RSV ImmunisationPhase 3OPALNCT06705140
A Study on the Immunogenicity and Safety of 3 Different Dose Concentrations of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers
A Phase 3 study testing Low Dose (LD) RSVt vaccine, Standard Dose (SD) RSVt vaccine and High Dose (HD) RSVt vaccine in people with RSV Immunisation and Healthy Volunteers, run by Sanofi Pasteur, a Sanofi Company at 3 sites in Honduras.
Trial summary
This study was a Phase III, parallel group, randomized, observer blind, placebo controlled, multi-national, multi-center, multi-arm study conducted in 42 healthy children enrolled at 6 months to <22 months of age. Read more about this study
- Who is it for?
- Ages 6 to 21 monthsHealthy volunteers can take part
- Conditions the study is for
- RSV Immunisation, Healthy Volunteers
- What is being tested?
- Low Dose (LD) RSVt vaccine, Standard Dose (SD) RSVt vaccine and High Dose (HD) RSVt vaccine
- Type of treatment
- Vaccines
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 42 participants
- Where
- 3 sitesHonduras
- Study dates
- 25 Nov 2024to 11 Jun 2025
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 6 to 21 months
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- Aged 6 months to < 22 months on the day of inclusion (means from the day of the 6-month birthday to the day before the 22-month birthday. The second vaccine administration was administered before the study participant has turned 24 months of age).
- Participants who were healthy as determined by medical evaluation including medical history.
- For Cohort 1 and Cohort 2 (contingent upon satisfactory safety profile of the RSVt vaccine in Cohort 1):
- --Participant born 28 through 36 weeks of gestation and medically stable as assessed by the investigator, based on the following definition: "Medically stable" refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study intervention.
- For Cohort 2:
- Participant born at full term of pregnancy (≥ 37 weeks of gestation).
Who cannot join
- Participants were excluded from the study if any of the following criteria apply:
- Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
- Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study intervention used in the study or to a product containing any of the same substances.
- Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion.
- History of medically diagnosed wheezing. Children with a history of recurrent wheezing will be excluded. Children with a previous single episode of wheezing may be included if that episode of wheezing was not associated with hospitalization or if does not have a family history of wheezing.
- Any acute febrile illness in the past 48 hours that according to investigator judgment is significant enough to interfere with successful inoculation on the day of vaccination. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
Show all 23Show fewer
- Probable or confirmed ongoing case of viral respiratory infection (including COVID-19, influenza, rhinovirus, etc.) at the time of enrollment. A prospective participant should not be included in the study until the respiratory infection has resolved.
- Member of a household that contains an immunocompromised individual, including, but not limited to:
- a person who is HIV infected
- a person who has received chemotherapy within the 12 months prior to study enrollment
- a person who has received (within the past 6 months) or is receiving (at the time of enrollment) immunosuppressant agents
- a person living with a solid organ or bone marrow transplant
- Potential close contact with other immunocompromised individual within 30 days after each vaccination as per investigator's discretion.
- Participant's biological mother's previous receipt or planned administration of an investigational RSV vaccine during pregnancy and/or breastfeeding.
- Receipt or planned receipt of any of the following vaccines prior to enrollment or after the first study intervention administration:
- Any other intranasal live attenuated vaccine within the 28 days prior to and after Dose 1 study administration
- Unless given on the day of the first study intervention administration, any other injectable live attenuated vaccines within the 28 days prior to and after. Concomitant receipt on the day of the first study intervention administration is allowed
- Planned receipt of any monoclonal antibody for RSV (such as Nirsevimab or Palivizumab) for the duration of the study.
- Previous receipt of an investigational RSV vaccine or receiving any anti-RSV product (such as ribavirin or RSV immune globulin) at the time of enrollment. Previous receipt of an RSV monoclonal antibody within 6 months prior to the first study vaccine administration.
- Receipt of immune globulins, blood or blood-derived products in the past 3 months
- Receipt of intranasal and intra-ocular medications within 3 days prior to study enrollment
- Participation at the time of study enrollment or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure
- Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.
Trial locations and contacts
3 sites in 1 country.
Honduras3 sites
Investigational Site Number : 3400002
San Pedro Sula
Investigational Site Number : 3400001
Tegucigalpa, 11101
Investigational Site Number : 3400003
Tegucigalpa, 11101
About this study
Official title: A Parallel Group, Phase III, Randomized, Observer Blind, Placebo Controlled, Multi Center, Multinational, Multi Arm Study to Demonstrate Non-inferiority of the Immune Response of a Low Dose Compared to the Standard Dose and to Evaluate the Safety of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers (OPAL)
This study was a Phase III, parallel group, randomized, observer blind, placebo controlled, multi-national, multi-center, multi-arm study conducted in 42 healthy children enrolled at 6 months to <22 months of age. The purpose of the study was to evaluate the non-inferiority of the immune response of the lower dose (LD) when compared to the standard dose (SD) respiratory syncytial virus infant and toddler (RSVt) vaccine and the safety of the LD, SD and high dose (HD) vaccine in preterm born children and of the HD vaccine in full term born children administered by intranasal route and compared to placebo.
