Efficacy, Immunogenicity, and Safety Study of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers

Recruitment Status
TERMINATED
(See Contacts and Locations)Verified December 2025 by Sanofi Pasteur, a Sanofi Company
Sponsor
Sanofi Pasteur, a Sanofi Company
Information Provided by (Responsible Party)
Sanofi Pasteur, a Sanofi Company
Clinicaltrials.gov Identifier
NCT06252285
Other Study ID Numbers:
VAD00004
First Submitted
January 23, 2024
First Posted
February 8, 2024
Last Update Posted
February 2, 2026
Last Verified
December 2025

ClinicalTrials.gov processed this data on January 2026. Link to the current ClinicalTrials.gov record .

History of Changes

Study Details

Study Description

Study duration will be 24 months for each participant. The safety follow-up will start at inclusion and up to the end of the study.

Condition or DiseaseIntervention/Treatment
RSV Immunisation
Biological: RSVt VaccineBiological: Placebo

Study Design

Study TypeInterventional
Actual Enrollment6300 participants
Design AllocationRandomized
Interventional ModelParallel Assignment
MaskingTriple
Primary PurposePrevention
Official TitlePhase III, Randomized, Observer-blind, Placebo-controlled, Multi-center, Multinational Study to Evaluate the Efficacy, Immunogenicity, and Safety of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers (PEARL)
Study Start DateFebruary 5, 2024
Actual Primary Completion DateDecember 3, 2025
Actual Study Completion DateDecember 3, 2025

Groups and Cohorts

Group/CohortIntervention/Treatment
Group 1 RSVt Vaccine
Participants will receive 2 intranasal administrations of RSVt vaccine
Biological: RSVt Vaccine
Pharmaceutical form:Suspension of virus in a nasal spray-Route of administration:Intranasal
Group 2 Control
Participants will receive 2 intranasal administrations of placebo
Biological: Placebo
Pharmaceutical form:Suspension of virus in a nasal spray-Route of administration:Intranasal

