Medical Information Only. Consult your healthcare provider before considering clinical trial enrollment.

ClinicalTrials.gov 27 recruiting now official registry

Influenza clinical trials

Every US clinical trial registered for Influenza — phase mix, recruiting status, and the sponsors running them, straight from the NIH ClinicalTrials.gov registry.

157 US clinical trials · 27 currently recruiting

The research picture

Influenza has 157 registered US clinical trials, 27 of them open to new participants right now — about 17% of the total.

27
recruiting participants now
17%
of trials open to enrollment
42
in Phase 3–4 (later-stage)
36
top sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Counts reflect the public ClinicalTrials.gov registry as last mirrored by PlainTrial. Status and phase are reported by each study's sponsor. This is reference information, not medical advice.

Active & Recent Trials

RECRUITING 960,000 participants

Fluad vs. Fluzone High-Dose Vaccine Effectiveness Among Adults ≥65 Years

Kaiser Permanente

NCT06029933

RECRUITING 400,000 participants

Clinical Outcomes and Pharmacotherapy Effectiveness in the VA Health Care System (COPE-VA)

VA Office of Research and Development

NCT06160128

RECRUITING 100,000 participants

The DETECT(Digital Engagement & Tracking for Early Control, & Treatment) Study

Scripps Translational Science Institute

NCT04336020

RECRUITING NA 22,000 participants

The INFLUENTIAL Trial- Evaluation of National Inpatient Influenza Vaccination Program

University of Colorado, Denver

NCT05832307

RECRUITING 20,000 participants

Respiratory Virus Sampling and Repository

National Institute of Allergy and Infectious Diseases (NIAID)

NCT05266222

RECRUITING 10,000 participants

Influenza & COVID-19 Obstetric and Perinatal Epidemiology Study in India

Boston University

NCT06168019

RECRUITING 5,000 participants

Screening for LID Clinical Studies Unit Healthy Volunteer Protocols

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01386424

RECRUITING NA 1,400 participants

Dime La VerDAD: Verify, Debunk, and Disseminate

University of Chicago

NCT06417762

RECRUITING NA 1,025 participants

Influenza Immunization in Adults Over Age 75

Johns Hopkins University

NCT02200276

RECRUITING 1,000 participants

Observational Digital Biomarker Discovery in Respiratory Virus Challenge Studies

National Institute of Allergy and Infectious Diseases (NIAID)

NCT04772170

RECRUITING Phase 3 750 participants

A Surveillance Study of Susceptibility to Baloxavir Marboxil in Pediatric Participants With Influenza and Transmission of Influenza to Household Contacts

Hoffmann-La Roche

NCT06094010

RECRUITING Phase 2 312 participants

High vs.Standard Dose Influenza Vaccine in Pediatric Solid Organ Transplant (SOT) Recipients

National Institute of Allergy and Infectious Diseases (NIAID)

NCT05947071

RECRUITING NA 300 participants

Immune Defense Protein Impact On Respiratory Immune Outcomes

Quantec

NCT07431840

RECRUITING 300 participants

Dissecting Human Immune Responses to Infection With Influenza or SARS-CoV-2

Washington University School of Medicine

NCT06848309

RECRUITING Phase 2 270 participants

High vs. Standard Dose Influenza Vaccine in Lung Allograft Recipients

Vanderbilt University Medical Center

NCT05215327

RECRUITING Phase 1 180 participants

pH1N1 Blinded Challenge Study

National Institute of Allergy and Infectious Diseases (NIAID)

NCT07110532

RECRUITING 150 participants

Natural History of Systemic and Nasal Mucosal Immunity to Influenza and SARS-CoV-2 in Adults After Vaccination

National Institute of Allergy and Infectious Diseases (NIAID)

NCT04794829

RECRUITING Phase 2 96 participants

Systems Investigation of Vaccine Responses in Aging and Frailty

Yale University

NCT05291676

RECRUITING Phase 4 90 participants

Bone Marrow and Peripheral Blood Immune Responses Study

Emory University

NCT05616546

RECRUITING Phase 1 80 participants

Influenza Human Challenge Model

Emory University

NCT05332899

RECRUITING Phase 1 78 participants

First-in-Human Study of VNT-101: Safety, Tolerability, and Pharmacokinetics

National Institute of Allergy and Infectious Diseases (NIAID)

NCT07169318

RECRUITING Phase 2 60 participants

High vs. Standard Dose Influenza Vaccines in Lung Transplant (Repeater)