Read the detailed description
The study duration was approximately 8 months for each participant, including the 6 months safety follow-up phone call after the second study intervention administration.
- Conditions
- RSV Immunisation, Healthy Volunteers
- Being tested
- Low Dose (LD) RSVt vaccine, Standard Dose (SD) RSVt vaccine, High Dose (HD) RSVt vaccine, Placebo
- Keywords
- RSV, RSVt (RSV toddler and Infant) Vaccine
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low Dose (LD) RSVt vaccineBiological
Also called 534
Pharmaceutical form:
Liquid for nasal spray
Route of administration: Intranasal
Standard Dose (SD) RSVt vaccineBiological
Also called 534
Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
High Dose (HD) RSVt vaccineBiological
Also called 534
Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
PlaceboBiological
Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1: Group 1- (SD RSVt vaccine) | Experimental | Participants received 2 intranasal administrations of SD RSVt vaccine Receives: Biological: Standard Dose (SD) RSVt vaccine |
| Cohort 1: Group 2-Control | Placebo comparator | Participants received 2 intranasal administrations of placebo Receives: Biological: Placebo |
| Cohort 1: Group 3- (HD RSVt vaccine) | Experimental | Participants received 2 intranasal administrations of HD RSVt vaccine Receives: Biological: High Dose (HD) RSVt vaccine |
| Cohort 1: Group 4-Control | Placebo comparator | Participants received 2 intranasal administrations of placebo Receives: Biological: Placebo |
| Cohort 2: Group 1- (LD RSVt vaccine) | Experimental | Participants received 2 intranasal administrations of LD RSVt vaccine Receives: Biological: Low Dose (LD) RSVt vaccine |
| Cohort 2: Group 2- (SD RSVt vaccine) | Experimental | Participants received 2 intranasal administrations of SD RSVt vaccine Receives: Biological: Standard Dose (SD) RSVt vaccine |
| Cohort 2: Group 3- (HD RSVt vaccine | Experimental | Participants received 2 intranasal administrations of HD RSVt vaccine Receives: Biological: High Dose (HD) RSVt vaccine |
| Cohort 2: Group 4-Control | Placebo comparator | Participants received 2 intranasal administrations of placebo Receives: Biological: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cohort 2: Geometric Mean Titers (GMT) of RSV A Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)
Serum samples were planned to be collected at specified timepoints for immunogenicity assessments. RSV A serum neutralizing antibody titers were planned to be determined using a validated plaque reduction neutralization test (PRNT).
Measured: Day 85 (28 days post-vaccination 2)
Cohort 2: Geometric Mean Titers of RSV B Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)
Serum samples were planned to be collected at specified timepoints for immunogenicity assessments. RSV B serum neutralizing antibody titers were planned to be determined using a validated PRNT.
Measured: Day 85 (28 days post-vaccination 2)
Cohorts 1 and 2: Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
An AE was any untoward medical occurrence in a clinical study participant temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, i.e., pre-listed in the case report form (CRF) in terms of diagnosis and onset window post-vaccination. All participants were observed for 30 minutes after each vaccination and any unsolicited AEs that occurred during that time were recorded as immediate unsolicited AEs.
Measured: Up to 30 minutes after each vaccination (post-dose on Day 1)
Cohorts 1 and 2: Number of Participants With Solicited Administration Site Reactions
A solicited injection/administration site reactions were adverse reactions (AR) at and around the injection/administration site of the study vaccine observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF and considered as related to the study vaccine administered.
Measured: Up to 21 days after each vaccination (post-dose on Day 1)
Cohorts 1 and 2: Number of Participants With Solicited Systemic Reactions
A solicited reaction was an expected AR (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF and considered as related to the study vaccine administered.
Measured: Up to 21 days after each vaccination (post-dose on Day 1)
Cohorts 1 and 2: Number of Participants With Unsolicited Adverse Events
An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, that is, pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.
Measured: Up to 28 days after each vaccination (post-dose on Day 1)
Cohorts 1 and 2: Number of Participants With Medically Attended Adverse Events (MAAEs)
An MAAE was defined as a new onset or a worsening of a condition that prompted the participant or participant's parent/legally acceptable representative to seek unplanned medical advice at a physician's office or emergency department.
