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Study on the Safety and Immune Response of a New Influenza Vaccine with GSKVX000000034794 in Healthy Younger and Older Adults

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a vaccine for the prevention of influenza, commonly known as the flu. The study involves healthy volunteers, both younger and older adults, to evaluate the safety and immune response of the vaccine. The vaccine being tested is an mRNA-based multivalent seasonal influenza vaccine, which means it is designed to protect against multiple strains of the flu virus using a technology that instructs cells to produce a protein that triggers an immune response.

The purpose of the study is to find and confirm the appropriate dose of the vaccine and to assess its safety and how well it triggers an immune response. Participants will receive the vaccine through an injection into the muscle. Some participants may receive a placebo, which is a substance with no active ingredients, to compare the effects. The study will monitor participants for any side effects and measure their immune response over several months.

Throughout the study, participants will be asked to attend follow-up visits to check their health and collect data on their immune response. The study aims to ensure that the vaccine is safe and effective in preventing influenza infection in healthy individuals. This research is important for developing better flu vaccines that can protect more people from getting sick during flu season.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial visit and consent

    Upon joining the study, participants will attend an initial visit. During this visit, a detailed explanation of the study will be provided, and any questions will be addressed.

    Participants will be required to provide written informed consent, confirming their understanding and willingness to participate in the study.

  2. Step 2

    Eligibility assessment

    Participants will undergo a medical history review and a clinical examination to ensure they meet the study's eligibility criteria.

    Safety laboratory assessments will be conducted to confirm the participant's health status.

  3. Step 3

    Study intervention administration

    Eligible participants will receive the study intervention, which is a vaccine against influenza, administered via an intramuscular injection.

    The vaccine is designed to prevent influenza infection and is given as a single dose.

  4. Step 4

    Monitoring and follow-up

    Participants will be monitored for any immediate reactions following the vaccine administration.

    Participants will be required to complete an electronic diary (eDiary) to record any symptoms or side effects experienced from Day 1 to Day 7.

  5. Step 5

    Follow-up visits

    Participants will return for follow-up visits to assess their health and the immune response to the vaccine.

    These visits will occur on Day 8, Day 29, Day 92, and Day 183.

  6. Step 6

    Safety and immune response evaluation

    The study will evaluate the safety of the vaccine by monitoring for any adverse events from Day 1 to Day 183.

    The immune response will be assessed by measuring antibody levels at specified intervals, including Day 29, Day 92, and Day 183.

Who can join the trial?

7 criteria

  • Participants must be between 18 and 50 years old for Phase 1, and between 18 and 85 years old for Phase 2.
  • Participants should be healthy or have medically stable conditions. This means their health issues are not getting worse and do not require major changes in treatment or hospital visits in the last 3 months.
  • Participants must have a Body Mass Index (BMI) between 18 kg/m² and 35 kg/m². BMI is a measure of body fat based on height and weight.
  • Participants should be able to follow the study requirements, like filling out an electronic diary and attending follow-up visits.
  • Participants must provide written informed consent before any study procedures. This means they agree to participate after understanding the study details.
  • Female participants who cannot have children can join the study.
  • Female participants who can have children can join if they have used effective birth control for 28 days before the study, have a negative pregnancy test on the day of the study, and agree to use birth control for at least 1 month after the study.

Who cannot join the trial?

9 criteria

  • Participants must not have any current or past medical conditions that could interfere with the study.
  • Participants should not have a history of severe allergic reactions, especially to vaccines.
  • Participants must not be currently participating in another clinical trial.
  • Participants should not have received any other vaccine within the last 30 days.
  • Participants must not have a weakened immune system, which means their body has a reduced ability to fight infections.
  • Participants should not be pregnant or planning to become pregnant during the study period.
  • Participants must not have any acute illness or fever at the time of enrollment.
  • Participants should not have a history of drug or alcohol abuse.
  • Participants must not have any condition that, in the opinion of the study doctor, could affect their ability to participate in the study.
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Investigated drugs

mRNA-based multivalent seasonal influenza vaccine candidates are new types of vaccines being tested to protect against the flu. These vaccines use a small piece of genetic material called mRNA to help the body recognize and fight the flu virus. The goal is to see if these vaccines are safe and if they can help the immune system respond to the flu virus in both younger and older adults. The study is looking at how well these vaccines work and if they cause any side effects.

What is already known about the treatment

mRNA-based multivalent seasonal influenza vaccine candidates – This investigational vaccine is administered through an injection, typically into the muscle, to help prevent influenza infection in healthy individuals. Currently, it is being studied in clinical trials to assess its safety, how well it is tolerated, and its ability to trigger an immune response. The vaccine is designed to protect against multiple strains of the flu virus by using mRNA technology, which instructs cells in the body to produce proteins that mimic parts of the virus, thereby stimulating the immune system to recognize and fight the actual virus if encountered. This vaccine falls under the category of preventive vaccines, specifically targeting seasonal influenza.

Investigated diseases

Influenza – Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. It primarily affects the nose, throat, and sometimes the lungs. The disease typically begins suddenly and is characterized by symptoms such as fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and fatigue. In some cases, it can lead to more severe complications, especially in young children, elderly adults, and individuals with certain chronic health conditions. The virus spreads mainly through droplets made when people with the flu cough, sneeze, or talk. The progression of the disease can vary, with most people recovering within a few days to less than two weeks.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2022-502308-66-00Protocol code217884Estimated enrolment1 272 patientsSponsorGlaxoSmithKline Biologicals

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

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