Influenza undergoes strain-specific changes annually, necessitating continuous research to better understand the impact of each strain across diverse patient populations. Clinicians can maintain optimal patient care by staying informed on emerging evidence from ongoing clinical trials.

Today, we are featuring six actively recruiting clinical trials in the United States investigating influenza vaccines across patient populations, including pediatric and elderly transplant recipients.

Overview of the Featured Influenza Vaccine Clinical Trials
Study TitlePhaseEstimated EnrollmentStart DateEstimated Primary Completion
A Phase I/​II Study on Safety AND Immunogenicity of AZD4117 and AZD5315 Vaccines (PANDA) (PANDA)1,2400September 2025January 2026
A Study to Learn About How the Flu and COVID-19 Vaccines Act in Healthy People1,2 2645February 2025December 2025
A Study to Find and Confirm the Dose and Assess Safety, Reactogenicity and Immune Response of a Vaccine Against Pandemic H5N1 Influenza Virus in Healthy Younger and Older Adults1,2 996April 2024August 2025
A Clinical Study to Evaluate the Efficacy, Safety and Immunogenicity of an Adjuvanted Influenza Vaccine Compared to a Non-adjuvanted Influenza Vaccine in Adults ≥65 Years of Age335800October 2023November 2026
High vs.Standard Dose Influenza Vaccine in Pediatric Solid Organ Transplant (SOT) Recipients (PSOT)2312September 2024July 2027
High vs. Standard Dose Influenza Vaccine in Lung Allograft Recipients2270November 2022July 2027
Influenza Vaccines: Currently Recruiting Clinical Trials 

A Phase I/​II Study on Safety AND Immunogenicity of AZD4117 and AZD5315 Vaccines (PANDA) (PANDA)

  • Sponsor: AstraZeneca
  • Goal: The purpose of this study is to evaluate the safety and immunogenicity of two investigational vaccines, AZD4117 and AZD5315 to protect against certain strains of avian Influenza A (H5N1 and H7N9 subtypes).
  • Interventions: AZD4117, AZD5315, Placebo
  • Primary Outcome Measure; Timeframe:
    • Percentage of participants with immediate unsolicited adverse events (AE); Within 30 minutes after dosing.
    • Percentage of participants with injection site and systemic solicited adverse reactions (AR); Through seven days after dosing.
    • Percentage of participants with unsolicited AE; Through 28 days after the last dose.
    • Percentage of participants with serious adverse events (SAE); Through 12 months after the last dose.
    • Percentage of participants with medically attended adverse events (MAAE); Through 12 months after the last dose.
    • Percentage of participants with adverse events of special interest (AESI); Through 12 months after the last dose.
    • Proportion of participants achieving ≥ 1:40 HAI titer post-IMP administration; Day 58.
    • Proportion of participants achieving seroconversion post-IMP administration; Day 58.
  • Study Details
  • Source

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

  • Sponsor: BioNTech SE
  • Goal: The purpose of this study is to learn about how the flu and COVID vaccines act when given alone or when mixed together.
  • Interventions: Investigational influenza vaccine, Investigational COVID-19 vaccine, Investigational influenza and COVID-19 combination vaccine, Licensed influenza vaccines (1, 2, and 3), Licensed COVID-19 vaccine
  • Primary Outcome Measure; Timeframe: 
    • Percentage of participants reporting prompted local reactions within 7 days following investigational product administration; Day seven.
    • Percentage of participants reporting prompted systemic events within 7 days following investigational product administration; Day seven.
    • Percentage of participants reporting adverse events (AEs) through 1 month following investigational product administration; One month.
    • Percentage of participants reporting serious adverse events (SAEs) through 6 months following investigational product administration; Six months.
  • Study Details
  • Source

A Study to Find and Confirm the Dose and Assess Safety, Reactogenicity and Immune Response of a Vaccine Against Pandemic H5N1 Influenza Virus in Healthy Younger and Older Adults

  • Sponsor: GlaxoSmithKline
  • Goal: The aim of this study is to evaluate the safety, reactogenicity and immunogenicity of the Flu Pandemic messenger RNA (mRNA) vaccine (including dose-finding and dose-confirmation) administered in healthy adults 18 to 85 years of age.
  • Interventions: Flu Pandemic mRNA_Dose levels (1, 2, 3, 4, 5, and 6), Influenza virus vaccine, Placebo
  • Primary Outcome Measure; Timeframe: There are 30 primary outcome measures and 30 associated timeframes. We encourage you to visit the full text page at the source link below to view the primary outcome measures and timeframes for this clinical trial in its entirety.
  • Study Details
  • Source

A Clinical Study to Evaluate the Efficacy, Safety and Immunogenicity of an Adjuvanted Influenza Vaccine Compared to a Non-adjuvanted Influenza Vaccine in Adults ≥65 Years of Age

  • Sponsor: Seqirus
  • Goal: The aim of the study is to evaluate MF59-adjuvanted influenza vaccine compared with non-adjuvanted influenza vaccine in the prevention of reverse transcription-polymerase chain reaction (RT-PCR)-confirmed influenza A and/or B in subjects ≥65 years of age.
  • Interventions: QIV pr TIV, aQIV or aTIV
  • Primary Outcome Measure; Timeframe: Efficacy Endpoint: First-occurrence of RT-PCR-confirmed influenza, due to any influenza Type A and/or B virus (regardless of antigenic match), using the protocol-defined ILI definition; From 14 days after vaccination (ie study day 15) and until the end of influenza season (typically end of May for Northern Hemisphere [NH] influenza season and end of November for Southern Hemisphere [SH] influenza season).
  • Study Details
  • Source

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

  • Sponsor: National Institute of Allergy and Infectious Diseases
  • Goal: This is a phase II, multi-center, double-blind, randomized controlled immunogenicity and safety trial comparing two doses of HD-QIV or two doses of SD-QIV in pediatric SOT recipients.
    Interventions: Standard dose quadrivalent inactivated influenza vaccine, High dose quadrivalent inactivated influenza vaccine
  • Primary Outcome Measure; Timeframe: 
    • Immunogenicity: Hemagglutination Inhibition (HAI) titers; Four weeks following the second study vaccine. 
    • Safety: solicited local and systemic post-administration reactions; In the first seven days following each study vaccine.
  • Study Details
  • Source

High vs. Standard Dose Influenza Vaccine in Lung Allograft Recipients

  • Sponsor: Vanderbilt University Medical Center
  • Goal: The proposed study is a phase II, multi-center, double-blind, randomized controlled immunogenicity and safety trial comparing two doses of HD-QIV to two doses of SD-QIV in lung allograft recipients.
  • Interventions: High dose quadrivalent inactivated influenza vaccine, Standard dose quadrivalent inactivated influenza vaccine
  • Primary Outcome Measure; Timeframe:
    • Geometric Mean Titers of influenza vaccine antibodies; Day 56 (post-vaccination).
    • The number of participants reporting solicited injection site reactions and systemic reactions; Within seven days post-vaccination.
    • The number of participants reporting solicited injection site reactions and systemic reactions; Within seven days post-vaccination.
  • Study Details
  • Source
Related Guidelines:

Use of Vaccines for the Prevention of Seasonal COVID-19, Influenza, and RSV Infections in Immunocompromised Patients

  • Infectious Diseases Society of America
  • November 2025

Adult Immunization Schedule by Age

  • Centers for Disease Control and Prevention
  • October 2025

Childhood and Adolescent Immunization Schedule

  • Centers for Disease Control and Prevention
  • January 2025

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