Measured: From first dose of study vaccine administration (Day 1) to 198 days
Cohorts 1 and 2: Number of Participants With Serious Adverse Events (SAEs)
An SAE was defined as any AE 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 other medically important event.
Measured: From first dose of study vaccine administration (Day 1) to 198 days
Cohorts 1 and 2: Number of Participants With Adverse Events of Special Interest (AESIs)
An AESI (serious or non-serious) was one of scientific and medical concern specific to the sponsor's study vaccine or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor was appropriate. Acute wheeze and anaphylaxis were collected as AESI.
Measured: From first dose of study vaccine administration (Day 1) to 198 days
Secondary outcomes (5)
Cohort 1: Geometric Mean Titers of RSV A and B Serum Neutralizing Antibodies at Baseline (Day 1) and Day 85
Serum samples were planned to be collected at specified timepoints for immunogenicity assessments. RSV A and RSV B serum neutralizing antibody titers were planned to be determined using a validated PRNT.
Measured: Baseline (Day 1) and Day 85
Cohorts 1 and 2: Mean Titers of RSV Serum Anti-F Immunoglobulin (Ig) A and IgG Antibodies at Baseline (Day 1) and Day 85
Serum samples were collected at specified timepoints for immunogenicity assessments. Antibodies to RSV F antigen were measured using the anti-RSV serum anti-F IgA and IgG using electrochemiluminescence method. Log10 titer values are reported.
Measured: Baseline (Day 1) and Day 85
Cohorts 1 and 2: Percentage of Participants With Quantified Shedding >=3.37 Lower Limit of Quantitation (LLOQ)
Nasal swabs were collected to assess shedding of the attenuated RSV vaccine strain at specified timepoints. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was developed to detect and quantify RSV ΔNS2 candidate in nasal swab samples. Percentages rounded off to tenth decimal place.
Measured: Day 8 and Day 64
Cohorts 1 and 2: Percentage of Participants With Detectable Shedding >=2.08 Limit of Detection
Nasal swabs were collected to assess shedding of the attenuated RSV vaccine strain at specified timepoints. qRT-PCR assay was developed to detect and quantify RSV ΔNS2 candidate in nasal swab samples. Percentages rounded off to tenth decimal place.
Measured: Day 8 and Day 64
Cohorts 1 and 2: Titer of Vaccine Virus Shedding in Participants Detected in Nasal Samples Quantified by Quantitative Real Time-Polymerase Chain Reaction
Nasal swabs were collected to assess shedding of the attenuated RSV vaccine strain at specified timepoints. qRT-PCR assay was developed to detect and quantify RSV ΔNS2 candidate in nasal swab samples. Quantified virus shedding was defined as vaccine virus shedding >=lower limit of quantification (LLOQ=3.37 log10 copies/mL).
Measured: Day 8 and Day 64
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Nov 2024
- Study start25 Nov 2024
- Primary completion11 Jun 2025
- Study completion11 Jun 2025
Why it stopped: Sponsor decision
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for RSV ImmunisationStudies of the same condition, open and under way.
- More trials run by Sanofi Pasteur, a Sanofi CompanyThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 42 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sanofi Pasteur, a Sanofi Company
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06705140
- Sponsor's protocol ID
- VAD00015
- Other IDs
- 2023-509536-26, U1111-1298-7338, 2023
- Acronym
- OPAL
- Status last verified
- Jul 2026
- First submitted
- 22 Nov 2024
- Last updated
- 3 Aug 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
Study at a glance
From the registry record, last updated by the sponsor on 3 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Parallel Group, Phase III, Randomized, Observer Blind, Placebo Controlled, Multi Center, Multinational, Multi Arm Study to Demonstrate Non-inferiority of the Immune Response of a Low Dose Compared to the Standard Dose and to Evaluate the Safety of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers (OPAL)
- ClinicalTrials.gov ID
- NCT06705140
- Acronym / sponsor ID
- OPAL / VAD00015
- Conditions
- RSV Immunisation, Healthy Volunteers
- Keywords
- RSV, RSVt (RSV toddler and Infant) Vaccine
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Sponsor decision
- Enrolment
- 42 participants (actual)
- Lead sponsor
- Sanofi Pasteur, a Sanofi CompanyIndustry (pharma, biotech, devices)
- Study start
- 25 Nov 2024 (actual)
- Primary completion
- 11 Jun 2025 (actual)
- Study completion
- 11 Jun 2025 (actual)
- First posted
- 26 Nov 2024 (actual)
- Results
- Posted 3 Aug 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study was a Phase III, parallel group, randomized, observer blind, placebo controlled, multi-national, multi-center, multi-arm study conducted in 42 healthy children enrolled at 6 months to <22 months of age. The purpose of the study was to evaluate the non-inferiority of the immune response of the lower dose (LD) when compared to the standard dose (SD) respiratory syncytial virus infant and toddler (RSVt) vaccine and the safety of the LD, SD and high dose (HD) vaccine in preterm born children and of the HD vaccine in full term born children administered by intranasal route and compared to placebo.
