NCT07768345 · Pfizer
A Study to Learn About Revaccination With a Vaccine Called RSVpreF in Immunocompromised Adults
What this study is about
The purpose of this phase 3 study is to learn the safety, tolerability and immunogenicity of revaccination with RSVpreF at approximately 1-, 2-, and 3-year intervals to inform the revaccination interval in immunocompromised adults. This study is seeking participants who are 18 years of age and older and will be grouped based on prior RSV vaccination history.
View original scientific description
The purpose of this phase 3 study is to learn the safety, tolerability and immunogenicity of revaccination with RSVpreF at approximately 1-, 2-, and 3-year intervals to inform the revaccination interval in immunocompromised adults. This study is seeking participants who are 18 years of age and older and will be grouped based on prior RSV vaccination history. Participants are required to be immunocompromised per study protocol. All participants in this study will receive 1 shot to their arm of a RSVPreF vaccine. Participants will take part in this study for about 12 months and will need to visit the clinical study site at least 4 times.
Interventions
BIOLOGICAL
RSVpreF Vaccine
RSVpreF Vaccine
Primary outcome measures
Percentage of participants reporting local reactions
Time frame: For up to 7 days after vaccination
Percentage of participants reporting systemic events
Time frame: For up to 7 days after vaccination
Percentage of participants reporting adverse events
Time frame: Through 1 month after vaccination
Percentage of participants reporting newly diagnosed chronic medical conditions
Time frame: Through 12 months after vaccination
Percentage of participants reporting serious adverse events
Time frame: Through 12 months after vaccination
Neutralizing Titers (NTs) for RSV A and RSV B expressed as Geometric Mean Titer (GMT)
Time frame: Before vaccination, 1 month, 6 months and 12 months after vaccination
NTs for RSV A and RSV B expressed as Geometric Mean Fold Rise (GMFR)
Time frame: Before vaccination, 1 month, 6 months and 12 months after vaccination
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Participants ≥18 years of age who are/were immunocompromised at the time of initial RSVpreF vaccination, per study protocol, and will be grouped based on prior RSV vaccination history:
- Group 1 will include participants naïve to any RSV vaccine.
- Group 2 will include participants who received a single prior dose of RSVpreF (Abrysvo) approximately 1 year (9 to 15 months) prior to enrollment.
- Group 3 will include participants who received a single prior dose of RSVpreF (Abrysvo) approximately 2 years (21 to 27 months) prior to enrollment.
- Group 4 will include participants who previously received 2 doses of RSVpreF in Study C3671023 Substudy B approximately 3 years (36 to 42 months) prior to enrollment.
- Participants should have a life expectancy ≥12 months (365 days) in the opinion of the investigator at enrollment. Key
Exclusion criteria
- Prior history of any subtype of Guillain-Barré Syndrome (GBS) of any etiology.
- History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any components of the study intervention(s).
- Participants with a history of transplant rejection, or PTLD, or participants who have had treatment for these conditions, within 90 days prior to study enrollment or suspected chronic humoral or cellular rejection.
- Receipt of B-cell depleting therapies within 180 days prior to initial study vaccination. Refer to the study contact for further eligibility details.
Where
- Los Angeles, California
- Washington D.C., District of Columbia
- Decatur, Georgia
- New York, New York
- Rochester, New York
- Durham, North Carolina
- Duncansville, Pennsylvania
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Sep 25, 2026 · Source of record for eligibility and locations