A Phase 3 interventional study of RSVpreF and Placebo in RSV Infection, sponsored by Pfizer. Recruiting at 97 sites in 4 countries. Open to participants aged 0 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by Pfizer · Phase 3, Interventional, and Prevention
Among 13 studies in Respiratory Syncytial Virus Infections by Pfizer — 2 open to participants now, 3 under way, 1 of them phase 3. Respiratory Syncytial Virus Infections · Pfizer.
Among the 13 studies in Respiratory Syncytial Virus Infections by Pfizer, this one has the largest planned enrollment of the 11 interventional ones that give a count, is one of 2 that started in 2025, is one of 2 in phase 3, and was the 12th registered.
306 studies on the registry are indexed under Respiratory Syncytial Virus Infections; 50 are open to participants now.
Browse Respiratory Syncytial Virus Infections studies →2 of the 13 studies in Respiratory Syncytial Virus Infections by Pfizer are open now, in 4 countries. Recruiting first, the newest first:
Pfizer
Ages 0 yrs–12 mo
By country, each count listing its studies:
Of the 30 Respiratory Syncytial Virus Infections studies recruiting now, 14 (47%) set no upper age limit and 12 (40%) stop at 75 or younger; 13 take children under 18; 9 take healthy volunteers.
This study: 0 Years and older · all sexes · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
13 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 6 · Phase 2 3 · Phase 3 3
First in 2017; this study’s year is marked. 2 started in 2025.
This study's planned enrollment of 550 is above the median of 89 across 223 interventional studies indexed under Respiratory Syncytial Virus Infections.
Median enrollment 16 across the 11 interventional studies, 551 across the 2 observational. Of the 9 that completed or were terminated, 4 (44%) have results posted.
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Pfizer is the lead sponsor of 3,337 studies on the registry; 150 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 392 (65%) have results posted.
2 of the studies in Respiratory Syncytial Virus Infections by Pfizer that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07235397PfizerEvaluating the Benefits of RSV Maternal Vaccination Using a Scottish National Dataset | 2026-11-13 |
| NCT06546800PfizerSPECIAL INVESTIGATION FOR ABRYSVO IN INDIVIDUALS AGED 60 YEARS OR OLDER | 2027-10-28 |
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Among the 13 studies in Respiratory Syncytial Virus Infections by Pfizer, from their registry updates:
Nothing recorded among them since 2026-09-25.
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This study aims to check how safe and well-tolerated a second dose of RSVpreF is when given during later pregnancies, and to see how long the immunity lasts from a single dose given during a previous pregnancy by examining the blood of nonpregnant participants who had the vaccine before.
This study will include pregnant participants and their unborn babies (Cohort 1 and Cohort 2) and non-pregnant participants (Cohort 3), as described below:
For both groups of pregnant participants, the study will look at how safe and well-tolerated the vaccine is during pregnancy, as well as how the body responds to it.
Infants will be monitored for six months after birth to check safety and antibodies level.
Pregnant Participants-Cohort 1 and Cohort 2 Key Inclusion Criteria
Key Exclusion Criteria
Infant Participants
Nonpregnant Participants-Cohort 3 Key Inclusion Criteria
Key Exclusion Criteria
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biological: RSVpreF
Biological: Placebo
Single Dose
Single Dose
Percentage of pregnant participants reporting local reactions
Pain at the injection site, redness, and swelling
Time frame: From Day 1 Through at least Day 7 after Vaccination
Percentage of pregnant participants reporting systemic events
Fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain, and joint pain
Time frame: From Day 1 Through at least Day 7 after Vaccination
Percentage of pregnant participants reporting adverse events
Time frame: From Day 1 through 4 weeks after vaccination
Percentage of pregnant participants reporting serious adverse events
Time frame: From Day 1 throughout the study
In infant participants born to pregnant participants receiving a second dose of the study intervention, the percentage of participants reporting adverse events.
Time frame: From birth through 1 month of age
In infant participants born to pregnant participants receiving a second dose of the study intervention, the percentage of participants reporting serious adverse events and newly diagnosed medical conditions.
Time frame: From birth through 6 months of age.
Proportion of participants achieving neutralizing antibody to RSV A and RSV B at birth
Time frame: At birth
Proportion of participants achieving neutralizing antibody to RSV A and RSV B at 3 months and 6 months
Time frame: At 3 months and 6 months
Plan to share: Yes — Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
Supporting information: Study protocol
Data sharing details ↗ · www.pfizer.com
Started Apr 2025 (actual). Primary completion is estimated for Feb 2028, 34 months after the start.
Of 27 industry-sponsored phase 3 interventional studies under Respiratory Syncytial Virus Infections, half reached primary completion within 8 months of starting (the median), counting those still running; a quarter within 4 and three quarters within 19. This study's planned 34 months is above that.
Counting every sponsor, half of 32 studies reached it within 8 months; a quarter within 6 and three quarters within 23.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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Studies of the drug tested here: Abrysvo
Respiratory Syncytial Virus Infections →