Vanderbilt University Medical Center

NCT07192458

RECRUITING Phase 2 60 participants

Baloxavir and Oseltamivir for the Treatment of Severe Influenza Infection in Immunocompromised Patients

M.D. Anderson Cancer Center

NCT04712539

RECRUITING Phase 4 54 participants

Comparative Immunogenicity of Respiratory Virus Vaccines (CIRV2) Study

Henry M. Jackson Foundation for the Advancement of Military Medicine

NCT07287137

RECRUITING Phase 4 50 participants

B Cell and Antibody Response to Seasonal Influenza Vaccines in Younger and Older Adults

University of Alabama at Birmingham

NCT04101838

RECRUITING Phase 1 50 participants

A/Texas Flu Challenge

Emory University

NCT06753474

RECRUITING NA 30 participants

H5N1 Milk Detection Study

Emory University

NCT06850298

ACTIVE NOT RECRUITING NA 3,668,428 participants

Kaiser Permanente VACCination Improvement With Nudge-based CardiovAscular Targeted Engagement

Kaiser Permanente

NCT06571747

ACTIVE NOT RECRUITING NA 100,000 participants

Kaiser Colorado Flu Nudge

Kaiser Permanente

NCT07372950

ACTIVE NOT RECRUITING Phase 3 7,500 participants

A Study to Evaluate the Safety and Efficacy of CD388 for Prevention of Influenza

Cidara Therapeutics

NCT07159763

ACTIVE NOT RECRUITING 1,500 participants

Influenza IMPRINT Cohort: Defining the Impact of Initial Influenza Exposure on Immunity in Infants

Children's Hospital Medical Center, Cincinnati

NCT05436184

ACTIVE NOT RECRUITING Phase 1 1,162 participants

A Study on the Safety and Immunogenicity of Hexavalent Influenza mRNA Vaccine in Adult Participants 50 Years of Age and Older

Sanofi Pasteur, a Sanofi Company

NCT06744205

ACTIVE NOT RECRUITING 1,000 participants

Longitudinal At Home Smell Testing to Detect Infection by SARS-CoV-2

Massachusetts General Hospital

NCT05040659

ACTIVE NOT RECRUITING 999 participants

A Study to Look at the Health Outcomes of Patients With COVID-19 and Influenza

Pfizer

NCT05160636

ACTIVE NOT RECRUITING Phase 2 396 participants

High vs. Standard Dose Influenza Vaccine in Adult SOT Recipients

Vanderbilt University Medical Center

NCT04613206

ACTIVE NOT RECRUITING 300 participants

SARS-CoV-2/COVID-19 Study of Next Generation Non-Invasive Passive Detection Technologies

The Geneva Foundation

NCT05765396

ACTIVE NOT RECRUITING 74 participants

Association Between Gut Microbiome and Dietary Determinants and Vaccine Response

M.D. Anderson Cancer Center

NCT05239403

ACTIVE NOT RECRUITING Phase 1 50 participants

A Study to Evaluate the Safety and Immunogenicity of Two Doses of DCVC H1 HA mRNA-LNP in Healthy Adults

National Institute of Allergy and Infectious Diseases (NIAID)

NCT05945485

ACTIVE NOT RECRUITING NA 31 participants

Impact of High Dietary Fiber on Microbiome and Vaccine Responses

M.D. Anderson Cancer Center

NCT05565586

ACTIVE NOT RECRUITING NA 26 participants

Exercise and COVID-19 Viral T-cell Immunity

University of Arizona

NCT05019456

ACTIVE NOT RECRUITING Phase 1 12 participants

Pilot Influenza Challenge Study

Daniel Hoft, MD, PhD

NCT07063849

COMPLETED NA 228,000 participants

Mail Outreach To Increase Vaccination Acceptance Through Engagement

Brigham and Women's Hospital

NCT02243774

COMPLETED 96,175 participants

Surveillance Study to Assess the Safety of Flublok Quadrivalent (Influenza Vaccine) in Pregnant Women and Their Offspring

Sanofi Pasteur, a Sanofi Company

NCT04460781

COMPLETED NA 22,233 participants

Patient Portal Flu Vaccine Reminders (RCT 6)

University of California, Los Angeles

NCT06062264

COMPLETED Phase 3 11,404 participants

Efficacy Study of Two Influenza Vaccines and Placebo in Healthy Adult Subjects

Novartis Vaccines

NCT00630331

COMPLETED Phase 3 10,160 participants

Efficacy, Safety, and Immunogenicity of a Plant-Derived Quadrivalent Virus-Like Particles (VLPs) Influenza Vaccine in Adults

