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Study of 20-valent pneumococcal conjugate vaccine (PCV20) booster response in healthy adults aged 78-84 years

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What is this trial about?

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

This clinical trial aims to study immune responses to Prevenar 20, a vaccine that helps prevent pneumococcal infection. The vaccine contains 20 different types of pneumococcal bacteria and is given as an injection into the muscle. The study focuses on healthy adults between 78 and 84 years old who previously received a different pneumococcal vaccine called PPSV23 in 2020.

The study will evaluate how well the immune system responds to Prevenar 20 when given as a booster vaccination. Participants will receive a single 0.5 milliliter dose of the vaccine. Blood samples will be collected before vaccination, one month after, and eleven months after to measure the body's immune response to the vaccine.

The research will also examine immune responses in the mucous membranes, which are the body's natural protective barriers. These measurements will help determine how effectively the vaccine stimulates both general and localized immunity against pneumococcal bacteria, which can cause serious infections like pneumonia.

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 one dose of Prevenar 20 vaccine through an injection in your muscle

    This vaccine helps prevent pneumococcal infection

    The vaccine will be given as part of the National Immunization Program in 2025

  2. Step 2

    First blood sample and mucosal test

    A blood sample will be taken before the vaccination to measure antibody levels

    A sample of the fluid from the lining of your nose will also be collected

  3. Step 3

    One-month follow-up

    One month after vaccination, you will need to provide another blood sample

    A second sample of nose fluid will be collected

    These samples help measure how your body responded to the vaccine

  4. Step 4

    Eleven-month follow-up

    Eleven months after vaccination, you will need to provide a final blood sample

    A final nose fluid sample will be collected

    These samples help measure the long-term effects of the vaccine

  5. Step 5

    Study completion

    The study will end after the collection of the final samples

    Total participation time will be approximately one year

    The overall study is expected to conclude by December 31, 2026

Who can join the trial?

8 criteria

  • Be born between the years 1941 and 1947
  • Have previously participated in the VIVO study during 2020
  • Have received the PPSV23 vaccine (a pneumococcal vaccine that helps protect against bacterial infections) in 2020
  • Be willing to receive the PCV20 vaccine (a new type of pneumococcal vaccine) as part of the National Immunization Program in 2025
  • Sign and provide informed consent form, which shows you agree to participate in the study
  • Be able to understand the purpose and requirements of the study, as determined by the research team
  • Can be either male or female
  • Must be capable of making independent decisions (not from vulnerable populations)

Who cannot join the trial?

11 criteria

  • History of severe allergic reactions to any pneumococcal vaccine or its components
  • Currently participating in another clinical trial or received another vaccine within 30 days
  • Pregnant or breastfeeding women
  • Active infection or fever above 38°C (100.4°F) at time of vaccination
  • Taking medications that suppress the immune system (immunosuppressive drugs)
  • History of serious chronic medical conditions affecting the immune system
  • Received blood products or immunoglobulins (antibody treatments) within the last 3 months
  • Previous vaccination with any pneumococcal vaccine within the past 5 years
  • Known bleeding disorders or current use of blood-thinning medications
  • History of Guillain-Barré syndrome (a rare disorder where the immune system attacks the nerves)
  • Any condition that, in the opinion of the study doctor, could interfere with the study evaluation
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Investigated drugs

PCV20 (Pneumococcal 20-valent Conjugate Vaccine) is a vaccine that helps protect against 20 different types of pneumococcal bacteria. This vaccine works by stimulating the immune system to produce antibodies that can fight against pneumococcal infections. It is specifically designed to provide protection against pneumonia and other serious infections caused by Streptococcus pneumoniae bacteria. The vaccine is particularly important for older adults who may be more vulnerable to pneumococcal infections due to their age.

What is already known about the treatment

PCV20 (Prevnar 20) - A preventive vaccine administered through intramuscular injection, designed to protect against 20 different strains of Streptococcus pneumoniae bacteria that can cause serious infections. This advanced pneumococcal conjugate vaccine works by stimulating the immune system to produce antibodies against pneumococcal bacteria, helping to prevent conditions like pneumonia, meningitis, and bloodstream infections. Approved by major health authorities worldwide, PCV20 belongs to the class of conjugate vaccines where bacterial sugars (polysaccharides) are linked to a carrier protein to enhance immune response, making it particularly effective for older adults who may have weakened immune systems.

Investigated diseases

Pneumococcal Infection - A bacterial infection caused by Streptococcus pneumoniae that can affect various parts of the body. The bacteria can spread through close contact with infected people, particularly through respiratory droplets. Pneumococcal infection can develop in different forms, including pneumonia (infection of the lungs), sinusitis (infection of the sinuses), or otitis media (middle ear infection). The bacteria can also enter the bloodstream or affect the protective membranes covering the brain and spinal cord. In healthy adults, the immune system usually provides some natural defense against these bacteria, though the level of protection varies among individuals.
Trial detailsLast updated 2 Oct 2026
Age65+ yearsPhasePhase IIITrial ID2025-521616-19-00Protocol codeIIV-720Estimated enrolment120 patientsSponsorRijksinstituut voor Volksgezondheid en Milieu (RIVM)

sourced from the EU Clinical Trials Register and site verification

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