{
  "api_version": "1",
  "request": {
    "url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=High-dose+quadrivalent+influenza+virus+vaccine",
    "query": {
      "intervention": "High-dose quadrivalent influenza virus vaccine"
    },
    "page_size": 10
  },
  "pagination": {
    "page": 1,
    "page_size": 10,
    "total_count": 56,
    "total_pages": 6,
    "next_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=High-dose+quadrivalent+influenza+virus+vaccine&page=2&page_size=10",
    "previous_page_url": null
  },
  "source": "remote",
  "last_synced_at": "2026-10-07T19:07:06.812Z",
  "attribution": "Data derived from public ClinicalTrials.gov records. The official record at https://clinicaltrials.gov/ remains the source of truth for current availability, contacts, and full study details.",
  "notes": [
    "This endpoint exposes only public summary fields — no participant contact emails, phone numbers, or scraped investigator contact details.",
    "For contact information and full protocol detail, follow each trial's `official_url` to the ClinicalTrials.gov record.",
    "This API is a navigational aid. It does not provide medical advice, eligibility determinations, or compensation guarantees."
  ],
  "trials": [
    {
      "nct_id": "NCT05755620",
      "title": "A Study to Evaluate the Safety and Immunogenicity of a Single Dose of H1ssF-3928 mRNA-LNP in Healthy Adults",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Influenza Virus Quadrivalent Inactivated Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Sodium Chloride, 0.9%",
          "type": "OTHER"
        },
        {
          "name": "VRC-FLUNPF099-00-VP (H1ssF_3928)",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL",
        "OTHER"
      ],
      "sponsor": "National Institute of Allergy and Infectious Diseases (NIAID)",
      "sponsor_class": "NIH",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "49 Years",
        "sex": "ALL",
        "summary": "18 Years to 49 Years"
      },
      "enrollment_count": 50,
      "start_date": "2023-04-05",
      "completion_date": "2025-10-03",
      "has_results": false,
      "last_update_posted_date": "2026-06-18",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 1,
      "location_summary": "Durham, North Carolina",
      "locations": [
        {
          "city": "Durham",
          "state": "North Carolina"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05755620"
    },
    {
      "nct_id": "NCT05071313",
      "title": "A Study of an Ad26.RSV.preF-based Vaccine and High-dose Seasonal Influenza Vaccine, With and Without Coadministration, in Adults Aged 65 Years and Older",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Influenza, Human Prevention",
        "Respiratory Syncytial Viruses Prevention"
      ],
      "interventions": [
        {
          "name": "Ad26.RSV.preF-based vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent High-dose Influenza Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Placebo",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Janssen Vaccines & Prevention B.V.",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "65 Years and older"
      },
      "enrollment_count": 777,
      "start_date": "2021-10-04",
      "completion_date": "2022-10-11",
      "has_results": true,
      "last_update_posted_date": "2025-05-25",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 19,
      "location_summary": "Long Beach, California • Hollywood, Florida • Port Orange, Florida + 14 more",
      "locations": [
        {
          "city": "Long Beach",
          "state": "California"
        },
        {
          "city": "Hollywood",
          "state": "Florida"
        },
        {
          "city": "Port Orange",
          "state": "Florida"
        },
        {
          "city": "The Villages",
          "state": "Florida"
        },
        {
          "city": "Chicago",
          "state": "Illinois"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05071313"
    },
    {
      "nct_id": "NCT05007041",
      "title": "Simultaneous RZV and aIIV4 Vaccination",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Pain",
        "Quality of Life",
        "Injection Site Reaction",
        "Adverse Drug Event"
      ],
      "interventions": [
        {
          "name": "FLUAD® Quadrivalent",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluzone® High-Dose Quadrivalent",
          "type": "BIOLOGICAL"
        },
        {
          "name": "SHINGRIX®",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Duke University",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "65 Years and older"
      },
      "enrollment_count": 267,
      "start_date": "2021-09-21",
      "completion_date": "2023-06-08",
      "has_results": true,
      "last_update_posted_date": "2024-07-11",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 2,
      "location_summary": "Baltimore, Maryland • Durham, North Carolina",
      "locations": [
        {
          "city": "Baltimore",
          "state": "Maryland"
        },
        {
          "city": "Durham",
          "state": "North Carolina"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05007041"
    },
    {
      "nct_id": "NCT01991587",
      "title": "Safety, Tolerability and Immunogenicity of a Plant-made Seasonal Quadrivalent VLP Influenza Vaccine in Adults",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Virus Diseases",
        "RNA Virus Infections",
        "Respiratory Tract Diseases",
        "Respiratory Tract Infections"
      ],
      "interventions": [
        {
          "name": "Low dose of quadrivalent VLP vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Medium dose of quadrivalent VLP vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "High dose of quadrivalent VLP vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Placebo",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Medicago",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "49 Years",
        "sex": "ALL",
        "summary": "18 Years to 49 Years"
      },
      "enrollment_count": 120,
      "start_date": "2013-10-08",
      "completion_date": "2014-06-30",
      "has_results": false,
      "last_update_posted_date": "2020-06-11",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 1,
      "location_summary": "Miami, Florida",
      "locations": [
        {
          "city": "Miami",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT01991587"
    },
    {
      "nct_id": "NCT02908269",
      "title": "Safety and Immunogenicity of Fluzone® Quadrivalent and Fluzone® High-Dose, Influenza Vaccines, 2016-2017 Formulations",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Fluzone Quadrivalent vaccine, 2016-2017 formulation, No Preservative",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluzone High-Dose, vaccine, 2016-2017 formulation",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "3 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "3 Years and older"
      },
      "enrollment_count": 180,
      "start_date": "2016-09-15",
      "completion_date": "2016-12-09",
      "has_results": true,
      "last_update_posted_date": "2022-03-29",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 2,
      "location_summary": "Bardstown, Kentucky • Metairie, Louisiana",
      "locations": [
        {
          "city": "Bardstown",
          "state": "Kentucky"
        },
        {
          "city": "Metairie",
          "state": "Louisiana"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT02908269"
    },
    {
      "nct_id": "NCT05663463",
      "title": "Seasonal Influenza Vaccine High Dose Boosting in Solid Organ Transplant Recipients",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "NA"
      ],
      "conditions": [
        "Solid Organ Transplant"
      ],
      "interventions": [
        {
          "name": "Fluzone High-Dose - 2 doses",
          "type": "DRUG"
        },
        {
          "name": "Fluzone High-Dose - 1 dose of HD",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "University of Minnesota",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 74,
      "start_date": "2023-09-11",
      "completion_date": "2025-06-16",
      "has_results": false,
      "last_update_posted_date": "2025-07-15",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 1,
      "location_summary": "Minneapolis, Minnesota",
      "locations": [
        {
          "city": "Minneapolis",
          "state": "Minnesota"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05663463"
    },
    {
      "nct_id": "NCT02563093",
      "title": "Study of Fluzone® Quadrivalent, Fluzone® Intradermal Quadrivalent, and Fluzone® High-Dose, Influenza Vaccines in Adults",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Fluzone Quadrivalent vaccine, 2015-2016 formulation, No Preservative",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluzone Intradermal Quadrivalent vaccine, 2015-2016 formulation",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluzone High-Dose vaccine, 2015-2016 formulation",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 208,
      "start_date": "2015-09",
      "completion_date": "2016-07",
      "has_results": true,
      "last_update_posted_date": "2016-12-12",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 4,
      "location_summary": "Santa Rosa, California • Council Bluffs, Iowa • Metairie, Louisiana + 1 more",
      "locations": [
        {
          "city": "Santa Rosa",
          "state": "California"
        },
        {
          "city": "Council Bluffs",
          "state": "Iowa"
        },
        {
          "city": "Metairie",
          "state": "Louisiana"
        },
        {
          "city": "Cincinnati",
          "state": "Ohio"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT02563093"
    },
    {
      "nct_id": "NCT04544267",
      "title": "Study on a High-Dose Quadrivalent Influenza Vaccine Compared With Standard-Dose Quadrivalent Influenza Vaccine in Children 6 Months Through 35 Months of Age",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Quadrivalent influenza vaccine, high-dose",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent influenza vaccine, standard dose",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "6 Months",
        "maximum_age": "35 Months",
        "sex": "ALL",
        "summary": "6 Months to 35 Months"
      },
      "enrollment_count": 100,
      "start_date": "2020-09-15",
      "completion_date": "2021-06-02",
      "has_results": true,
      "last_update_posted_date": "2025-12-24",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 10,
      "location_summary": "San Diego, California • Miami, Florida • Atlanta, Georgia + 6 more",
      "locations": [
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Miami",
          "state": "Florida"
        },
        {
          "city": "Atlanta",
          "state": "Georgia"
        },
        {
          "city": "El Dorado",
          "state": "Kansas"
        },
        {
          "city": "Bardstown",
          "state": "Kentucky"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04544267"
    },
    {
      "nct_id": "NCT03282240",
      "title": "Safety and Immunogenicity of High-Dose Quadrivalent Influenza Vaccine in Participants ≥65 Years in the US",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "QIV-HD",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Licensed TIV-HD1",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Investigational TIV-HD2",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "65 Years and older"
      },
      "enrollment_count": 2670,
      "start_date": "2017-09-08",
      "completion_date": "2018-04-19",
      "has_results": true,
      "last_update_posted_date": "2022-04-07",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 36,
      "location_summary": "Anaheim, California • Redding, California • San Diego, California + 29 more",
      "locations": [
        {
          "city": "Anaheim",
          "state": "California"
        },
        {
          "city": "Redding",
          "state": "California"
        },
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Colorado Springs",
          "state": "Colorado"
        },
        {
          "city": "Milford",
          "state": "Connecticut"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03282240"
    },
    {
      "nct_id": "NCT05553301",
      "title": "Safety and Immunogenicity of Quadrivalent Influenza mRNA Vaccine MRT5407 in Adult Participants18 Years of Age and Older",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Influenza Immunization"
      ],
      "interventions": [
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5407",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Recombinant Influenza Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza Standard Dose Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza High-Dose Vaccine",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 560,
      "start_date": "2022-10-03",
      "completion_date": "2024-01-19",
      "has_results": false,
      "last_update_posted_date": "2025-01-24",
      "last_synced_at": "2026-10-07T19:07:06.812Z",
      "location_count": 23,
      "location_summary": "Rolling Hills Estates, California • San Diego, California • DeLand, Florida + 16 more",
      "locations": [
        {
          "city": "Rolling Hills Estates",
          "state": "California"
        },
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "DeLand",
          "state": "Florida"
        },
        {
          "city": "Gainesville",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05553301"
    }
  ]
}