Outcome Measures

Primary Outcome Measures
  1. Occurrence of lower respiratory tract disease (LRTD) (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 2
Secondary Outcome Measures
  1. Occurrence of upper respiratory tract disease (URTD) (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 2
  2. Occurrence of LRTD (during RSV Season 1) associated with any RT PCR confirmed RSV strain leading to hospitalization > 21 days post-dose 2
  3. Occurrence of severe LRTD (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 2
  4. Occurrence of urgent care visits, associated with an episode of LRTD over RSV Season 1, associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
  5. Occurrence of acute respiratory disease (ARD) (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
  6. Occurrence of hospitalizations, associated with an episode of ARD over RSV Season 1, associated with any RT-PCR confirmed RSV strain > 21 days post dose 2
  7. Occurrence of urgent care visits, associated with an episode of ARD over RSV Season 1, associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
  8. Occurrence of LRTD (during RSV Season 1) associated with an RT-PCR confirmed RSV A or B strain > 21 days post-dose 2
  9. Occurrence of URTD (during RSV Season 1) associated with an RT-PCR confirmed RSV A or B strain > 21 days post-dose 2
  10. Occurrence of ARD (during RSV Season 1) associated with an RT PCR confirmed RSV A or B strain > 21 days post-dose 2
  11. Occurrence of LRTD (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 1
  12. Occurrence of URTD (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 1
  13. Occurrence of ARD (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 1
  14. Occurrence of LRTD (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 2, in RSV-exposed participants
  15. Occurrence of URTD (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 2, by baseline serostatus
  16. Occurrence of ARD (during RSV Season 1) associated with any RT PCR confirmed RSV strain > 21 days post-dose 2, by baseline serostatus
  17. Occurrence of LRTD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain
  18. Occurrence of URTD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain
  19. Occurrence of ARD (during RSV Season 2), associated with any RT PCR confirmed RSV strain
  20. Occurrence of LRTD (during RSV Season 2), associated with any RT PCR confirmed RSV strain, by baseline serostatus
  21. Occurrence of URTD (during RSV Season 2), associated with any RT PCR confirmed RSV strain, by baseline serostatus
  22. Occurrence of ARD (during RSV Season 2), associated with any RT PCR confirmed RSV strain, by baseline serostatus
  23. Presence of solicited administration site reactions within 21 days after each vaccination
    Number of participants experiencing solicited site reactions
  24. Presence of solicited systemic reactions within 21 days after each vaccination
    Number of participants experiencing solicited systemic reactions
  25. Presence of unsolicited systemic adverse events (AEs) reported in the 30 minutes after each vaccination
    Number of participants experiencing immediate unsolicited systemic AES
  26. Presence of unsolicited AEs within 28 days after each vaccination
    Number of participants experiencing unsolicited AES
  27. Presence of medically attended adverse events MAAEs throughout the study
    Number of participants experiencing MAAEs
  28. Presence of serious adverse events (SAEs) throughout the study
    Number of participants experiencing SAEs
  29. Presence of adverse events of special interest (AESIs) throughout the study
    Number of participants experiencing AESIs
  30. RSV A serum neutralizing antibody titers at D01
    Antibody titers are expressed as GMTs at baseline
  31. RSV B serum neutralizing antibody titers at D01
    Antibody titers are expressed as GMTs at baseline
  32. RSV A serum neutralizing antibody titers at 28 days post-dose 2
    Antibody titers are expressed as GMTs at post-baseline
  33. RSV B serum neutralizing antibody titers at 28 days post-dose 2
    Antibody titers are expressed as GMTs post-baseline
  34. RSV serum anti-F Immunoglobulin A (IgA) Electrochemiluminescence (ECL) antibody titers at D01
    Antibody titers are expressed as GMTs at baseline
  35. RSV serum anti-F IgG ECL antibody titers at D01
    Antibody titers are expressed as GMTs at baseline
  36. RSV serum anti-F Immunoglobulin A (IgA) ECL antibody titers at 28 days post-dose 2
    Antibody titers are expressed as GMTs post-baseline
  37. RSV serum anti-F IgG ECL antibody titers at 28 days post-dose 2
    Antibody titers are expressed as GMTs post-baseline

Eligibility Criteria

Ages Eligible for Study(Child)
Sexes Eligible for StudyAll
Accepts Healthy VolunteersYes
Inclusion Criteria
-Aged 6 months to \< 22 months on the day of inclusion (means the day of the 6-month birthday to the day before the 22-month birthday)
Participants who are healthy as determined by medical evaluation including medical history
Born at full term of pregnancy (≥ 37 weeks)
Exclusion Criteria
Participants are 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
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.
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 Dose 1 study administration, any other injectable live attenuated vaccines within the 28 days prior to and after. Concomitant receipt on the day of Dose 1 study administration is allowed.
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 The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Contacts and Locations