Medicago

NCT03301051

COMPLETED 6,234 participants

Project IMPACT Immunizations (IMProving America's Communities Together) Scaled Demonstration

American Pharmacists Association Foundation

NCT03372967

COMPLETED Phase 2 5,071 participants

Study of CD388 for the Prevention of Influenza in Subjects Not at Risk for Influenza Complications

Cidara Therapeutics

NCT06609460

COMPLETED Phase 3 4,561 participants

Immunogenicity & Safety of GSK's Influenza Vaccine 1557484A Given to Adults Aged ≥18 Years

GlaxoSmithKline

NCT00616928

COMPLETED NA 4,455 participants

Study to Evaluate Impact of School-based Influenza Vaccination on School Populations

Children's Hospital Los Angeles

NCT00844051

COMPLETED Phase 3 4,363 participants

Study of Quadrivalent Influenza Vaccine Among Children

Sanofi Pasteur, a Sanofi Company

NCT01240746

COMPLETED Phase 3 4,048 participants

Safety, Immunogenicity, and Relative Efficacy of H1N1 Vaccines in Adults Aged 18 Years and Older

GlaxoSmithKline

NCT00979602

COMPLETED NA 4,026 participants

Adult Influenza Vaccination Text Message Reminders With Electronic Health Record Alerts

Columbia University

NCT02284594

COMPLETED Phase 4 3,000 participants

REDucing Influenza Among University Students, University of California at Berkeley

Centers for Disease Control and Prevention

NCT00448773

COMPLETED Phase 1 2,650 participants

A Study to Learn About How the Flu and COVID-19 Vaccines Act in Healthy People

BioNTech SE

NCT06821061

COMPLETED Phase 3 2,640 participants

Comparison of the Safety of Flublok® Versus Licensed IIV in Healthy, Medically Stable Adults ≥ 50 Years of Age

Protein Sciences Corporation

NCT01825200

COMPLETED Phase 1 1,758 participants

A Study of mRNA-based Influenza and SARS-CoV-2 (COVID-19) Multi-component Vaccines in Healthy Adults

ModernaTX

NCT05827926

COMPLETED NA 1,400 participants

A Study of Exclusion Criteria in a University Population

University of Michigan

NCT01472536

COMPLETED Phase 2 1,357 participants

Safety and Immunogenicity of A/H1N1-SOIV (Swine Flu) Vaccine With and Without Adjuvant in Children (3 to < 9 Years)

Novartis Vaccines

NCT00972816

COMPLETED Phase 3 1,350 participants

Safety and Immunogenicity of Flublok Quadrivalent vs IIV4 in Adults 18-49 Years of Age

Protein Sciences Corporation

NCT02290509

COMPLETED Phase 2 1,343 participants

Safety and Immunogenicity of H1N1 Vaccines in Adults Aged 18 Years and Older

GlaxoSmithKline

NCT00985088

COMPLETED Phase 3 1,180 participants

Study to Evaluate Immunogenicity and Safety of a High-Dose Influenza Vaccine in Adults 50 Through 64 Years of Age

Sanofi Pasteur, a Sanofi Company

NCT06641180

COMPLETED Phase 2 881 participants

Comparing the Efficacy, Safety, and Tolerability of Combination Antivirals (Amantadine, Ribavirin, Oseltamivir) Versus Oseltamivir for the Treatment of Influenza in Adults at Risk for Complications

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01227967

COMPLETED Phase 2 805 participants

Sanofi H1N1 + TIV - Adults and Elderly

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00943878

COMPLETED Phase 2 611 participants

Safety and Immunogenicity of H1N1 Vaccine With Trivalent Inactivated Seasonal Influenza Vaccine in Adults

GlaxoSmithKline

NCT00985673

COMPLETED Phase 3 602 participants

Safety and Reactogenicity of FluBlok and Comparison of Immunogenicity, Efficacy and Effectiveness Against TIV

Protein Sciences Corporation

NCT00539864

COMPLETED Phase 2 600 participants

A Study of Influenza Virus Vaccines in Children and Adults

Sanofi Pasteur, a Sanofi Company

NCT00988143

COMPLETED Phase 1 600 participants

H5 Vaccine Alone or With Aluminum Hydroxide in Elderly Adults

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00294099

COMPLETED Phase 1 581 participants

Study on Two Adjuvanted Dose Levels of Panblok H7+MF59 Compared for Immunogenicity and Safety With an Unadjuvanted Dose of Panblok H7 in Participants 18 Years of Age and Older