Detailed description
The study duration was approximately 8 months for each participant, including the 6 months safety follow-up phone call after the second study intervention administration.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 8
| Arm | Type | Receives |
|---|---|---|
| Cohort 1: Group 1- (SD RSVt vaccine) | Experimental | Biological: Standard Dose (SD) RSVt vaccineParticipants received 2 intranasal administrations of SD RSVt vaccine |
| Cohort 1: Group 2-Control | Placebo comparator | Biological: PlaceboParticipants received 2 intranasal administrations of placebo |
| Cohort 1: Group 3- (HD RSVt vaccine) | Experimental | Biological: High Dose (HD) RSVt vaccineParticipants received 2 intranasal administrations of HD RSVt vaccine |
| Cohort 1: Group 4-Control | Placebo comparator | Biological: PlaceboParticipants received 2 intranasal administrations of placebo |
| Cohort 2: Group 1- (LD RSVt vaccine) | Experimental | Biological: Low Dose (LD) RSVt vaccineParticipants received 2 intranasal administrations of LD RSVt vaccine |
| Cohort 2: Group 2- (SD RSVt vaccine) | Experimental | Biological: Standard Dose (SD) RSVt vaccineParticipants received 2 intranasal administrations of SD RSVt vaccine |
| Cohort 2: Group 3- (HD RSVt vaccine | Experimental | Biological: High Dose (HD) RSVt vaccineParticipants received 2 intranasal administrations of HD RSVt vaccine |
| Cohort 2: Group 4-Control | Placebo comparator | Biological: PlaceboParticipants received 2 intranasal administrations of placebo |
Who may qualify
- Ages
- 6 to 21 months
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (6 listed)
- Aged 6 months to < 22 months on the day of inclusion (means from the day of the 6-month birthday to the day before the 22-month birthday. The second vaccine administration was administered before the study participant has turned 24 months of age).
- Participants who were healthy as determined by medical evaluation including medical history.
- For Cohort 1 and Cohort 2 (contingent upon satisfactory safety profile of the RSVt vaccine in Cohort 1):
- --Participant born 28 through 36 weeks of gestation and medically stable as assessed by the investigator, based on the following definition: "Medically stable" refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study intervention.
- For Cohort 2:
Key exclusion criteria (23 listed)
- Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
- Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study intervention used in the study or to a product containing any of the same substances.
- Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion.
- History of medically diagnosed wheezing. Children with a history of recurrent wheezing will be excluded. Children with a previous single episode of wheezing may be included if that episode of wheezing was not associated with hospitalization or if does not have a family history of wheezing.
- Any acute febrile illness in the past 48 hours that according to investigator judgment is significant enough to interfere with successful inoculation on the day of vaccination. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Low Dose (LD) RSVt vaccineAlso: 534Pharmaceutical form: Liquid for nasal spray Route of administration: Intranasal | Biological | Cohort 2: Group 1- (LD RSVt vaccine) |
| Standard Dose (SD) RSVt vaccineAlso: 534Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal | Biological | Cohort 1: Group 1- (SD RSVt vaccine), Cohort 2: Group 2- (SD RSVt vaccine) |
| High Dose (HD) RSVt vaccineAlso: 534Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal | Biological | Cohort 1: Group 3- (HD RSVt vaccine), Cohort 2: Group 3- (HD RSVt vaccine |
| PlaceboPharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal | Biological | Cohort 1: Group 2-Control, Cohort 1: Group 4-Control, Cohort 2: Group 4-Control |
Primary outcome
Cohort 2: Geometric Mean Titers (GMT) of RSV A Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)
Time frame: Day 85 (28 days post-vaccination 2)
Serum samples were planned to be collected at specified timepoints for immunogenicity assessments. RSV A serum neutralizing antibody titers were planned to be determined using a validated plaque reduction neutralization test (PRNT).
Cohort 2: Geometric Mean Titers of RSV B Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)
Time frame: Day 85 (28 days post-vaccination 2)
Serum samples were planned to be collected at specified timepoints for immunogenicity assessments. RSV B serum neutralizing antibody titers were planned to be determined using a validated PRNT.
