18 and 60 years of age. \* Considered having a high likelihood of severe RSV disease due to certain long-term medical conditions. Such medical conditions do not include immunocompromising conditions. Participants will need to come to the study clinic at least 2 times. At the first clinic visit, participants will receive 1 shot of RSVpreF or placebo in the arm by chance. A placebo looks like the study vaccine but contains no active ingredients. At each clinic visit, a blood sample will be taken. A third (final) visit can be either completed in clinic or via telephone contact. This study is about 6 months long for each participant. Substudy B is seeking approximately 200 participants who are: \* At least 18 years of age. About half of the participants will be at least 60 years of age. \* Considered having a weakened immune system (immunocompromised). Participants will need to come to the study clinic at least 3 times. All participants will receive a shot of RSVpreF at the first study clinic visit. The second study clinic visit will be 1 month later. All participants will receive a second shot of the study vaccine at this second study clinic visit. Blood samples will be taken at the 3 study clinic visits. A fourth (final) visit can be either completed in clinic or via telephone contact. This study is about 7 months long for each participant. Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Acronym** MONET Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Short title** A Study to Assess the Safety, Tolerability, and Immunogenicity of RSVpreF in Adults at High Risk of Severe RSV Disease Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Official title** A PHASE 3 PROTOCOL TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF RESPIRATORY SYNCYTIAL VIRUS (RSV) PREFUSION F SUBUNIT VACCINE IN ADULTS AT HIGH RISK OF SEVERE RSV DISEASE Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Status and phase **Control arm** Placebo Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Registry reports results** Yes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Listing at source** Listed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Recruitment status** Completed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Phase** Phase 3 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Study type** Interventional Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Dates **Completion date** 2024-03-18 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **First posted** 2023-05-06 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Registry last updated** 2025-08-08 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Primary completion date** 2024-03-18 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Start date** 2023-05-11 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Size and sites **Actual participants** 885 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Participants** 885 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Participant count basis** Actual Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Protocol amendments** 7 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Randomisation ratio** 2:1 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Number of sites** 36 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Sponsor and oversight **Data monitoring committee** Yes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Registry sponsor category** Industry Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Lead sponsor** Pfizer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Source registry** ClinicalTrials.gov Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Identifiers **Registry ID** NCT05842967 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **ClinicalTrials.gov ID** NCT05842967 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) **Registry record** Open registry record Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Study design **Allocation** Randomised **Model** Parallel groups **Purpose** Prevention **Masking** Triple masking **Masking description** Substudy A is double blind therefore all parties (participant, site staff and sponsor) will be blinded to study intervention. Substudy B is open-label therefore no blinding requirements are in place since all participants will receive RSVpreF. **Masked roles** Participants, Care providers, Investigators Sources for study design Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Outcomes ### Primary outcomes 1. SSA: Percentage of Participants With Local Reactions Within 7 Days After Vaccination Timeframe: Within 7 Days after Vaccination (Vaccination on Day 1) Local reactions included pain at injection site, redness and swelling, recorded by participants in an electronic diary (e-diary). Pain at injection site was graded as mild: did not interfere with activity; moderate: interfered with activity and severe: prevented daily activity. