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Immune response and safety of revaccination with respiratory syncytial virus glycoprotein F recombinant vaccine adjuvanted with AS01E in older adults

Verified siteRegistered drugNo placebo
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What is this trial about?

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

The study focuses on infections caused by Respiratory Syncytial Virus, a common virus that can lead to serious breathing problems especially in older adults. Participants will receive a single dose of an investigational vaccine called RSVPreF3, which is given as an injection into the muscle. The vaccine contains a piece of the virus that has been engineered to look like the natural form and includes an “adjuvant,” a substance that helps the immune system respond more strongly.

The purpose of the study is to see how well the vaccine stimulates the body’s defenses and to confirm that it is safe to use. After receiving the injection, participants will have blood tests a short time later to measure the level of protective antibodies, and they will be monitored for any side effects for up to a year. Visits are scheduled at the start of the study, a few weeks later, and then periodically during the follow‑up period, with simple procedures such as blood draws and brief health questionnaires.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial Visit and Consent

    You attend the first study visit after joining the trial and sign the informed consent form that explains the study purpose and procedures.

    A blood sample is taken to establish your baseline immune status before receiving any study medication.

  2. Step 2

    Vaccination Administration

    You receive a single intramuscular injection of Arexvy vaccine, which contains 120 µg of a recombinant respiratory syncytial virus (RSV) glycoprotein F protein adjuvanted with AS01E to enhance the immune response.

    The injection is given in the upper arm muscle and is the only dose of study medication you will receive during the trial.

  3. Step 3

    Immediate Safety Observation

    After the injection you remain at the study site for about 30 minutes while staff monitor you for any immediate reactions such as fever, pain at the injection site, or allergic signs.

  4. Step 4

    Day 1 Follow‑Up Visit

    One day after vaccination you return for a brief visit during which another blood sample is collected to measure neutralizing antibodies against RSV‑A and RSV‑B.

    You are asked about any side effects you may have experienced since the injection, including fever, headache, or injection‑site soreness.

  5. Step 5

    Day 29 Follow‑Up Visit

    Twenty‑nine days after vaccination you attend a second follow‑up visit.

    A blood sample is taken again to assess how your immune system is responding to the vaccine, and you are questioned about any adverse events that occurred during the past month.

  6. Step 6

    Month 6 Safety Check

    Six months after the vaccination you have a safety assessment visit.

    The study team reviews any serious adverse events (SAEs) that may have occurred and records your health status.

  7. Step 7

    Month 12 Final Visit

    Twelve months after the vaccination you complete the final study visit.

    The visit includes a safety review for any related serious adverse events that might have arisen up to the end of the study and concludes your participation.

Who can join the trial?

5 criteria

  • You must be able to follow all the study rules and instructions.
  • You need to sign a written agreement (called informed consent) before any study procedures are done.
  • You should be in good health and stable when you join the study. This means if you have long‑term conditions like diabetes (high blood sugar), hypertension (high blood pressure), or heart disease, they must be under control and not getting worse.
  • You must have received a vaccine for Respiratory Syncytial Virus (RSV) before you join the study.
  • You must be at least 70 years old at the time you received the RSV vaccine, regardless of whether you are male or female.

Who cannot join the trial?

19 criteria

  • History of an allergic reaction (hypersensitivity) that could get worse because of any part of the vaccine.
  • Had a serious health problem (serious adverse event (SAE)) or a possible immune‑system problem caused by a previous RSV vaccine (potential immune‑mediated disorder (pIMD)), including allergic reactions, that might be linked to that vaccine or other vaccines.
  • Developed a new immune‑system problem or a worsening of a previous one after an RSV vaccine, putting you at an unacceptable risk for another vaccination.
  • Used any experimental or not‑yet‑approved medicine (other than the study vaccine).
  • Received antibody preparations from donated blood (immunoglobulins) or other blood or plasma products.
  • Are taking, or plan to take, medicines that change how the immune system works (immune‑modifying drugs) or long‑acting immune‑modifying treatments.
  • Plan to receive, or have already received, a vaccine that is not allowed by the study plan.
  • Are taking part in another clinical study at any time during this study.
  • Have a history of, or currently use, chronic alcohol or drug abuse, as judged by the doctor.
  • Are study staff members or an immediate family member, household member, or dependent of study staff.
  • Are unable to get out of bed (bedridden).
  • Have a confirmed or suspected condition that weakens the immune system (immunosuppressive or immunodeficient) based on medical history and physical exam.
  • Have a sudden (acute) or unstable long‑term illness, as determined by physical examination.
  • Show significant abnormal blood test results (hematologic means related to blood).
  • Have repeated or uncontrolled nerve or brain problems, such as nerve inflammation, birth‑related brain conditions, brain disease (encephalopathies), or seizures.
  • Have any other medical condition that could increase the risk of taking part in the study.
  • Have a condition that would make an injection into the muscle unsafe.
  • Have a serious underlying illness that would likely prevent finishing the study.
  • Have a history of dementia or any condition that seriously reduces thinking ability or understanding of the consent form and study procedures.
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Investigated drugs

Arexvy is a vaccine that helps the body build protection against respiratory syncytial virus (RSV), a virus that can cause serious lung infections, especially in older adults. It is given as a small amount of liquid that is injected into a muscle. The vaccine contains a specially shaped piece of the virus’s surface protein (glycoprotein F) that teaches the immune system to recognize and fight the real virus. It also includes an ingredient called an adjuvant (AS01E) that makes the immune response stronger. In this study, participants receive a revaccination dose of Arexvy so researchers can see how well the immune system responds again and check that the vaccine remains safe.

What is already known about the treatment

Arexvy - This vaccine is given as a suspension that is injected into the muscle (intramuscular use). It is an approved medication that is used to protect older adults from respiratory syncytial virus (RSV) infection. The vaccine contains a lab‑made version of the RSV F protein locked in its prefusion shape, combined with the AS01E adjuvant to boost the body’s immune response. It is classified as an adjuvanted recombinant viral vaccine.

Investigated diseases

Respiratory syncytial virus infection (RSV infection) - Respiratory syncytial virus infection is a common viral illness that affects the lining of the airways. It typically begins with symptoms such as runny nose, cough, and mild fever. In many cases the infection spreads to the lower airways, causing bronchiolitis and wheezing. Young infants and older adults are more likely to develop more extensive airway inflammation. The disease can progress from mild upper‑respiratory signs to difficulty breathing as the virus damages the small airways.
Trial detailsLast updated 15 Nov 2026
Age65+ yearsPhasePhase IITrial ID2026-526726-40-00Protocol code307347Estimated enrolment80 patientsSponsorGlaxoSmithKline Biologicals

sourced from the EU Clinical Trials Register and site verification

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