RSV Vaccine for Respiratory Syncytial Virus

Recruiting at 87 trial locations

Overseen By Pfizer CT.gov Call Center

Age: Any Age

Sex: Any

Trial Phase: Phase 3

Sponsor: Pfizer

Disqualifiers: BMI over 40, Severe allergies, Pregnancy issues, others

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 1

Duration: 1 week

550 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests the safety and effectiveness of a second dose of the RSVpreF vaccine in pregnant women. It also examines the duration of immunity from a previous dose given during an earlier pregnancy. Ideal candidates for this trial are pregnant women expecting a single baby, who previously received the RSVpreF vaccine during pregnancy and had no major issues detected in a recent ultrasound. The trial includes different groups, with some receiving the vaccine and others a placebo (a non-active treatment for comparison). As a Phase 3 trial, this study represents the final step before FDA approval, offering participants a chance to contribute to a potentially groundbreaking treatment for RSV.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the study team or your doctor.

Is there any evidence suggesting that RSVpreF is likely to be safe for humans?

Research has shown that RSVpreF, a vaccine for respiratory syncytial virus (RSV), offers benefits but also presents some safety concerns. In a study involving individuals aged 60 and older, the vaccine effectively prevented illnesses caused by RSV. However, more than half of the safety reports for RSVpreF were classified as serious, including hospital stays and visits to doctors or clinics.

Although the vaccine has been tested in various groups, participants should be aware of potential risks. Consulting with healthcare providers is crucial to determine if joining this trial is appropriate. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

RSVpreF is unique because it directly targets the prefusion form of the RSV F protein, which plays a critical role in the virus's ability to infect cells. Unlike traditional treatments that mainly focus on symptom relief after infection, RSVpreF aims to prevent infection from occurring in the first place. Researchers are excited about this vaccine because it has the potential to offer long-lasting protection and reduce the severity of RSV outbreaks, a significant improvement over current options that primarily include supportive care and symptom management.

What evidence suggests that RSVpreF might be an effective treatment for RSV?

Research has shown that the RSVpreF vaccine, which participants in this trial may receive, works effectively against the respiratory syncytial virus (RSV). Studies have found it to be 92% effective in preventing emergency visits for serious RSV-related breathing problems. It is also 89% effective in stopping RSV-related lung issues that require hospital or emergency care in adults over 60. Additionally, the vaccine is 83% effective at preventing hospital stays due to RSV-related breathing illnesses. These findings suggest that RSVpreF can significantly reduce the severity and impact of RSV infections. ^{6 7 8 9 10}

Who Is on the Research Team?

Pfizer CT.gov Call Center

Principal Investigator

Pfizer

Are You a Good Fit for This Trial?

This trial is for pregnant women aged 18 to 49, between 24 and 36 weeks along with a single baby and no known risks for complications. They must have received the RSVpreF or Abrysvo vaccine in a past pregnancy, had an ultrasound at 18+ weeks showing no major fetal issues, be deemed suitable by a doctor, consent to their baby's participation, and agree to study conditions.

Inclusion Criteria

Able to sign a consent form agreeing to follow the rules and requirements of the study

Had the RSVpreF or Abrysvo vaccine during a previous pregnancy

Had an ultrasound scan at 18 weeks or later during their current pregnancy with no major fetal problems detected

Exclusion Criteria

History of a severe bad reaction to a vaccine or a serious allergic reaction (like anaphylaxis) to any ingredient in the study vaccine or a similar vaccine

Current pregnancy problems or issues at the time of giving consent

Previous pregnancy issues or problems at the time of giving consent

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Pregnant participants receive a second dose of RSVpreF or placebo, and non-pregnant participants have blood samples taken

1 week

1 visit (in-person)

Follow-up

Infants are monitored for safety and antibody levels for six months after birth

6 months

Multiple visits (in-person)

Long-term follow-up

Non-pregnant participants' immune response persistence is evaluated over time

Long-term

What Are the Treatments Tested in This Trial?

Interventions

• RSVpreF

Trial Overview The study tests the safety and effectiveness of administering a second dose of RSVpreF during subsequent pregnancies. It also measures how long immunity lasts from one dose given in a previous pregnancy by analyzing blood samples from nonpregnant participants who were previously vaccinated.

