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Study of ExPEC9V vaccine for preventing invasive E.

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What is this trial about?

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

This study focuses on preventing Invasive Extraintestinal Pathogenic Escherichia coli Disease (a serious infection caused by E. coli bacteria that can spread beyond the urinary tract to other parts of the body) in adults aged 60 years and older who have had a urinary tract infection in the past two years. The study will test a new vaccine called ExPEC9V, which is given as an injection into the muscle, compared to a placebo.

The purpose of the study is to determine if the ExPEC9V vaccine can prevent infections caused by specific types of E. coli bacteria. The vaccine targets nine different strains of E. coli bacteria that commonly cause serious infections. During the study, participants will receive either the vaccine or a placebo injection and will be monitored for several years to track any infections that may develop.

The study will also look at how well the immune system responds to the vaccine by measuring antibody levels in the blood, monitor any side effects that may occur after vaccination, and assess how the vaccine impacts participants' quality of life. Participants will need to report any symptoms they experience and complete questionnaires about their health throughout the study period.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial vaccination

    You will receive a single dose of either ExPEC9V vaccine or placebo through an intramuscular injection

    The vaccination will be administered as a solution for injection

  2. Step 2

    Safety monitoring period - first 15 days

    If you are in the Safety Subset group, you will need to record any local reactions (at injection site) and general reactions in an electronic diary

    Local reactions may include pain, redness, or swelling at the injection site

    General reactions may include fever, headache, or fatigue

  3. Step 3

    Initial follow-up period - first 30 days

    You will need to report any unexpected medical issues that occur

    The study team will monitor your health status

  4. Step 4

    Long-term follow-up visits

    You will need to attend follow-up visits at Day 30, Day 181, Year 1, Year 2, Year 3, and Year 4

    If you are in the Immunogenicity Subset group, blood samples will be collected during these visits to measure antibody levels

    You will complete quality of life questionnaires using an electronic system

    Your overall health status will be assessed, including a frailty evaluation

  5. Step 5

    Ongoing monitoring throughout the study

    You will need to report any urinary tract infections (UTIs) or other infections that occur

    If you develop a serious infection, blood or other samples may need to be collected

    Any hospitalizations related to infections will be documented

    The total study duration will continue until June 2029

Who can join the trial?

15 criteria

  • Must be 60 years of age or older when signing the consent form
  • Must be available for the entire study duration and not planning to travel for more than 30 consecutive days
  • Must have had a urinary tract infection (UTI) in the past 2 years, confirmed by a doctor
  • If recently had UTI or acute bacterial prostatitis (prostate infection), it must be resolved for at least 14 days before study start
  • Must be medically stable, meaning:
    • No major changes in treatment in the past 6 weeks
    • No expected hospitalizations during the study period
    • Female participants must be either:
      • Post-menopausal (no longer having menstrual periods), or
      • Permanently unable to have children
      • Must have valid identification and be reachable during the study
      • Must be able to complete electronic questionnaires or agree to complete them with assistance from study staff
      • Must have at least one additional risk factor from the following:
        • Previous blood infection with E. coli bacteria
        • Hospital stay in the past 2 years
        • Complicated urinary tract infection
        • Previous kidney infection (pyelonephritis) resolved for at least 14 days
        • Current or previous prostate cancer or urinary tract tumors

Who cannot join the trial?

15 criteria

  • Age below 60 years or above 85 years
  • Previous vaccination with any E. coli vaccine
  • Currently participating in another clinical trial or within 30 days before enrollment
  • Any serious medical condition that could interfere with the study procedures
  • History of severe allergic reactions to vaccines or their components
  • Active infection requiring antibiotic treatment
  • Currently receiving immunosuppressive therapy (medications that weaken the immune system)
  • Blood disorders or conditions affecting blood clotting
  • Any condition that, in the investigator's opinion, makes the person unsuitable for the study
  • Pregnancy or breastfeeding
  • Unable to comply with study procedures or follow-up visits
  • History of drug or alcohol abuse within the past year
  • Mental conditions that could affect the ability to provide informed consent
  • Severe kidney or liver dysfunction
  • Current participation in another vaccine study
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Investigated drugs

ExPEC9V is a vaccine designed to prevent infections caused by specific types of E. coli bacteria. It targets nine different strains of extraintestinal pathogenic E. coli (ExPEC) that can cause serious infections. This vaccine is being studied for its ability to protect older adults who have had urinary tract infections from developing more severe E. coli-related infections that can spread to the blood or other parts of the body.

What is already known about the treatment

ExPEC9V – An investigational vaccine developed for preventing invasive extraintestinal pathogenic E. coli disease in older adults. The vaccine is administered through injection and targets nine specific O-serotypes of E. coli bacteria (O1, O2, O4, O6, O15, O16, O18, O25, and O75). Currently undergoing Phase 3 clinical trials, this preventive medication is specifically designed for adults aged 60 years and older with a history of urinary tract infections. The vaccine works by stimulating the immune system to produce antibodies against these specific E. coli strains, helping to prevent serious invasive infections that can spread beyond the urinary tract into the bloodstream and other sterile body sites.

Investigated diseases

  • Invasive Extraintestinal Pathogenic E. coli Disease (IED)

    A serious bacterial infection caused by specific strains of E. coli bacteria that spread beyond the intestinal tract to other parts of the body. The infection can affect various organs and tissues, including the blood, urinary tract, and other normally sterile sites in the body. The condition typically begins when these particular E. coli strains enter the bloodstream or other sterile body sites. It can progress to cause urinary tract infections, kidney infections (pyelonephritis), or more widespread infection. The bacteria responsible for this condition belong to specific strains identified by their O-serotypes, including O1, O2, O4, O6, O15, O16, O18, O25, and O75.

  • Pyelonephritis

    A kidney infection that occurs when bacteria travel up from the bladder through the ureters to infect the kidneys. It typically develops as a complication of a lower urinary tract infection. The infection causes inflammation in the kidneys and can affect one or both kidneys. The condition develops gradually as bacteria multiply in the kidney tissue.

  • Urinary Tract Infection (UTI)

    An infection that affects any part of the urinary system, most commonly occurring in the bladder and urethra. The infection begins when bacteria enter the urinary tract through the urethra and multiply in the bladder. UTIs can affect both the lower and upper urinary tract. The infection may be limited to the bladder or can spread to other parts of the urinary system.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-506589-30-00Protocol codeVAC52416BAC3001Estimated enrolment19 800 patientsSponsorJanssen Vaccines & Prevention B.V.

sourced from the EU Clinical Trials Register and site verification

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