Sanofi Pasteur, a Sanofi Company

NCT05608005

COMPLETED Phase 2 531 participants

Sanofi Pasteur, TIV + H1N1, Pediatric Population

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00943202

COMPLETED Phase 2 530 participants

Dose-Finding Study of Favipiravir in the Treatment of Uncomplicated Influenza

MDVI

NCT01068912

COMPLETED Phase 2 520 participants

Study of Inactivated, Split-Virion Influenza Vaccine Compared With Standard Fluzone Vaccine in Infants and Children

Sanofi

NCT00391391

COMPLETED Phase 1 517 participants

H5N1 (Clade 2) Vaccination of Adults and Elderly

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00680069

COMPLETED 507 participants

Fluarix/ FluLaval/ Fluarix Quadrivalent/ FluLaval Quadrivalent Vaccine Pregnancy Registry

GlaxoSmithKline

NCT02148211

COMPLETED Phase 4 498 participants

Xofluza-Wearables Feasibility-Study

Children's Hospital of Philadelphia

NCT06161454

COMPLETED Phase 2 408 participants

CSL H1N1 Influenza Vaccine Administered at Two Dose Levels in Adult and Elderly Populations

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00943488

COMPLETED Phase 3 363 participants

Study to Assess Efficacy and Safety of Baloxavir Marboxil In Combination With Standard-of-Care Neuraminidase Inhibitor In Hospitalized Participants With Severe Influenza

Hoffmann-La Roche

NCT03684044

COMPLETED Phase 1 353 participants

Reverse Genetic H9N2 Influenza Vaccine Study in Adults

Alachua Government Services

NCT01320696

COMPLETED Phase 4 345 participants

Trial to Assess the Shedding,Immunogenicity, and Safety of FluMist Administered to Healthy Individuals 5-49 Years of Age

MedImmune

NCT00192140

COMPLETED NA 339 participants

Cell-Mediated Immune Responses to Influenza A/H5N1 Vaccine

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00311727

COMPLETED Phase 2 337 participants

H5 Booster After a Two Dose Schedule

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00240968

COMPLETED 336 participants

Audio Data Collection for Identification and Classification of Coughing

HealthMode

NCT04326309

COMPLETED Phase 4 326 participants

A Study to Evaluate the Safety of HIN1 Monovalent Vaccine (MEDI3414) in Children 2 to 17 Years of Age

MedImmune

NCT00946101

COMPLETED Phase 2 316 participants

Study to Evaluate Immunogenicity and Safety of GlaxoSmithKline (GSK) Biologicals' Quadrivalent Influenza Vaccine GSK2282512A When Administered to Children From 6 to 35 Months of Age

GlaxoSmithKline

NCT01974895

COMPLETED Phase 2 315 participants

Efficacy and Safety of Norketotifen in Uncomplicated Influenza-like Illness

Emergo Therapeutics

NCT04610047

COMPLETED Phase 4 301 participants

Study to Evaluate the Safety of 1 New 6:2 Influenza Virus Reassortant in Adults for the 2016-2017 Season

MedImmune

NCT02743117

COMPLETED Phase 4 301 participants

Study to Evaluate the Safety of 3 New 6:2 Influenza Virus Reassortants in Adults for the 2015-2016 Season

MedImmune

NCT02473510

COMPLETED Phase 4 300 participants

Study to Evaluate the Safety of 1 New 6:2 Influenza Virus Reassortant in Adults for the 2017-2018 Season

MedImmune

NCT03158038

COMPLETED Phase 3 300 participants

Study to Evaluate the Safety of a Bivalent Vaccine of New 6:2 Influenza Virus Reassortants in Healthy Adults

MedImmune

NCT00125944

COMPLETED Phase 4 300 participants

Study of Fluzone® Influenza Virus Vaccine 2011-2012 Formulation (Intramuscular Route) Among Adults

Sanofi Pasteur, a Sanofi Company

NCT01430819

COMPLETED Phase 1 270 participants

H5N1 Mix and Match With MF59

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01317745

COMPLETED Phase 1 243 participants

Comparison of Flu Vaccine Doses in Children

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01164553

COMPLETED Phase 4 241 participants

Gene Signatures of Influenza Vaccine Responses in Older Adults

Mayo Clinic

NCT03603509

COMPLETED Phase 4 240 participants

Safety and Immunogenicity of Fluzone® Quadrivalent and Fluzone® High-Dose, Influenza Vaccines

Sanofi Pasteur, a Sanofi Company

NCT03308825

COMPLETED NA 222 participants

Influenza Vaccine Randomized Educational Trial: Adult

Columbia University

NCT02907645

COMPLETED Phase 3 219 participants

Safety, Reactogenicity and Immunogenicity of Flublok Quadrivalent (Recombinant Influenza Vaccine,Seasonal Formulation)

Protein Sciences Corporation

NCT01959945

COMPLETED Phase 2 217 participants

Immunogenicity and Safety of Different Doses of Fluzone® Influenza

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00253734

COMPLETED Phase 4 208 participants

Study of Fluzone® Quadrivalent, Fluzone® Intradermal Quadrivalent, and Fluzone® High-Dose, Influenza Vaccines in Adults

Sanofi Pasteur, a Sanofi Company

NCT02563093

COMPLETED 203 participants

Cellular and Molecular Characterization of the Immune Response in Healthy NIH Employees atBaseline, and After Immunization With the H1N1 or Seasonal Influenza Vaccines

National Heart, Lung, and Blood Institute (NHLBI)

NCT01191853

COMPLETED Phase 1 200 participants

Safety and Immune Response Study of GSK Biologicals' Influenza Virus Vaccine 1388442A Compared With Fluarix

GlaxoSmithKline

NCT00693706

Phase Distribution

PhaseTrial count
Phase 1 42
Phase 2 31
Phase 3 17
Phase 4 25

Source: ClinicalTrials.gov, National Library of Medicine. Data is informational only.

Reading the Influenza Trial Landscape

ClinicalTrials.gov lists 157 US studies indexed under Influenza, and 27 of those are currently open to recruitment — roughly 17% of the total volume on the registry. That ratio is a useful proxy for activity level: a high share of recruiting studies often signals that research interest is current and that new enrollment opportunities are appearing, while a low share typically means the field is dominated by completed or follow-up work where most participant spots have already been filled. These counts reflect the public registry only and include studies at every stage of design, so they should be read as an index of research attention rather than as a measure of treatment availability.

The phase distribution for Influenza shows 42 late-stage studies (Phase 3 and Phase 4 combined) alongside 73 earlier-phase entries (Phase 1 through Phase 2). Phase 1 and Phase 2 studies focus on early safety signals, dosing, and preliminary effect, while Phase 3 studies are typically the larger efficacy and safety trials submitted toward regulatory review, and Phase 4 studies follow approved interventions in real-world use. A condition weighted toward later phases often reflects a mature research pipeline with several interventions already close to or past approval, whereas a heavier early-phase tilt suggests the field is still exploring new mechanisms and candidate approaches.

Top sponsor activity for Influenza is led by National Institute of Allergy and Infectious Diseases (NIAID) with 36 indexed trials, alongside 9 other organizations in the top contributor list. The list on this page surfaces up to 100 of the most relevant recent and active entries, ordered with recruiting studies first so practical options are visible. All figures are derived from the public ClinicalTrials.gov dataset maintained by the National Library of Medicine and are reproduced here for reference. Inclusion of a trial, sponsor, or intervention on this page is neither an endorsement nor a recommendation — eligibility, protocol changes, and site-level status can shift frequently, so always verify current details on ClinicalTrials.gov and consult a qualified healthcare provider before acting on anything you see here.

Frequently Asked Questions

How many clinical trials are there for Influenza?

PlainTrial tracks 157 US clinical trials for Influenza, of which 27 are currently recruiting participants. Data sourced from ClinicalTrials.gov.

How do I find a recruiting trial for Influenza?

Use the trial list above filtered by "Recruiting" status, or visit our trial finder at /recruiting to search by condition and state. Always discuss trial participation with your healthcare provider before enrolling.

Is this data current?

Data is sourced from ClinicalTrials.gov and reflects our most recent data pull. Trial status may have changed since then. Always verify current information at ClinicalTrials.gov before making decisions about participation.

Related

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from ClinicalTrials.gov (National Library of Medicine). Consult a qualified professional before making decisions based on this data.

Source: ClinicalTrials.gov (NIH/NLM) ClinicalTrials.gov AACT registry · 2026 Trial counts and statuses sourced from ClinicalTrials.gov. Sponsor counts include both industry and federal/academic sponsors.

Verify with NIH →