How Is the Trial Designed?

Group I: RSVpreF Experimental Treatment 1 Intervention

Group II: Placebo Placebo Group 1 Intervention

Who Is Running the Clinical Trial?

Pfizer

Lead Sponsor

Trials

4,712

Recruited

50,980,000+

Known For

Vaccine Innovations

Top Products

Viagra, Zoloft, Lipitor, Prevnar 13

Albert Bourla

Pfizer

Chief Executive Officer since 2019

PhD in Biotechnology of Reproduction, Aristotle University of Thessaloniki

Patrizia Cavazzoni

Pfizer

Chief Medical Officer

MD from McGill University

Published Research Related to This Trial

Pfizer's bivalent RSV vaccine, RSVpreF, has been approved in the USA for use in pregnant individuals to protect infants from respiratory syncytial virus (RSV) illness, as well as for individuals aged 60 and older to prevent lower respiratory tract disease caused by RSV.

The vaccine has also received approval in the EU for both indications and is currently under review for regulatory approval in Canada and Japan, highlighting its potential global impact in preventing RSV-related illnesses.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Respiratory Syncytial Virus Prefusion F Subunit Vaccine: First Approval of a Maternal Vaccine to Protect Infants. Syed, YY.[2023]

The investigational bivalent prefusion F vaccine (RSVpreF) was well tolerated in healthy adults aged 18-85, with mostly mild to moderate side effects, indicating a favorable safety profile.

RSVpreF elicited strong immune responses in older adults, significantly increasing serum-neutralizing antibodies against RSV, suggesting it could effectively protect this vulnerable population from RSV disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Phase 1/2 Randomized Study of the Immunogenicity, Safety, and Tolerability of a Respiratory Syncytial Virus Prefusion F Vaccine in Adults With Concomitant Inactivated Influenza Vaccine. Falsey, AR., Walsh, EE., Scott, DA., et al.[2022]

The Ad26.RSV.preF vaccine candidate showed good safety and immunogenicity in a study involving 12 adults and 36 RSV-seropositive children, with no serious adverse events reported and only mild to moderate reactions observed.

The vaccine significantly increased RSV neutralization titers in children and resulted in fewer RSV infections compared to the placebo group, indicating its potential effectiveness in preventing RSV.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Phase 1/2a Safety and Immunogenicity of an Adenovirus 26 Vector Respiratory Syncytial Virus (RSV) Vaccine Encoding Prefusion F in Adults 18-50 Years and RSV-Seropositive Children 12-24 Months. Stuart, ASV., Virta, M., Williams, K., et al.[2023]

The RSVpreF vaccine candidate was found to be safe and well-tolerated in older adults (ages 65-85), eliciting strong and lasting immune responses against the respiratory syncytial virus, regardless of the formulation used.

Adding the adjuvant CpG/Al(OH)3 did not enhance the immune response compared to the standard aluminum hydroxide adjuvant, and most side effects were mild, indicating that the vaccine is a promising option for protecting older adults from RSV.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Phase 1/2 Study of a Respiratory Syncytial Virus Prefusion F Vaccine With and Without Adjuvant in Healthy Older Adults. Baber, J., Arya, M., Moodley, Y., et al.[2023]

The bivalent RSVpreF vaccine was found to be safe and well-tolerated in a study of 618 adults aged 18-49, with mostly mild or moderate local and systemic reactions and no serious adverse events reported within 12 months post-vaccination.

The vaccine induced strong virus-neutralizing responses, with antibody levels significantly higher than those needed for protection in high-risk infants, suggesting its potential effectiveness for maternal immunization against RSV.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Randomized Phase 1/2 Study of a Respiratory Syncytial Virus Prefusion F Vaccine. Walsh, EE., Falsey, AR., Scott, DA., et al.[2022]

The RSVPreF3 vaccine candidate was found to be safe for use in 213 healthy pregnant women, with no significant adverse events related to the vaccine or placebo reported during the study.