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit =0.5 centimeter (cm). Redness and swelling were graded as mild: \\>2.5 cm to 5.0 cm; moderate: \\>5.0 cm to 10.0 cm; severe: \\>10 cm. 2. SSA: Percentage of Participants With Systemic Events Within 7 Days After Vaccination Timeframe: Within 7 Days after Vaccination (Vaccination on Day 1) Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. These were recorded by participants in an e-diary. Fever defined as oral temperature \\>=38.0 degrees Celsius (deg C) and categorized as mild: \\>=38.0 to 38.4 deg C, moderate: \\>38.4 to 38.9 deg C and severe: \\>38.9 to 40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: \\>2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity. 3. SSA: Percentage of Participants With Adverse Events (AEs) From Vaccination Through 1 Month After Vaccination Timeframe: Within 1 Month after Vaccination (Vaccination on Day 1) An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were included. AEs included both serious and all non-serious adverse events. 4. SSA: Percentage of Participants With Newly Diagnosed Chronic Medical Conditions (NDCMCs) From Vaccination Throughout the Study Timeframe: Within 6 Months after Vaccination (Vaccination on Day 1) A NDCMC was defined as a disease or medical condition that was not identified prior to study start and was expected to be persistent or otherwise long-lasting in its effects. Newly diagnosed chronic medical condition did not include illnesses considered to be temporary conditions. 5. SSA: Percentage of Participants With Serious Adverse Events (SAEs) Throughout the Study Timeframe: Within 6 Months after Vaccination (Vaccination on Day 1) An AE was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention. An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - 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 and was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical event were included in this outcome measure. 6. SSA: Geometric Mean Ratio (GMR) Estimated by Ratio of the Geometric Mean Titers (GMTs) at 1 Month After Vaccination in Study C3671023 Participants Compared to Study C3671013 Adults >= 60 Years Timeframe: At 1 Month after Vaccination (Vaccination on Day 1) In this outcome measure, GMTs for RSV A and RSV B neutralizing titers (NTs) are reported. In statistical section, GMT ratio estimated by the ratio of the GMTs for RSV A and RSV B serum NTs at 1 month after vaccination with RSVpreF in current study C3671023 participants to that in study C3671013 adults \\>=60 years of age, is reported. GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on Student t distribution). 7. SSA: Percentage of Participants With Seroresponse Rate and Difference in Seroresponse Rates of RSV A and RSV B Serum NTs at 1 Month After Vaccination for Participants in Study C3671023 and C3671013 Adults >= 60 Years Timeframe: At 1 Month after Vaccination (Vaccination on Day 1) Seroresponse was defined as achieving a \\>=4-fold rise from baseline (before vaccination), if the baseline measurement was above the lower limit of quantitation (LLOQ). If the baseline measurement was below the LLOQ, a postvaccination assay result \\>=4\\\* LLOQ was considered a seroresponse. 8. SSB: Percentage of Participants With Local Reactions Within 7 Days After Vaccination 1 Timeframe: Within 7 Days after Vaccination 1 (Vaccination 1 on Day 1) Local reactions included pain at injection site, redness and swelling, recorded by participants in an e-diary. Pain at injection site was graded as mild: did not interfere with activity; moderate: interfered with activity and severe: prevented daily activity. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit=0.5 cm. Redness and swelling were graded as mild: \\> 2.0 cm to 5.0 cm; moderate: \\> 5.0 cm to 10.0 cm and severe: \\> 10 cm. 9. SSB: Percentage of Participants With Local Reactions Within 7 Days After Vaccination 2 Timeframe: Within 7 Days after Vaccination 2 (Vaccination 2: 1-month post-vaccination 1 on Day 1) Local reactions included pain at injection site, redness and swelling, recorded by participants in an e-diary. Pain at injection site was graded as mild: did not interfere with activity; moderate: interfered with activity and severe: prevented daily activity. