RSV Prophylaxis — Monthly Monoclonal Antibody (High-Risk Infants) Pregnancy: Paediatric use only.

Palivizumab

Brand names: Synagis

Adult dose

Dose: Not applicable — paediatric use only

Route: N/A

Frequency: N/A

Max: N/A

Paediatric use only.

Paediatric dose

Dose: 15 mg/kg IM once monthly during RSV season (typically 5 doses: October/November to February/March) mg/kg

Route: Intramuscular

Frequency: Monthly (maximum 5 doses per RSV season)

Max: 15 mg/kg per dose

High-risk infants: premature birth ≤35 weeks GA (under 6 months at start of season), congenital heart disease (haemodynamically significant), chronic lung disease (bronchopulmonary dysplasia — on oxygen or diuretics). MHRA approved from 1992. Note: where nirsevimab is available, palivizumab is being phased out for most indications. Source: BNF for Children 2024; NICE TA284.

Dose adjustments

Renal

No dose adjustment — weight-based dosing.

Hepatic

No dose adjustment required.

Paediatric weight-based calculator

Patient weight (kg)

Clinical pearls

IMPACT trial (NEJM 1998): palivizumab reduced RSV hospitalisation by 55% in premature infants (≤35 weeks GA) and by 45% in infants with BPD vs placebo — established the monthly injection programme. Considered standard of care for high-risk infants for 25+ years.
Being superseded by nirsevimab: in healthcare systems where nirsevimab is available, palivizumab is now reserved for extreme cases where nirsevimab is not tolerated or available, or where a second dose of RSV prophylaxis is required in the same season (palivizumab can be re-dosed monthly, nirsevimab is not currently approved for repeat dosing within a season).
Haemodynamically significant CHD: palivizumab was the first drug licensed for RSV prophylaxis in CHD infants (post-CARDIAC trial). In complex CHD with pulmonary hypertension or cyanotic disease, RSV can cause life-threatening LRTIs. Palivizumab/nirsevimab reduces hospitalisation and ICU admissions.
Monthly scheduling challenge: five monthly IM injections requires coordinated hospital/community outreach visits — logistical burden on families, particularly if infant is otherwise well but premature. Nirsevimab's single-dose advantage is therefore clinically and programmatically significant.
Cost-effectiveness: palivizumab is expensive at £600–800 per injection (×5 = £3,000–4,000 per season). Nirsevimab at single-dose cost is more cost-effective for population-level use. NICE TA284 recommends palivizumab only for defined high-risk groups (TA284 still in effect for settings without nirsevimab). Source: BNF for Children 2024; Feltes et al. J Pediatr 2003; NICE TA284; MHRA SPC Synagis.

Contraindications

Hypersensitivity to palivizumab or humanised monoclonal antibodies
Active RSV infection (prophylaxis, not treatment)

Side effects

Fever, injection site reactions (most common)
Rhinitis, rash
Otitis media (may occur despite prophylaxis — RSV prophylaxis does not prevent all viral LRTI)

Interactions

Live vaccines: no interaction — palivizumab is a passive immunisation agent and does not interfere with active vaccination immune responses
Nirsevimab: do not co-administer

Monitoring

Observe for 30 minutes post-injection (anaphylaxis)
Weight monthly (dose recalculation at each visit)
RSV PCR if LRTI develops (confirm RSV despite prophylaxis — document for surveillance)

Reference: BNF for Children 2024; Simoes et al. NEJM 1998 (IMPACT trial); NICE TA284; MHRA SPC Synagis. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways