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ClinicalTrials.gov 27 recruiting now early-phase tilt #70 of 28,707 conditions

Influenza: early-phase trial registry

27 of 157 indexed Influenza trials are currently recruiting, with more weight in Phase 1-2.

Corpus placement: #70 of 28,707 conditions by registered trial count.

157 US clinical trials · 27 currently recruiting · #70 of 28,707 conditions by registered trial count

Influenza: 157 US clinical trials tracked, 27 recruiting.

Influenza is the subject of 157 registered US clinical trials on ClinicalTrials.gov, 27 of them currently open to new participants. 42 are in Phase 3-4 (later-stage) and 73 in Phase 1-2 (earlier-stage). The most active sponsor is National Institute of Allergy and Infectious Diseases (NIAID), running 36 of these trials.

Enrollment posture brief

Registry condition influenza

OPEN 27 | RECR 17% | LATE 42 | EARLY 73 | RANK #70 | SPON 36

Nearest open-share peer: Arthritis, Rheumatoid (17% recruiting · 29 trials)

PTSD49.7%Gastric Cancer45.3%Obstructive Sleep Apnea42%Neoplasms31.3%Influenza (this)17%
Open-enrollment share among volume-matched conditions near Influenza

Influenza lists 27 open slots (17% of 157 indexed trials). Peers are matched on registered volume, not therapeutic-area browse lists. How peer matching works →

Key findings

What ClinicalTrials.gov does not surface for Influenza on its own pages , computed from the registry mirror as of 2026-08-08. Each line carries its own denominator so it can be quoted as it stands.

  1. Influenza is recruiting below its size-band peers.

    27 of 157 indexed trials (17.2%) are open to enrollment, against a 37.1% average across 139 conditions with 100+ trials. The peer set uses the same ClinicalTrials.gov-derived counts as this page.

  2. One sponsor concentrates Influenza research.

    National Institute of Allergy and Infectious Diseases (NIAID) accounts for 36 of 157 trials (22.9%). 62 distinct sponsors appear on at least one study for this condition label.

  3. Typical Influenza enrolment sits around 219 participants.

    Median target enrolment is 219 among the 157 trials that report a genuine target (sentinel values excluded). 55 of those (35%) plan for fewer than 100 participants.

  4. Influenza research is mostly interventional.

    134 interventional and 23 observational studies make up this index (85.4% interventional). Study type is sponsor-reported on ClinicalTrials.gov.

Phase 142Phase 231Phase 317Phase 425

Open and recent trials

157 total, page 3 of 4

COMPLETED Phase 2 183 participants

2010-2011 Trivalent Influenza Vaccine (TIV) in Pregnant Women

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01173211

COMPLETED Phase 2 179 participants

A Phase 2 Influenza A Challenge Study Following Oral Administration of an H1N1 HA Ad-Vector Seasonal Flu Vaccine

Vaxart

NCT02918006

COMPLETED Phase 3 173 participants

Study to Assess the Safety, Pharmacokinetics, and Efficacy of Baloxavir Marboxil in Healthy Pediatric Participants With Influenza-Like Symptoms

Hoffmann-La Roche

NCT03629184

COMPLETED Phase 1 156 participants

Immunogenicity and Safety of FluBlok Trivalent Recombinant Hemagglutinin Influenza Vaccine in Healthy Pediatrics

Protein Sciences Corporation

NCT00336453

COMPLETED Phase 1 152 participants

A Study Evaluating the Safety and Tolerability of a Seasonal Influenza Vaccine Containing LIQ001

Liquidia Technologies

NCT01224262

COMPLETED Phase 1 150 participants

Safety and Immunogenicity of Quadrivalent Recombinant Influenza Vaccine Formulations Containing Different H3 Hemagglutinin Antigens in Healthy Adult Subjects 18 to 30 Years of Age

Sanofi Pasteur, a Sanofi Company

NCT04144179

COMPLETED Phase 4 150 participants

Proteomic Profiling for Influenza

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00133588

COMPLETED Phase 2 150 participants

Study of an Investigational Monoclonal Antibody, VIS410, in Subjects With Uncomplicated Influenza A

Visterra

NCT02989194

COMPLETED NA 140 participants

Influenza Vaccination in the Emergency Department

University of Arizona

NCT00822627

COMPLETED Phase 3 137 participants

Safety, PK and Effectiveness of IV Peramivir Versus Oseltamivir in Pediatric Subjects With Uncomplicated Influenza