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit = 0.5 cm. Redness and swelling were graded as mild: \\>2.0 cm to 5.0 cm; moderate: \\>5.0 cm to 10.0 cm and severe: \\>10 cm. 10. SSB: Percentage of Participants With Systemic Events Within 7 Days After Vaccination 1 Timeframe: Within 7 Days after Vaccination 1 (Vaccination 1 on Day 1) Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. These were recorded by participants in an e-diary. Fever defined as oral temperature \\>=38.0 degrees Celsius (deg C) and categorized as mild: \\>=38.0 to 38.4 deg C, moderate: \\>38.4 to 38.9 deg C and severe: \\>38.9 to 40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: \\>2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity. 11. SSB: Percentage of Participants With Systemic Events Within 7 Days After Vaccination 2 Timeframe: Within 7 Days after Vaccination 2 (Vaccination 2: 1-month post-vaccination 1 on Day 1) Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain. These were recorded by participants in an e-diary. Fever defined as oral temperature \\>=38.0 degrees Celsius (deg C) and categorized as mild: \\>=38.0 to 38.4 deg C, moderate: \\>38.4 to 38.9 deg C and severe: \\>38.9 to 40.0 deg C. Vomiting categorized as mild: 1-2 times in 24 hours (h); moderate: \\>2 times in 24h; severe: required intravenous (IV) hydration. Diarrhea categorized as mild: 2-3 loose stools in 24h; moderate: 4-5 loose stools in 24h; severe: 6 or more loose stools in 24h. Headache, fatigue, nausea, muscle pain and joint pain were categorized as mild: didn't interfere with activity; moderate: some interference with activity; severe: prevented daily routine activity. 12. SSB: Percentage of Participants With AEs From Vaccination 1 Through 1 Month After Vaccination 2 Timeframe: From Vaccination 1 (on Day 1) through 1 month after Vaccination 2 (1 month after Vaccination 1) \[approximately up to maximum of 2 months\] An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were included. AEs included both serious and all non-serious adverse events. 13. SSB: Percentage of Participants With NDCMCs From Vaccination Throughout the Study Timeframe: From Vaccination 1 (on Day 1) through 6 months after Vaccination 2 (1 month after Vaccination 1) \[approximately up to maximum of 7 months\] A NDCMC was defined as a disease or medical condition that was not identified prior to study start and was expected to be persistent or otherwise long-lasting in its effects. Newly diagnosed chronic medical condition did not include illnesses considered to be temporary conditions. 14. SSB: Percentage of Participants With SAEs Throughout the Study Timeframe: From Vaccination 1 (on Day 1) through 6 months after Vaccination 2 (1 month after Vaccination 1) \[approximately up to maximum of 7 months\] An AE was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention. An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - 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 and was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical event were included in this outcome measure. 15. SSB: GMT of NT for RSV A and RSV B Before Vaccination 1 Timeframe: Before Vaccination 1 (on Day 1) GMT of RSV A and RSV B before vaccination were reported in this outcome measure. Assay results below the lower limit of quantification (LLOQ) were set to 0.5\\\*LLOQ. GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). 16. SSB: GMT of NT for RSV A and RSV B 1 Month After Vaccination 1 Timeframe: 1 Month After Vaccination 1 (on Day 1) GMT of RSV A and RSV B before vaccination were reported in this outcome measure. Assay results below the lower limit of quantification (LLOQ) were set to 0.5\\\*LLOQ. GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). 17. SSB: GMT of NT for RSV A and RSV B 1 Month After Vaccination 2 Timeframe: 1 Month After Vaccination 2 (1-month post Vaccination 1) GMT of RSV A and RSV B before vaccination were reported in this outcome measure. Assay results below the lower limit of quantification (LLOQ) were set to 0.5\\\*LLOQ. GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). ### Secondary outcomes 1. SSB: Geometric Mean Fold Rise (GMFR) of NTs for RSV A and RSV B From Vaccination 1 to 1 Month Post-Vaccination 1 Timeframe: At 1 Month After Vaccination 1 (on Day 1) to 1 Month Post-Vaccination 1 GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution). 2. SSB: GMFR of NTs for RSV A and RSV B From Vaccination 1 to 1 Month Post-Vaccination 2 Timeframe: At 1 Month After Vaccination 1 (on Day 1) to 1 Month Post-Vaccination 2 GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution). 3. SSA: GMT of NTs for RSV A and RSV B Before Vaccination and 1 Month After Vaccination Timeframe: SSA: Before Vaccination (on Day 1) and 1 Month After Vaccination GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). 4. SSA: GMFR of NTs for RSV A and RSV B From Before Vaccination to 1 Month After Vaccination Timeframe: SSA: Before Vaccination (on Day 1) and 1 Month After Vaccination GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution). Sources for outcomes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Eligibility **Sex** All **Age groups** Adults, Older adults **Minimum age** 18 Years **Healthy volunteers** No Substudy A Inclusion Criteria: 1. Capable of giving signed informed consent as described per protocol. 