Landmark Approval Aims to Shield Infants from RSV at Birth
On August 21, 2023, the U.S. Food and Drug Administration (FDA) approved Abrysvo, the first-ever respiratory syncytial virus (RSV) vaccine designed for use in pregnant individuals, marking a major breakthrough in neonatal and maternal healthcare. Administered between 32 and 36 weeks of gestation, the vaccine provides passive immunity to newborns—protecting them from RSV-associated lower respiratory tract disease from birth through their first six months of life.
This approval represents a critical step forward in the prevention of a virus that is a leading cause of hospitalization in infants, particularly during their first year. The decision follows promising results from clinical trials that demonstrated significant efficacy and safety for both the mother and developing infant.
Why RSV Prevention Matters for Infants
RSV is a common and highly contagious virus that typically causes cold-like symptoms in older children and adults but can lead to serious respiratory illness in infants, especially those under 6 months. The virus is responsible for approximately:
- 58,000 to 80,000 hospitalizations annually among children under five in the U.S.
- A significant number of cases of bronchiolitis and pneumonia in newborns and infants.
- Increased risk in premature infants, babies with chronic lung or heart disease, and infants with weakened immune systems.
Until now, preventive options for RSV in infants were limited, with monoclonal antibody treatments like palivizumab (Synagis) available only for high-risk groups and requiring multiple doses. The approval of Abrysvo offers a broader, proactive approach by transferring maternal antibodies through the placenta, helping shield newborns at birth during their most vulnerable months.
How the Vaccine Works
Developed by Pfizer, Abrysvo is a bivalent recombinant RSV prefusion F protein vaccine—engineered to trigger an immune response against both RSV-A and RSV-B subtypes. When administered to pregnant individuals between 32 and 36 weeks of gestation, the vaccine allows the mother to produce protective antibodies, which are then passed to the fetus in utero.
In a Phase 3 clinical trial involving more than 7,000 participants, the vaccine demonstrated:
- 82% efficacy in preventing severe RSV-related lower respiratory tract illness in infants within the first 90 days after birth.
- 69% efficacy in preventing medically attended RSV illness through the first six months.
No significant safety concerns were identified for either the mothers or their babies during or after pregnancy.
Public Health Implications
This FDA approval is part of a broader national effort to reduce RSV-related hospitalizations and complications in young children. It follows recent authorizations of RSV vaccines for older adults and the monoclonal antibody nirsevimab (Beyfortus) for infant RSV prevention.
The Centers for Disease Control and Prevention (CDC) is expected to issue official vaccination guidelines and recommendations for use later in 2023, with Abrysvo likely becoming available for use during the 2023–2024 RSV season.
Public health officials have praised the move as a game-changer for infant health and maternal immunization programs. Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, called the approval “a major advance in the protection of infants from a potentially life-threatening respiratory infection.”
Looking Ahead
With the FDA’s approval of Abrysvo for pregnant individuals, healthcare providers now have a powerful new tool to help reduce RSV-related illness and hospitalizations in the youngest and most at-risk members of the population. As RSV season approaches in the fall and winter, the vaccine will play a vital role in comprehensive maternal and infant care strategies.
Education efforts will be essential to ensure that expecting parents are aware of the new option and understand how maternal vaccination can safeguard their newborns from a virus that has long been a serious threat in pediatric care.
Source:
U.S. Food and Drug Administration – FDA Approves First RSV Vaccine for Use During Pregnancy
