{
  "api_version": "1",
  "request": {
    "url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=Quadrivalent+Influenza+Vaccine+High+Dose",
    "query": {
      "intervention": "Quadrivalent Influenza Vaccine High Dose"
    },
    "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=Quadrivalent+Influenza+Vaccine+High+Dose&page=2&page_size=10",
    "previous_page_url": null
  },
  "source": "remote",
  "last_synced_at": "2026-10-02T19:50:09.766Z",
  "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": "NCT06361875",
      "title": "A Study to Investigate the Safety and Immunogenicity of the Quadrivalent Influenza mRNA Vaccines in Adults Aged 18 Years and Above",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Influenza Immunization",
        "Healthy Volunteers"
      ],
      "interventions": [
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5421",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5424",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5429",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza Standard Dose Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza High-Dose Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Recombinant Influenza 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": 908,
      "start_date": "2024-04-01",
      "completion_date": "2025-06-09",
      "has_results": true,
      "last_update_posted_date": "2026-08-04",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 11,
      "location_summary": "San Diego, California • Hialeah, Florida • Hollywood, Florida + 8 more",
      "locations": [
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Hialeah",
          "state": "Florida"
        },
        {
          "city": "Hollywood",
          "state": "Florida"
        },
        {
          "city": "Indianapolis",
          "state": "Indiana"
        },
        {
          "city": "Lexington",
          "state": "Kentucky"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06361875"
    },
    {
      "nct_id": "NCT06060457",
      "title": "A Study to Evaluate the Safety and Immune Response of mRNA-1345, a Vaccine Targeting Respiratory Syncytial Virus (RSV), When Co-administered With a Fluzone HD, in Adults ≥65 Years of Age",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Respiratory Syncytial Virus"
      ],
      "interventions": [
        {
          "name": "Placebo",
          "type": "BIOLOGICAL"
        },
        {
          "name": "mRNA-1345",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluzone HD",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "ModernaTX, Inc.",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "65 Years and older"
      },
      "enrollment_count": 1900,
      "start_date": "2023-09-25",
      "completion_date": "2024-06-07",
      "has_results": true,
      "last_update_posted_date": "2025-07-30",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 34,
      "location_summary": "Scottsdale, Arizona • Dublin, California • Riverside, California + 29 more",
      "locations": [
        {
          "city": "Scottsdale",
          "state": "Arizona"
        },
        {
          "city": "Scottsdale",
          "state": "Arizona"
        },
        {
          "city": "Dublin",
          "state": "California"
        },
        {
          "city": "Riverside",
          "state": "California"
        },
        {
          "city": "Rolling Hills Estates",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06060457"
    },
    {
      "nct_id": "NCT04551677",
      "title": "Annual Study for Collection of Serum Samples in Children and Older Adults Receiving the 2020-2021 Formulations of Fluzone Quadrivalent Vaccine and Fluzone High-Dose Quadrivalent Vaccine, Respectively",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Influenza Immunization",
        "Healthy Volunteers"
      ],
      "interventions": [
        {
          "name": "Fluzone Quadrivalent vaccine, No Preservative (0.5-mL dose), 2020-2021 formulation",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluzone High-Dose Quadrivalent vaccine (0.7-mL dose), 2020-2021 formulation",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "6 Months",
        "maximum_age": "84 Years",
        "sex": "ALL",
        "summary": "6 Months to 84 Years"
      },
      "enrollment_count": 90,
      "start_date": "2020-09-16",
      "completion_date": "2020-12-18",
      "has_results": true,
      "last_update_posted_date": "2025-09-12",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 2,
      "location_summary": "Bardstown, Kentucky • Salt Lake City, Utah",
      "locations": [
        {
          "city": "Bardstown",
          "state": "Kentucky"
        },
        {
          "city": "Salt Lake City",
          "state": "Utah"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04551677"
    },
    {
      "nct_id": "NCT02307851",
      "title": "Quadrivalent Influenza VLP Vaccine Dose Ranging Study in Young Adults",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Quadrivalent VLP Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Comparator TIV",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Novavax",
      "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": 400,
      "start_date": "2014-11",
      "completion_date": "2015-06",
      "has_results": false,
      "last_update_posted_date": "2016-09-23",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 5,
      "location_summary": "Anaheim, California • Miami, Florida • Lenexa, Kansas + 2 more",
      "locations": [
        {
          "city": "Anaheim",
          "state": "California"
        },
        {
          "city": "Miami",
          "state": "Florida"
        },
        {
          "city": "Lenexa",
          "state": "Kansas"
        },
        {
          "city": "Omaha",
          "state": "Nebraska"
        },
        {
          "city": "San Antonio",
          "state": "Texas"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT02307851"
    },
    {
      "nct_id": "NCT06744205",
      "title": "A Study on the Safety and Immunogenicity of Hexavalent Influenza mRNA Vaccine in Adult Participants 50 Years of Age and Older",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Influenza",
        "Healthy Volunteers"
      ],
      "interventions": [
        {
          "name": "Trivalent (TIV) messenger ribonucleic acid (mRNA) hemagglutinin (HA) Vaccine 1",
          "type": "BIOLOGICAL"
        },
        {
          "name": "TIV mRNA-neuraminidase (NA)",
          "type": "BIOLOGICAL"
        },
        {
          "name": "TIV mRNA-HA Vaccine 2",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza Standard Dose Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza Vaccine High Dose",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "50 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "50 Years and older"
      },
      "enrollment_count": 1162,
      "start_date": "2025-01-06",
      "completion_date": "2026-05-22",
      "has_results": false,
      "last_update_posted_date": "2026-06-09",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 21,
      "location_summary": "Birmingham, Alabama • Mobile, Alabama • Tempe, Arizona + 18 more",
      "locations": [
        {
          "city": "Birmingham",
          "state": "Alabama"
        },
        {
          "city": "Mobile",
          "state": "Alabama"
        },
        {
          "city": "Tempe",
          "state": "Arizona"
        },
        {
          "city": "Coral Gables",
          "state": "Florida"
        },
        {
          "city": "DeLand",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06744205"
    },
    {
      "nct_id": "NCT05291676",
      "title": "Systems Investigation of Vaccine Responses in Aging and Frailty",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Fluzone",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluad",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Yale University",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "21 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "21 Years and older"
      },
      "enrollment_count": 96,
      "start_date": "2023-11-06",
      "completion_date": "2027-04",
      "has_results": false,
      "last_update_posted_date": "2025-06-12",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 1,
      "location_summary": "New Haven, Connecticut",
      "locations": [
        {
          "city": "New Haven",
          "state": "Connecticut"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05291676"
    },
    {
      "nct_id": "NCT05945485",
      "title": "A Study to Evaluate the Safety and Immunogenicity of Two Doses of DCVC H1 HA mRNA-LNP in Healthy Adults",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "DCVC H1 HA mRNA vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Recombinant Seasonal Influenza Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Sodium Chloride, 0.9%",
          "type": "OTHER"
        }
      ],
      "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": "2023-10-16",
      "completion_date": "2026-05-21",
      "has_results": false,
      "last_update_posted_date": "2026-06-22",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 1,
      "location_summary": "Iowa City, Iowa",
      "locations": [
        {
          "city": "Iowa City",
          "state": "Iowa"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05945485"
    },
    {
      "nct_id": "NCT04487041",
      "title": "Tfh Dysfunction in HIV and Aging",
      "overall_status": "ACTIVE_NOT_RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Human Influenza"
      ],
      "interventions": [
        {
          "name": "Standard dose influenza vaccination",
          "type": "BIOLOGICAL"
        },
        {
          "name": "High dose influenza vaccination",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "University of Miami",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 400,
      "start_date": "2020-10-30",
      "completion_date": "2027-12-30",
      "has_results": false,
      "last_update_posted_date": "2026-07-17",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 1,
      "location_summary": "Miami, Florida",
      "locations": [
        {
          "city": "Miami",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04487041"
    },
    {
      "nct_id": "NCT02787044",
      "title": "INfluenza Vaccine to Effectively Stop Cardio Thoracic Events and Decompensated Heart Failure",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Heart Failure",
        "Myocardial Infarction"
      ],
      "interventions": [
        {
          "name": "High Dose Trivalent Influenza Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Standard Dose Quadrivalent Influenza Vaccine",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Brigham and Women's Hospital",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 5388,
      "start_date": "2016-08-01",
      "completion_date": "2020-05-31",
      "has_results": true,
      "last_update_posted_date": "2022-01-21",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 127,
      "location_summary": "Birmingham, Alabama • Huntsville, Alabama • Anchorage, Alaska + 93 more",
      "locations": [
        {
          "city": "Birmingham",
          "state": "Alabama"
        },
        {
          "city": "Birmingham",
          "state": "Alabama"
        },
        {
          "city": "Huntsville",
          "state": "Alabama"
        },
        {
          "city": "Anchorage",
          "state": "Alaska"
        },
        {
          "city": "Tucson",
          "state": "Arizona"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT02787044"
    },
    {
      "nct_id": "NCT03658629",
      "title": "Phase 2 Dose and Formulation Confirmation of Quad-NIV in Older Adults",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Influenza, Human"
      ],
      "interventions": [
        {
          "name": "NanoFlu (Quad-NIV)",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Matrix-M Adjuvant",
          "type": "OTHER"
        },
        {
          "name": "Placebo",
          "type": "OTHER"
        },
        {
          "name": "Fluzone HD",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Flublok Quadrivalent",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Influenza Vaccine",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL",
        "OTHER"
      ],
      "sponsor": "Novavax",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "65 Years and older"
      },
      "enrollment_count": 1375,
      "start_date": "2018-09-24",
      "completion_date": "2019-04-26",
      "has_results": true,
      "last_update_posted_date": "2022-11-04",
      "last_synced_at": "2026-10-02T19:50:09.766Z",
      "location_count": 14,
      "location_summary": "Hollywood, Florida • Savannah, Georgia • Stockbridge, Georgia + 11 more",
      "locations": [
        {
          "city": "Hollywood",
          "state": "Florida"
        },
        {
          "city": "Savannah",
          "state": "Georgia"
        },
        {
          "city": "Stockbridge",
          "state": "Georgia"
        },
        {
          "city": "Rockville",
          "state": "Maryland"
        },
        {
          "city": "Norfolk",
          "state": "Nebraska"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03658629"
    }
  ]
}