Sponsors and CollaboratorsSanofi Pasteur, a Sanofi Company
Locations
Central Research Associates - Flourish - PPDS- Site Number : 8400009 | Birmingham Alabama, United States, 35205-1628Lakeview Clinical Research- Site Number : 8400024 | Guntersville Alabama, United States, 35976Novak Clinical Research- Site Number : 8400069 | Tucson Arizona, United States, 85741-2306Madera Family Medical Group- Site Number : 8400029 | Madera California, United States, 93637Integrated Clinical Research- Site Number : 8400056 | Tarzana California, United States, 91356National Institute of Clinical Research - Victorville - Hesperia Road- Site Number : 8400040 | Victorville California, United States, 92395Moore Clinical Research - Brandon- Site Number : 8400065 | Brandon Florida, United States, 33511Invictus Clinical Research Group- Site Number : 8400035 | Coconut Creek Florida, United States, 33073Site Number : 8400031 | Doral Florida, United States, 33122-1088Nona Pediatric Center- Site Number : 8400068 | Orlando Florida, United States, 32829Teena Hughes Pediatrics- Site Number : 8400042 | Tampa Florida, United States, 33613Morehouse School of Medicine - Atlanta- Site Number : 8400037 | Atlanta Georgia, United States, 30310Emory-Children's Center- Site Number : 8400001 | Atlanta Georgia, United States, 30322-1014Agile Clinical Research Trials- Site Number : 8400015 | Atlanta Georgia, United States, 30328Tekton Research, LLC - 4961 Buford Hwy - Georgia - PPDS- Site Number : 8400064 | Chamblee Georgia, United States, 30341Velocity Clinical Research - (Macon - Georgia) - PPDS- Site Number : 8400041 | Macon Georgia, United States, 31210iResearch Savannah - CenExel - PPDS- Site Number : 8400032 | Savannah Georgia, United States, 31405-5701Medical Research Partners - Ammon- Site Number : 8400059 | Ammon Idaho, United States, 83406Clinical Research Prime- Site Number : 8400013 | Idaho Falls Idaho, United States, 83404Leavitt Women's Healthcare- Site Number : 8400033 | Idaho Falls Idaho, United States, 83404Snake River Research- Site Number : 8400046 | Idaho Falls Idaho, United States, 83404Michigan Institute of Research- Site Number : 8400055 | Allen Park Michigan, United States, 48101Vida Clinical Studies - Dearborn Heights- Site Number : 8400072 | Dearborn Heights Michigan, United States, 48127Great Lakes Research Institute- Site Number : 8400060 | Southfield Michigan, United States, 48075Clinical Research Institute - Minneapolis- Site Number : 8400011 | Minneapolis Minnesota, United States, 55402Boeson Research - Great Falls- Site Number : 8400008 | Great Falls Montana, United States, 59405Velocity Clinical Research - Grand Island- Site Number : 8400017 | Grand Island Nebraska, United States, 68803Be Well Clinical Studies - Lincoln- Site Number : 8400058 | Lincoln Nebraska, United States, 68516Velocity Clinical Research (Norfolk - Nebraska) - PPDS- Site Number : 8400038 | Norfolk Nebraska, United States, 68701-2669Quality Clinical Research - Omaha - Regency Circle- Site Number : 8400016 | Omaha Nebraska, United States, 68114Velocity Clinical Research - Omaha- Site Number : 8400054 | Omaha Nebraska, United States, 68134Prime Global Research, Inc.