The vaccine effectively increased RSV-specific neutralizing antibody levels in mothers and successfully transferred these antibodies to newborns, indicating strong immunogenicity and potential protection for infants against RSV.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety and Immunogenicity of an Investigational Respiratory Syncytial Virus Vaccine (RSVPreF3) in Mothers and Their Infants: A Phase 2 Randomized Trial. Bebia, Z., Reyes, O., Jeanfreau, R., et al.[2023]

The Ad26.RSV.preF vaccine, tested in a phase 1/2a study with 352 adults aged 60 and older, was found to be well tolerated, showing similar side effects across different regimens.

Combining Ad26.RSV.preF with RSV preF protein significantly enhanced humoral immune responses while maintaining cellular responses, suggesting this combination could be more effective in generating immunity against RSV.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety, Immunogenicity, and Regimen Selection of Ad26.RSV.preF-based Vaccine Combinations: A Randomized, Double-blind, Placebo-Controlled, Phase 1/2a Study. Comeaux, CA., Bart, S., Bastian, AR., et al.[2023]

In a phase 2b trial involving 406 pregnant women, the RSVpreF vaccine demonstrated effective neutralizing antibody responses against RSV, with significant transplacental transfer to infants, indicating potential protection for newborns.

The vaccine was generally safe, with most side effects being mild to moderate, and the incidence of adverse events in both mothers and infants was similar to those in the placebo group, suggesting no major safety concerns.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prefusion F Protein-Based Respiratory Syncytial Virus Immunization in Pregnancy. Simões, EAF., Center, KJ., Tita, ATN., et al.[2022]

Citations

1. academic.oup.com academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaf496/8293665

Estimated Vaccine Effectiveness for Respiratory Syncytial ... The RSVpreF vaccine was 92% effective against respiratory syncytial virus–related acute respiratory illness emergency department ...

2. jamanetwork.com jamanetwork.com/journals/jamanetworkopen/fullarticle/2828028

Estimated Vaccine Effectiveness for Respiratory Syncytial ... In our primary analysis, RSVpreF effectiveness was 89% against RSV-related LRTD requiring hospitalization or ED visit among adults aged 60 years ...

3. jwatch.org jwatch.org/na59204/2025/10/08/rsvpref-vaccines-effects-severe-outcomes-rsv-infection

RSVpreF Vaccine's Effects on Severe Outcomes of RSV ... The vaccine was 83% effective at preventing hospitalization with RSV-associated respiratory disease and 16% effective against hospitalization ...

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11645642/

Estimated Vaccine Effectiveness for Respiratory Syncytial ... This case-control study estimates vaccine effectiveness of RSVpreF for RSV-related lower respiratory tract disease hospitalizations and emergency department ...

5. nature.com nature.com/articles/s41591-024-03431-7

Impact of RSVpreF vaccination on reducing the burden ... Prefusion F protein-based vaccines have shown high efficacy against RSV disease in clinical trials, offering promise for mitigating this burden.

6. cdc.gov cdc.gov/vaccine-safety/vaccines/rsv.html

Respiratory Syncytial Virus (RSV) Vaccine Safety RSV immunizations protect people at increased risk for severe RSV disease when used according to the approved guidelines and recommendations.

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11973799/

Safety surveillance of respiratory syncytial virus (RSV) ... Over half of the RSVpreF-linked reports, 54.6%, were deemed serious; among these, 47.5% led to hospitalisations, 25.4% to doctor or clinic ...

8. academic.oup.com academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaf061/8006665

Efficacy, Immunogenicity, and Safety of the Bivalent ... In this phase 3 trial in persons aged ≥60 years, RSVpreF demonstrated vaccine efficacy (VE) of 88.9% and 77.8% against RSV-associated LRTI with ≥3 symptoms at ...

9. nejm.org nejm.org/doi/full/10.1056/NEJMoa2213836

Efficacy and Safety of a Bivalent RSV Prefusion F Vaccine ... In an RSV challenge study involving healthy persons who were 18 to 50 years of age, the vaccine efficacy was 87% (95% confidence interval [CI], 54 to 96) ...

10. fda.gov fda.gov/media/168258/download

Review of Efficacy and Safety of Safety, immunogenicity, and preliminary efficacy results from this Phase 2 study supported the selection of RSVpreF 120 μg (without adjuvant) ...