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Study of GBS-NN/NN2 vaccine to prevent Group B streptococcus infection in healthy pregnant women: evaluating long-term immunity and booster dose safety during subsequent pregnancy

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This clinical trial focuses on a vaccine designed to prevent Group B Streptococcus infection. The study examines a vaccine called GBS-NN/NN2, which is given as an injection into the muscle. The purpose is to evaluate how long the immune response lasts after vaccination in pregnant women and to assess the safety and effectiveness of giving an additional booster dose during a subsequent pregnancy.

The vaccine is administered as a solution for injection, with a maximum single dose of 50 micrograms. The study will track how the body maintains protective antibodies over time after the initial vaccination. For some participants who become pregnant again during the study period, a booster dose of the vaccine will be given to examine its effects.

The study will monitor both mothers and their newborns to understand how the vaccine's protection is passed from mother to baby. Researchers will collect blood samples from mothers at various points during pregnancy and after delivery, as well as from the umbilical cord and infants after birth. The study will also track the general health and development of both mothers and babies to ensure the vaccine's safety.

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 participation

    You will be enrolled in the trial as a follow-up participant if you previously received at least one dose of GBS-NN/NN2 vaccine in Trial MVX0004 or MVX0005.

    The trial focuses on monitoring the immune response to the vaccine that helps prevent Group B Streptococcus infection.

  2. Step 2

    Annual blood tests

    Your blood will be tested once a year to measure the levels of specific antibodies (IgG) against the vaccine components.

    These tests will continue throughout the trial period until 2029.

  3. Step 3

    Pregnancy monitoring - without booster

    If you become pregnant during the trial period and do not receive a booster dose:

    Blood samples will be collected at delivery to measure antibody levels.

    A cord blood sample will be collected from your baby at birth to measure antibody levels.

  4. Step 4

    Pregnancy monitoring - with booster

    If you become pregnant and receive a booster dose of the vaccine:

    Blood samples will be collected before vaccination, one month after vaccination, at delivery, and 6 months after delivery.

    You will need to report any injection site reactions or general health changes for 7 days after vaccination.

    Any unexpected health events will be monitored for 28 days after vaccination.

    Health monitoring will continue up to 6 months after delivery.

  5. Step 5

    Infant monitoring - with maternal booster

    If you received the booster dose, your infant will be monitored as follows:

    Cord blood collection at birth

    Blood samples at 1 month and 3 months of age

    Health checks including weight, length, and head measurements at birth

    Development checkup at 6 months of age

    Health monitoring will continue up to 6 months of age

Who can join the trial?

7 criteria

  • Must be a previous participant of Trial MVX0004 or MVX0005 and have received at least 1 dose of the GBS-NN/NN2 vaccine (a vaccine against Group B streptococcus infection)
  • Must be able to read, understand, and sign an informed consent (a document explaining the study details and patient rights)
  • Must be willing and able to attend all scheduled clinic visits and follow the study procedures
  • Must agree to give access to medical records related to the study and materials from previous trials MVX0004 or MVX0005
  • Must be available throughout the entire duration of the study and be reachable by phone
  • Must be female (male participants are not eligible for this study)
  • Must be of adult age (18 years or older)

Who cannot join the trial?

12 criteria

  • Female participants who are pregnant or breastfeeding
  • History of severe allergic reactions to vaccines or vaccine components
  • Active infection or fever (temperature above 38°C/100.4°F) at the time of vaccination
  • Participants who received any other vaccine within 30 days before the study
  • History of Group B streptococcus (a type of bacteria) infection
  • Current participation in another clinical trial
  • Any serious chronic medical condition that could interfere with the study
  • Use of medications that affect the immune system
  • History of serious adverse reactions to previous vaccinations
  • Individuals who are not able to comply with the study schedule
  • Blood disorders or conditions that increase risk of bleeding
  • Any condition that, in the opinion of the study doctor, makes participation unsafe
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Investigated drugs

GBS-NN/NN2 is a vaccine designed to protect against Group B Streptococcus (GBS) infection. It is being studied in pregnant women to understand how long the immune protection lasts after vaccination and how well it works when given as a booster shot during subsequent pregnancies. This vaccine aims to create antibodies that can help protect both the mother and baby from GBS infection.

What is already known about the treatment

GBS-NN/NN2 - An investigational vaccine administered through intramuscular injection, specifically designed for the prevention of Group B Streptococcus (GBS) infections. This vaccine is currently undergoing clinical trials to evaluate its effectiveness in pregnant women, with a focus on providing protection through antibody response against specific bacterial proteins (AlpCN, RibN, Alp1N, and Alp2 3N). The vaccine works by stimulating the immune system to produce protective antibodies that can help prevent GBS infections, particularly in the context of maternal-fetal transmission. As a prophylactic immunological agent, it represents a potential advancement in preventing GBS-related complications during pregnancy and early infancy.

Investigated diseases

Group B Streptococcal (GBS) Infection – A bacterial infection caused by Streptococcus agalactiae that can affect people of all ages but primarily impacts newborns during or shortly after birth. The bacteria can naturally live in the digestive and lower reproductive tracts without causing symptoms in adults. In newborns, the infection can develop in the first week of life (early-onset) or between one week and three months of age (late-onset). The bacteria can cause various types of infections including bloodstream infections, pneumonia, and meningitis. The infection can spread from mother to baby during pregnancy or during labor and delivery.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2024-516364-28-00Protocol codeMVX008Estimated enrolment137 patientsSponsorMinervax ApS

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