- Site Number : 8400043 | The Bronx New York, United States, 10456-2102Cincinnati Children's Hospital Medical Center- Site Number : 8400063 | Cincinnati Ohio, United States, 45229Senders Pediatrics- Site Number : 8400006 | South Euclid Ohio, United States, 44121Cyn3rgy Research- Site Number : 8400014 | Gresham Oregon, United States, 97030Medical University of South Carolina - Charleston - Jonathan Lucas Street- Site Number : 8400036 | Charleston South Carolina, United States, 29425Palmetto Pediatrics- Site Number : 8400012 | North Charleston South Carolina, United States, 29406Parkside Pediatrics - Simpsonville- Site Number : 8400071 | Simpsonville South Carolina, United States, 29681Clinical Research Associates Inc- Site Number : 8400005 | Nashville Tennessee, United States, 37203-2066Tekton Research, LLC - Beaumont - PPDS- Site Number : 8400061 | Beaumont Texas, United States, 77706-3061South Texas Urgent Care - Del Rio- Site Number : 8400062 | Del Rio Texas, United States, 78840-3927Ventavia Research Group - Fort Worth- Site Number : 8400022 | Fort Worth Texas, United States, 76104Private Practice - Dr. Chinyere N. Awa- Site Number : 8400066 | Houston Texas, United States, 77057DM Clinical Research - CyFair Clinical Research Center- Site Number : 8400044 | Houston Texas, United States, 77065Maximos Ob/Gyn- Site Number : 8400023 | League City Texas, United States, 77573Pediatric Center - Richmond- Site Number : 8400019 | Richmond Texas, United States, 77469Tekton Research - FM78- Site Number : 8400067 | San Antonio Texas, United States, 78244Alliance for Multispecialty Research - Layton - North Robins Drive- Site Number : 8400030 | Layton Utah, United States, 84041Wee Care Pediatrics - Roy- Site Number : 8400002 | Roy Utah, United States, 84067Wee Care Pediatrics - Syracuse- Site Number : 8400004 | Syracuse Utah, United States, 84075Investigational Site Number : 0320007 | Buenos Aires Buenos Aires F.D., Argentina, C1425Investigational Site Number : 0320003 | Río Cuarto Córdoba Province, Argentina, X5800Investigational Site Number : 0320005 | Rosario Santa Fe Province, Argentina, S2013DTCInvestigational Site Number : 0320004 | San Miguel de Tucumán Tucumán Province, Argentina, 4000Investigational Site Number : 0320002 | SAN Miguel de Tucumã¡n Tucumán Province, Argentina, T4000Investigational Site Number : 0320001 | Buenos Aires , Argentina, 1426Investigational Site Number : 0320006 | Buenos Aires , Argentina, 1426Obras Sociais Irmã Dulce - Patamares- Site Number : 0760009 | Salvador Estado de Bahia, Brazil, 41680-020Freire Pesquisa Clínica - Belo Horizonte - Rua Piauí- Site Number : 0760001 | Belo Horizonte Minas Gerais, Brazil, 30150-320Hospital de Clinicas de Porto Alegre- Site Number : 0760005 | Porto Alegre Rio Grande do Sul, Brazil, 90035-903Hospital Ernesto Dornelles- Site Number : 0760007 | Porto Alegre Rio Grande do Sul, Brazil, 90160-093Hospital Das Clinicas da Faculdade de Medicina de Ribeirão Preto - USP - PPDS- Site Number : 0760010 | Ribeirão Preto São Paulo, Brazil, 14015-010Fundação Faculdade Regional de Medicina de São José do Rio Preto- Site Number : 0760006 | São José do Rio Preto São Paulo, Brazil, 15090-000Escola Paulista De Medicina- Site Number : 0760002 | Vila Clementino São Paulo, Brazil, 04023-062Centro Paulista de Investigaçăo Clínica - CEPIC- Site Number : 0760004 | São Paulo , Brazil, 04265-000Investigational Site Number : 1520004 | Santiago Reg Metropolitana de Santiago, Chile, 8331143Investigational Site Number : 1520001 | Santiago Reg Metropolitana de Santiago, Chile, 8380418Investigational Site Number : 1520005 | Port Montt , Chile, 5480000Investigational Site Number : 1560009 | Jiangsu , China, 221699Investigational Site Number : 1700004 | Acacías , Colombia, 507001Investigational Site Number : 1700002 | Chía , Colombia, 250001Investigational Site Number : 1700003 | Girardot , Colombia, 252431Investigational Site Number : 2460003 | Espoo , Finland, 02230Investigational Site Number : 2460005 | Helsinki , Finland, 00100Investigational Site Number : 2460008 | Jarvenpaa , Finland, 04400Investigational Site Number : 2460004 | Kokkola , Finland, 67100Investigational Site Number : 2460002 | Oulu , Finland, 90220Investigational Site Number : 2460006 | Seinäjoki , Finland, 60100Investigational