Cohorts 1 and 2: Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
Time frame: Up to 30 minutes after each vaccination (post-dose on Day 1)
An AE was any untoward medical occurrence in a clinical study participant temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, i.e., pre-listed in the case report form (CRF) in terms of diagnosis and onset window post-vaccination. All participants were observed for 30 minutes after each vaccination and any unsolicited AEs that occurred during that time were recorded as immediate unsolicited AEs.
Cohorts 1 and 2: Number of Participants With Solicited Administration Site Reactions
Time frame: Up to 21 days after each vaccination (post-dose on Day 1)
A solicited injection/administration site reactions were adverse reactions (AR) at and around the injection/administration site of the study vaccine observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF and considered as related to the study vaccine administered.
Cohorts 1 and 2: Number of Participants With Solicited Systemic Reactions
Time frame: Up to 21 days after each vaccination (post-dose on Day 1)
A solicited reaction was an expected AR (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF and considered as related to the study vaccine administered.
Cohorts 1 and 2: Number of Participants With Unsolicited Adverse Events
Time frame: Up to 28 days after each vaccination (post-dose on Day 1)
An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, that is, pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.
Cohorts 1 and 2: Number of Participants With Medically Attended Adverse Events (MAAEs)
Time frame: From first dose of study vaccine administration (Day 1) to 198 days
An MAAE was defined as a new onset or a worsening of a condition that prompted the participant or participant's parent/legally acceptable representative to seek unplanned medical advice at a physician's office or emergency department.
Cohorts 1 and 2: Number of Participants With Serious Adverse Events (SAEs)
Time frame: From first dose of study vaccine administration (Day 1) to 198 days
An SAE was defined as any AE 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 other medically important event.
Cohorts 1 and 2: Number of Participants With Adverse Events of Special Interest (AESIs)
Time frame: From first dose of study vaccine administration (Day 1) to 198 days
An AESI (serious or non-serious) was one of scientific and medical concern specific to the sponsor's study vaccine or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor was appropriate. Acute wheeze and anaphylaxis were collected as AESI.
5 secondary outcomes
Cohort 1: Geometric Mean Titers of RSV A and B Serum Neutralizing Antibodies at Baseline (Day 1) and Day 85
Time frame: Baseline (Day 1) and Day 85
Cohorts 1 and 2: Mean Titers of RSV Serum Anti-F Immunoglobulin (Ig) A and IgG Antibodies at Baseline (Day 1) and Day 85
Time frame: Baseline (Day 1) and Day 85
Cohorts 1 and 2: Percentage of Participants With Quantified Shedding >=3.37 Lower Limit of Quantitation (LLOQ)
Time frame: Day 8 and Day 64
Cohorts 1 and 2: Percentage of Participants With Detectable Shedding >=2.08 Limit of Detection
Time frame: Day 8 and Day 64
Cohorts 1 and 2: Titer of Vaccine Virus Shedding in Participants Detected in Nasal Samples Quantified by Quantitative Real Time-Polymerase Chain Reaction
Time frame: Day 8 and Day 64
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Aug 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- VAD00015 Plain Language Results SummaryLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
Related trials for RSV Immunisation
RecruitingPhase 4
Immunogenicity and Safety of Respiratory Syncytial Virus Vaccine in Lung Transplant Recipients
Vaccination, Respiratory Syncytial Virus (RSV)
Active, not recruitingPhase 1/2
Safety and Immunogenicity Study of SCB-1022 and SCB-1033 in Healthy Older Adults
RSV Infection, Human Metapneumovirus Infection
RecruitingObservational study
Real-World Effectiveness of Perinatal RSV Immunoprophylaxis
RSV Infection
RecruitingPhase 4
Concurrent Versus Sequential Administration of Tdap and RSV Vaccines in Pregnancy
RSV, Tdap - Tetanus, Diphtheria and Acellular Pertussis Vaccination
Not yet recruitingObservational study
Assessment of the Acceptability of, and Factors Associated With, Recommended Vaccinations During Pregnancy in Maternity Units in the Ile-de-France Region
Vaccination Coverage Among Pregnant Women
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Low Dose (LD) RSVt vaccine, Standard Dose (SD) RSVt vaccine and High Dose (HD) RSVt vaccine in people with RSV Immunisation and Healthy Volunteers, run by Sanofi Pasteur, a Sanofi Company at 3 sites in Honduras.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 23 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 3 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Honduras. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 3 Aug 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cohort 2: Geometric Mean Titers (GMT) of RSV A Serum Neutralizing Antibodies at Day 85 (Post-Dose 2) (time frame: Day 85 (28 days post-vaccination 2)). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Aug 2026.