BioCryst Pharmaceuticals

NCT02369159

COMPLETED Phase 1 131 participants

Seasonal Influenza DNA Vaccine Prime With Trivalent Inactivated Vaccine (TIV) Boost Compared to TIV Alone

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01498718

COMPLETED Phase 1 126 participants

Safety, Reactogenicity, and Immunogenicity of Inactivated Influenza A/H7/N7 Vaccine in Healthy Adults

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00546585

COMPLETED 122 participants

Influenza Vaccine in Lung Transplant Patients - Antibody

University of Wisconsin, Madison

NCT04533139

COMPLETED Phase 4 120 participants

A Study to Evaluate the Safety and Immune Responses to Fluzone® Vaccination

Sanofi Pasteur, a Sanofi Company

NCT00743275

COMPLETED NA 107 participants

Immunologic Response to Inactivated Vaccine for Novel H1N1 Virus

University of Rochester

NCT01023711

COMPLETED Phase 2 102 participants

Influenza Vaccine in Pregnant Women

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00905125

COMPLETED Phase 1 100 participants

Safety and Dose Study of Peramivir for Influenza Treatment

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00297050

COMPLETED Phase 1 96 participants

Inactivated Influenza A/H9N2 Vaccine With and Without MF59 Adjuvant in Ambulatory Adults

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00133471

COMPLETED Phase 4 90 participants

Collection of Serum Samples From Children and Older Adults Receiving the 2019-2020 Formulations of Fluzone® Quadrivalent and Fluzone® High-Dose Influenza Vaccines, Respectively

Sanofi Pasteur, a Sanofi Company

NCT04109222

COMPLETED 87 participants

Sanofi Pasteur Quadrivalent Intradermal Influenza Vaccine Pregnancy Registry

Sanofi Pasteur, a Sanofi Company

NCT02554409

COMPLETED Phase 1 87 participants

Oseltamivir Treatment for Children Less Than 24 Months of Age With Influenza

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00391768

COMPLETED Phase 4 86 participants

Plasmablast Trafficking and Antibody Response in Influenza Vaccination (SLVP021 2011-2014)

Stanford University

NCT02141581

COMPLETED Phase 2 82 participants

Mucosal and Systemic Immunity After Viral Challenge of Healthy Volunteers Vaccinated With Inactivated Influenza Vaccine Via the Intranasal Versus Intramuscular Route

National Institute of Allergy and Infectious Diseases (NIAID)

NCT03845231

COMPLETED Phase 1 80 participants

The Role of CD4+ Memory Phenotype, Memory, and Effector T Cells in Vaccination and Infection

Stanford University

NCT03453801

COMPLETED Phase 4 72 participants

T-cell And General Immune Response to Seasonal Influenza Vaccine (SLVP018) - Year 1, 2009

Stanford University

NCT01987349

COMPLETED Phase 1 68 participants

Safety, Tolerability, and PK of Escalating Doses of Flufirvitide-3 Dry Powder for Inhalation in Healthy Subjects

Autoimmune Technologies

NCT01990846

COMPLETED Phase 4 60 participants

Safety and Immunogenicity Among Healthy Children Receiving Fluzone® Quadrivalent Influenza Virus Vaccine

Sanofi Pasteur, a Sanofi Company

NCT01946425

COMPLETED Phase 4 60 participants

Safety and Immunogenicity Among Healthy Children Receiving Fluzone® Quadrivalent, Influenza Vaccine

Sanofi Pasteur, a Sanofi Company

NCT02222870

COMPLETED Phase 2 60 participants

Single-ascending-dose Study of the Safety and Immunogenicity of NasoVAX

Altimmune

NCT03232567

COMPLETED 60 participants

Elderly Influenza Vaccine Immunogenicity Substudy

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00170482

COMPLETED NA 58 participants

Evaluation of Free Air Portable Air Powered Respirator

Wake Forest University Health Sciences

NCT02487147

COMPLETED Phase 1 56 participants

Phase 1 Safety and Immunogenicity Study in Healthy Adults of VAX125, a Recombinant HA-flagellin Influenza Vaccine

VaxInnate Corporation

NCT00730457

COMPLETED Phase 2 52 participants

Study to Evaluate the Immune Responses of Trivalent Cold-Adapted Influenza Vaccine (CAIV-T) Compared With (TIV)

MedImmune

NCT00111579

COMPLETED Phase 1 51 participants

Study of High-dose Influenza Vaccine Efficacy by Repeated Dosing In Gammopathy Patients