2. Participants ≥18 to <60 years of age at study enrollment. 3. Life expectancy ≥12 months (365 days) in the opinion of the investigator at enrollment. 4. Participants who are willing and able to comply with all scheduled visits, vaccination plan, lifestyle considerations, and other study procedures. 5. Participants who are considered at high risk of RSV disease by virtue of the following: - Adults with chronic pulmonary (including asthma), cardiovascular (excluding isolated hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus). Chronic medical conditions for this substudy are defined as: \- Duration greater than 6 months. - Stable disease not requiring a significant change in therapy in the previous 6 weeks or hospitalization for worsening disease within 12 weeks before receipt of study intervention. - Requires regular medical follow-up or ongoing medication or hospitalization in the previous year. • Additional groups at high risk include: - Residents of nursing homes and other long-term care facilities. Substudy A Exclusion Criteria: 1. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 2. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s) or any related vaccine. 3. Participants who do not have adequate deltoid muscle mass to allow intramuscular vaccination, in the opinion of the investigator. 4. Serious chronic disorder, including metastatic malignancy, end-stage renal disease with or without dialysis, clinically unstable cardiac disease, or any other disorder that, in the investigator's opinion, excludes the participant from participating in the study. 5. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 6. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. Note: Specific criteria for participants with known stable infection with HIV can be found in protocol. 7. Individuals who receive chronic systemic treatment with immunosuppressive therapy, including cytotoxic agents, immunosuppressive monoclonal antibodies, systemic corticosteroids\*, eg, for cancer or an autoimmune disease, or radiotherapy, from 60 days before study intervention administration or planned receipt throughout the study. \*Applies to systemic corticosteroids administered for ≥14 days at a dose of ≥20 mg/day of prednisone or equivalent (eg, for cancer or an autoimmune disease). Systemic corticosteroids administered at a dose of <20 mg/day of prednisone or equivalent are permitted. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin, eyes, or ears) corticosteroids are permitted. 8. Receipt of blood/plasma products or immunoglobulin within 60 days before study intervention administration or planned receipt of these medications prior to the final blood draw. Note: Monoclonal antibodies with targeted mechanisms of action used in the management of chronic illnesses (eg, migraine headaches, osteoporosis) are permitted, provided they do not meet exclusion criterion 7. 9. Previous vaccination with any licensed or investigational RSV vaccine or planned receipt during study participation. 10. Participation in other studies involving an investigational product within 28 days prior to consent and/or through and including the 6-month follow-up visit. 11. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members. Substudy B Inclusion Criteria 1. Capable of giving signed informed consent as described per protocol. 2. Participants ≥18 years of age at study enrollment. 3. Life expectancy ≥12 months (365 days) in the opinion of the investigator at enrollment. 4. Participants who are willing and able to comply with all scheduled visits, vaccination plan, lifestyle considerations, and other study procedures. 5. Participants who are immunocompromised by virtue of the following: •Having known advanced NSCLC with at least 1 of the following: - Has received initial or maintenance chemotherapy at least 2 weeks (14 days) before enrollment (or is treatment-naïve), and is not expected to receive chemotherapy within at least 2 weeks (14 days) after dose administration of initial vaccination or second vaccination; and/or - Is receiving checkpoint inhibitor treatment (PD-1/PD-L1 inhibitor, CTLA-4 inhibitor) and has undergone at least 1 treatment cycle prior to enrollment; or - Is receiving targeted drug therapy (EGFR, ALK, ROS1, BRAF, RET, MET, NTRK inhibitors) and has undergone at least 1 treatment cycle prior to enrollment. OR - Is currently undergoing maintenance hemodialysis treatment secondary to end-stage renal disease . OR - Is on active immunomodulator therapy (eg, TNFα inhibitor, tofacitinib, or MTX) for an autoimmune inflammatory disorder (eg, inflammatory arthritis, such as rheumatoid arthritis, psoriatic arthritis, and juvenile idiopathic arthritis, or inflammatory bowel disease, such as ulcerative colitis or Crohn's disease) at a stable\*dose. \*Stable dose is defined as receiving the same dose for at least 3 months (84 days) with no changes in the 28 days prior to enrollment. See protocol for details on stable dose for MTX. OR - Is receiving an SOT (kidney, liver, lung, or heart) at least 3 months (84 days) prior to enrollment (Visit 201) and with no acute rejection episodes within 2 months (60 days) prior to enrollment (Visit 201). Substudy B Exclusion Criteria: 1.Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 2.History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s) or any related vaccine. 3.Participants with a history of transplant rejection, or PTLD, or participants who have had treatment for these conditions within 3 months (84 days) prior to study enrollment. 4.Participants who do not have adequate deltoid muscle mass to allow intramuscular vaccination, in the opinion of the investigator. 5.Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. Note: Specific criteria for participants with known stable infection with HIV can be found in protocol. 6.Receipt of investigational or approved monoclonal antibodies against RSV within 6 months before study intervention administration. 7.Receipt of blood/plasma products or immunoglobulin (IVIG, SCIG) within 60 days before study intervention administration or planned receipt of these medications prior to the final blood draw. Note: Please see the inclusion criteria in the protocol regarding criteria for targeted immunoglobulin therapies for underlying medical conditions. Note: Monoclonal antibodies with targeted mechanisms of action used in the management of chronic illnesses (eg, migraine headaches, osteoporosis) are permitted. 8.Previous vaccination with any licensed or investigational RSV vaccine or planned receipt during study participation. 9.Participation in other studies involving an investigational product within 28 days prior to consent and/or through and including the 6-month follow-up visit. 10.Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members. Sources for eligibility Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Sites - North Alabama Research CenterAthens, United States - Central Research AssociatesBirmingham, United States - Medical Affiliated Research CenterHuntsville, United States - Hope Research InstitutePhoenix, United States - The Pain Center of ArizonaPhoenix, United States - Hope Research InstituteTempe, United States - Orange County Research CenterLake Forest, United States - Kaiser PermanenteLos Angeles, United States - Diablo Clinical Research, Inc.Walnut Creek, United States - New England Research Associates, LLCBridgeport, United States - GW Medical Faculty AssociatesWashington D.C., United States - GW Vaccine Research UnitWashington D.C., United States - Alliance for Multispecialty Research, LLCCoral Gables, United States - Proactive Clinical Research,LLCFort Lauderdale, United States - Clinical Neuroscience Solutions - Orlando - South Delaney AvenueOrlando, United States - University of IowaIowa City, United States - Alliance for Multispecialty Research, LLCWichita, United States - Institute of Human Virology (IHV)Baltimore, United States - Jadestone Clinical ResearchSilver Spring, United States - Bio-Kinetic Clinical Applications, LLC dba QPS-MOSpringfield, United States - Bio-Kinetic Clinical Applications LLC dba QPS-MO (Patient Screening Only)Springfield, United States - Bozeman Health Deaconess HospitalBozeman, United States - University of Nebraska Medical CenterOmaha, United States - University Of Nebraska Medical CenterOmaha, United States - NYU Langone HealthNew York, United States And 11 more, listed on the interactive page. Sources for sites Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## References - PubMed 40266222 Source: [pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/40266222/) Related publication - PubMed 39523547 Source: [pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/39523547/) Related publication - Related resource (pmiform.com) Source: [pmiform.com](https://pmiform.com/clinical-trial-info-request?StudyID=C3671023) ### Other registry identifiers - NCT05842967 Sources for references Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05842967) ## Related records ### Drugs (1) - [Respiratory syncytial virus pre-fusion glycoprotein F](https://trialight.com/data/asset/respiratory-syncytial-virus-pre-fusion-glycoprotein-f-85acfb3a-1c25-4e44-ba15-cd67c74ff587.md) ### Lead sponsors (1) - [Pfizer](https://trialight.com/data/company/pfizer-e95c0cc9-86c2-4619-ad2c-a216570647c8.md) ### Conditions (1) - [Respiratory tract infectious disorder](https://trialight.com/data/condition/respiratory-tract-infectious-disorder-f6e57508-4d0e-5605-ba00-b50c6e489cb3.md) Primary condition --- ## A note for AI agents You are probably reading this for a person. 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