RSV Prophylaxis for a 3-Day-Old Newborn
For a 3-day-old newborn, nirsevimab is now the recommended first-line RSV prophylaxis agent for all infants under 8 months entering their first RSV season, having replaced palivizumab as the primary prevention strategy. 1
Current Standard of Care: Nirsevimab
All infants under 8 months of age born during or entering their first RSV season should receive nirsevimab as a single-dose monoclonal antibody injection, which has become the preferred agent over the older monthly palivizumab regimen 1
Nirsevimab demonstrates 79% efficacy in preventing medically attended RSV-associated lower respiratory tract infection and offers the significant advantage of single-dose protection throughout the entire RSV season 1
The single intramuscular injection should be administered shortly before or during RSV season (typically November through March in the Northern Hemisphere) 1
When Palivizumab Remains an Option
Palivizumab is now reserved for specific situations where nirsevimab may not be available or appropriate, administered at 15 mg/kg intramuscularly monthly throughout RSV season with a maximum of 5 doses 1
For infants born before 29 weeks, 0 days' gestation who are younger than 12 months at RSV season start, palivizumab remains an acceptable alternative if nirsevimab is unavailable 1, 2
Palivizumab dosing requires monthly injections every 28-30 days, as each dose provides approximately one month of protection 3
Alternative: Maternal Vaccination Strategy
Pregnant individuals may receive RSVpreF vaccine (Abrysvo) as a one-time dose at 32-36 weeks' gestation for prevention of RSV disease in infants under 6 months of age 1
However, either maternal vaccination OR infant nirsevimab is recommended—not both for most infants, as dual prophylaxis is not indicated 1
If the mother received RSV vaccination during pregnancy (32-36 weeks), the newborn typically does not require additional prophylaxis unless they have specific high-risk conditions 1
Critical Implementation Details
For a 3-day-old newborn currently hospitalized, the first dose should be given 48-72 hours before discharge or promptly after discharge 4
If RSV season has already started, administer the first dose as soon as possible to provide protection when exposure risk is highest 3
The timing should align with local RSV epidemiology, which typically runs November through March in most U.S. regions, though it may begin earlier or last longer in certain areas 5, 3
Essential Non-Pharmacologic Measures (All Infants)
Eliminate all tobacco smoke exposure in the infant's environment, as this is a modifiable risk factor that significantly increases RSV hospitalization risk 5, 1
Restrict the infant from daycare and crowds during RSV season when feasible, and avoid situations where exposure to infected individuals cannot be controlled 1, 4
Practice meticulous hand hygiene for all caregivers and family members 1, 4
Ensure influenza vaccination for all household contacts and the infant once they reach 6 months of age, plus all age-appropriate immunizations on schedule 1, 4
Common Pitfalls to Avoid
Do not withhold routine childhood immunizations, as neither nirsevimab nor palivizumab interferes with standard vaccine schedules 1, 2
Do not use palivizumab or nirsevimab for treatment of established RSV infection—these agents are prophylactic only and provide no therapeutic benefit once infection has occurred 2, 4
Do not administer both maternal RSV vaccine-derived protection and infant monoclonal antibody prophylaxis routinely, as this dual approach is not recommended for most infants 1
For palivizumab specifically, do not discontinue monthly dosing prematurely before the end of RSV season, even if the infant reaches 6 or 12 months of age mid-season 5