Yale University

NCT02267733

COMPLETED Phase 4 51 participants

B-cell Immunity to Influenza (SLVP017)- Year 1, 2009

Stanford University

NCT02133781

COMPLETED Phase 3 50 participants

Safety and Tolerability Study of GlaxoSmithKline (GSK)1557484A Vaccine in Adults at Occupational Risk for Influenza A (H5N1) Exposure

GlaxoSmithKline

NCT01788228

COMPLETED Phase 1 49 participants

Influenza A 2009 H1N1 Challenge Study in Healthy Adults

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01646138

COMPLETED Phase 1 43 participants

Immune Responses to H5N1 Vaccine With and Without AS03 Adjuvant

National Institute of Allergy and Infectious Diseases (NIAID)

NCT01578317

COMPLETED Phase 1 41 participants

A Study of VIS410 to Assess Safety and Pharmacokinetics

Visterra

NCT02045472

COMPLETED Phase 4 34 participants

Effect of Age and Prior Immunity to Response to Seasonal Influenza Vaccines in Children

University of Rochester

NCT01246999

COMPLETED Phase 4 34 participants

Phase IV Trial to Collect Safety Data and Sera for Immunogenicity Testing in Healthy Children Given Fluzone® Vaccine

Sanofi Pasteur, a Sanofi Company

NCT00561002

COMPLETED Phase 2 31 participants

Phase II Study to Investigate the Kinetics of the Immune Response Generated by Influenza Virus Vaccine.

MedImmune

NCT00192309

COMPLETED Phase 1 31 participants

Anti-Influenza Hyperimmune Intravenous Immunoglobulin Pilot Study (INSIGHT 005: Flu-IVIG Pilot)

National Institute of Allergy and Infectious Diseases (NIAID)

NCT02008578

COMPLETED Phase 1 30 participants

Safety of and Immune Response to a Bird Flu Virus Vaccine (H9N2) in Healthy Adults (Study A)

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00110279

COMPLETED Phase 1 30 participants

Safety of Lactobacillus Rhamnosus GG Versus Placebo in Elderly Subjects Receiving Live Attenuated Influenza Vaccine

Patricia L. Hibberd

NCT01545349

COMPLETED Phase 2 27 participants

H7N9 Boost in Healthy Adults

National Institute of Allergy and Infectious Diseases (NIAID)

NCT02586792

COMPLETED Phase 1 27 participants

Safety, Tolerability, and Pharmacokinetics of SAB-176 in Healthy Participants

SAb Biotherapeutics

NCT04471038

COMPLETED Phase 1 22 participants

Safety and Immune Response to Recombinant Live-Attenuated Influenza H2N2 Virus Vaccine

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00722774

COMPLETED Phase 1 22 participants

Safety of Synbiotics as Adjuvant to Influenza Vaccine in Elderly

Mayo Clinic

NCT01304771

COMPLETED Phase 1 22 participants

Safety of and Immune Response to Recombinant Live-Attenuated Influenza H6N1 Virus Vaccine Vaccine

National Institute of Allergy and Infectious Diseases (NIAID)

NCT00734175

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Phase Distribution

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

Named interventions

Most-linked intervention names on Influenza records (sponsor-reported on ClinicalTrials.gov). Counts are trial links, not unique products.

Placebo Biological
7 trials
Fluzone® Biological
5 trials
Oseltamivir Drug
5 trials
Baloxavir Marboxil Drug
5 trials
Placebo Drug
5 trials
Placebo Other
4 trials
Inactivated H1N1 Vaccine Biological
3 trials
GSK2340273A Biological
3 trials

US sites by state

Facility locations filed on Influenza trials. A trial with sites in several states counts in each.

California 45 trials
Maryland 34 trials
Texas 33 trials
Florida 32 trials
Georgia 30 trials
Ohio 29 trials
New York 27 trials
Missouri 26 trials

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

What to do with this Influenza page

157 registered trials, 27 currently recruiting, is a starting point for a conversation, not a diagnosis or a recommendation.

Trial and recruiting counts reflect ClinicalTrials.gov registry status as of the data vintage above; individual trial eligibility and enrollment status can change.

Every figure on PlainTrial is rendered directly from the ClinicalTrials.gov registry, no number is typed in by an editor. This Influenza condition card totals 157 registered trials; most-linked intervention Placebo; top US site state California. See our editorial standards & corrections policy, the methodology behind these numbers, the data changelog, or report a data error.