On July 18th, 2023, the FDA approved Beyfortus (nirsevimab-alip) for the prevention of Respiratory Syncytial Virus (RSV) in neonates and infants born during or entering their first RSV season, and in children up to 24 months of age remaining vulnerable to RSV.
Background
RSV is a lower respiratory tract infection affecting infants, young children, and older adults.
According to the FDA 58,000-80,000 children younger than 5 years old are hospitalized due to RSV. Premature infants, infants 2 years or younger, and immunocompromised children are at higher risk of severe illness from RSV.
Symptoms of RSV include but are not limited to runny nose, decreased appetite and liquid consumption, cough with or without wheezing or difficulty breathing, irritability, decreased activity, and apnea. If any of these symptoms are seen or worsening contact your healthcare provider or seek medical attention. The spread of RSV can be limited by washing your hands often, avoiding touching your face with unwashed hands, avoiding contact with sick people and unclean surfaces, cleaning frequently touched surfaces, covering your mouth when coughing and sneezing, and staying home if you are not feeling well.
Beyfortus is a monoclonal antibody aimed at providing long-acting passive immunity by targeting the perfusion conformation of the RSV F protein. By blocking the conformational changes in the F protein it inhibits the fusion of the viral and cellular membrane and viral entry. Due to the long half life, one dose of Beyfortus is able to cover the whole RSV season.
Safety and Efficacy
Based on Clinical trials Trial 3, MELODY, and MEDLEY, Beyfortus was shown to be safe and efficacious compared to placebo. The risk of RSV was lowered by 70%-75% in the clinical trials mentioned. Safety and efficacy are similar to the current standard of care Synargis (palivizumab). The most common side effects of Beyfortus include rash and injection site reaction. The main attraction of Beyfortus is one dose can cover the duration of RSV season, while Synargis must be administered monthly throughout the RSV season for the same efficacy.
Talk to your healthcare provider to see if your child meets the criteria for Beyfortus.
Jason P Wong, PharmD Candidate 2024
