Is it safe to administer Beyfortis (generic name) to a 4-day-old neonate?

Is it Safe to Give Beyfortis to a 4-Day-Old Newborn?

Yes, Beyfortus (nirsevimab-alip) is safe and FDA-approved for administration to newborns from birth, including a 4-day-old infant, for the prevention of RSV lower respiratory tract disease. 1

FDA-Approved Indication and Age Range

• Beyfortus is specifically indicated for neonates and infants born during or entering their first RSV season, with safety and effectiveness established from birth up to 12 months of age 1
• The FDA label explicitly states that use is "supported by evidence from adequate and well-controlled studies in neonates and infants from birth up to 12 months of age" 1
• Clinical trials (Trial 03 and Trial 04) included preterm infants (≥29 weeks gestational age) and term/late preterm infants (≥35 weeks gestational age) entering their first RSV season 1

Dosing for a 4-Day-Old Newborn

• For infants weighing less than 5 kg: administer a single 50 mg intramuscular (IM) dose 1
• For infants weighing ≥5 kg: administer a single 100 mg IM dose 1
• Most 4-day-old newborns will weigh less than 5 kg and should receive the 50 mg dose 1

Administration Guidelines

• Administer as a single intramuscular injection 1
• Monitor the infant for at least 60 minutes post-dose for any adverse reactions 1
• The injection should be given in the anterolateral aspect of the thigh 1

Safety Profile in Neonates

• The most common adverse reaction is rash, which occurred in clinical trials 1
• Hypersensitivity reactions have been reported in postmarketing surveillance, though they remain rare 1
• The safety profile in neonates from birth was consistent across all clinical trials, including those with chronic lung disease of prematurity and hemodynamically significant congenital heart disease 1

Critical Timing Consideration

• A 4-day-old infant is within the optimal window for RSV prophylaxis, as Beyfortus should be administered before or during the RSV season 1
• The single-dose regimen provides protection throughout the entire RSV season (approximately 5 months) 1

Common Pitfalls to Avoid

• Do not delay administration waiting for the infant to reach a certain age beyond birth—the medication is approved from day of birth 1
• Ensure correct weight-based dosing (50 mg for <5 kg, 100 mg for ≥5 kg) to avoid underdosing or overdosing 1
• Do not confuse Beyfortus with palivizumab (which requires monthly dosing)—Beyfortus is a single-dose prophylaxis 1
• Monitor for hypersensitivity reactions during the 60-minute post-administration observation period 1