Site Number : 2460009 | Tampere , Finland, 33100Investigational Site Number : 2460001 | Turku , Finland, 20520Investigational Site Number : 3920008 | Lizuka-shi Fukuoka, Japan, 820-0040Investigational Site Number : 3920011 | Sapporo Hokkaido, Japan, 063-0841Investigational Site Number : 3920007 | Kawagoe Saitama, Japan, 350-0001Investigational Site Number : 3920010 | Shizuoka-Shi Aoi-Ku Shizuoka, Japan, 420-0005Investigational Site Number : 3920006 | Edogawa-Ku Tokyo, Japan, 133-0056Investigational Site Number : 3920001 | Fukui , Japan, 910-0833Investigational Site Number : 3920002 | Fukui-shi , Japan, 910-0808Investigational Site Number : 3920004 | Fukuoka , Japan, 813-0036Investigational Site Number : 3920003 | Kagoshima , Japan, 890-0034Investigational Site Number : 3920005 | Kasuga-Shi , Japan, 816-0801Investigational Site Number : 3920009 | Osaka , Japan, 556-0005Investigational Site Number : 4040007 | Butere , Kenya, 50101Investigational Site Number : 4040002 | Kisumu , Kenya, 40100Investigational Site Number : 4040003 | Kisumu , Kenya, 40100Investigational Site Number : 4040001 | Nairobi , Kenya, 00202Investigational Site Number : 4040006 | Nairobi , Kenya, KENYAInvestigational Site Number : 4840008 | Monterrey Nuevo León, Mexico, 64060Investigational Site Number : 4840007 | Mexico City , Mexico, 14090Investigational Site Number : 4840004 | Veracruz , Mexico, 91900Investigational Site Number : 5240003 | Dhulikhel N.p Bagmati, Nepal, 45210Investigational Site Number : 5240001 | Kathmandu Bagmati, Nepal, 44600Investigational Site Number : 5240002 | Nepalgunj Bheri, Nepal, 21900Clinical Research Investigator Group- Site Number : 6300001 | Bayamón , Puerto Rico, 00961-7041Clinical Research Puerto Rico (CRPR), Inc. - Guayama- Site Number : 6300005 | Guayama , Puerto Rico, 00784Caribbean Medical Research Center- Site Number : 6300003 | San Juan , Puerto Rico, 00918Hospital Pediatrico Universitario- Site Number : 6300002 | San Juan , Puerto Rico, 00923Investigational Site Number : 7100007 | Brits , South Africa, 0250Investigational Site Number : 7100008 | City of Cape Town , South Africa, 7500Investigational Site Number : 7100001 | East London , South Africa, 5241Investigational Site Number : 7100005 | Johannesburg , South Africa, 2001Investigational Site Number : 7100004 | Johannesburg , South Africa, 2013Investigational Site Number : 7100003 | Johannesburg , South Africa, 2193Investigational Site Number : 7100006 | Paarl , South Africa, 7626Investigational Site Number : 7100002 | Pretoria , South Africa, 0122Investigational Site Number : 7100009 | Soshanguve , South Africa, 0152Investigational Site Number : 7240004 | Santiago de Compostela A Coruña [La Coruña], Spain, 15706Investigational Site Number : 7240001 | Barcelona Catalunya [Cataluña], Spain, 08023Investigational Site Number : 7240003 | Móstoles Madrid, Spain, 28938Investigational Site Number : 7240005 | Pamplona Navarre, Spain, 31008Investigational Site Number : 7240002 | Seville Sevilla, Spain, 41013Investigational Site Number : 7640002 | Bangkok , Thailand, 10400Investigational Site Number : 7640005 | Bangkok , Thailand, 10400Investigational Site Number : 7640004 | Bangkok , Thailand, 10700Investigational Site Number : 7640001 | Chiang Mai , Thailand, 50180Investigational Site Number : 7640006 | Hat Yai , Thailand, 90110Investigational Site Number : 7640003 | Khon Kaen , Thailand, 40002Investigational Site Number : 8260003 | Hayle Cornwall, United Kingdom, TR27 5DTInvestigational Site Number : 8260005 | Exeter Devon, United Kingdom, EX2 5DWInvestigational Site Number : 8260007 | Southampton Hampshire, United Kingdom, SO16 6YDInvestigational Site Number : 8260004 | Bristol , United Kingdom, BS1 3NU