Palivizumab

Palivizumab is a recombinant humanized monoclonal antibody with anti-RSV activity [see Microbiology ( 12.4 ) ].

• Synagis is indicated for the prevention of serious lower respiratory tract disease caused by respiratory syncytial virus (RSV) in pediatric patients: with a history of premature birth (less than or equal to 35 weeks gestational age) and who are 6 months of age or younger at the beginning of RSV season, with bronchopulmonary dysplasia (BPD) that required medical treatment within the previous 6 months and who are 24 months of age or younger at the beginning of RSV season, with hemodynamically significant congenital heart disease (CHD) and who are 24 months of age or younger at the beginning of RSV season [see Clinical Studies ( 14 ) ].

• Synagis is contraindicated in children who have had a previous significant hypersensitivity reaction to Synagis [see Warnings and Precautions ( 5.1 ) ]. Previous significant hypersensitivity reaction to Synagis.contraindicated

15 mg per kg of body weight, administered intramuscularly prior to commencement of the RSV season and remaining doses administered monthly throughout the RSV season. ( 2.1 ) Children undergoing cardio-pulmonary bypass should receive an additional dose of Synagis as soon as possible after the cardio-pulmonary bypass procedure (even if sooner than a month from the previous dose). Thereafter, doses should be administered monthly as scheduled. ( 2.1 , 12.3 ) 2.1 Dosing Information The recommended dose of Synagis is 15 mg per kg of body weight given monthly by intramuscular injection. The first dose of Synagis should be administered prior to commencement of the RSV season and the remaining doses should be administered monthly throughout the RSV season. Children who develop an RSV infection should continue to receive monthly doses throughout the RSV season. In the northern hemisphere, the RSV season typically commences in November and lasts through April, but it may begin earlier or persist later in certain communities. Synagis serum levels are decreased after cardio-pulmonary bypass [see Clinical Pharmacology ( 12.3 ) ]. Children undergoing cardio-pulmonary bypass should receive an additional dose of Synagis as soon as possible after the cardio-pulmonary bypass procedure (even if sooner than a month from the previous dose). Thereafter, doses should be administered monthly as scheduled. The efficacy of Synagis at doses less than 15 mg per kg, or of dosing less frequently than monthly throughout the RSV season, has not been established.

Anaphylaxis and anaphylactic shock (including fatal cases), and other severe acute hypersensitivity reactions have been reported. Permanently discontinue Synagis and administer appropriate medications if such reactions occur. ( 5.1 ) As with any intramuscular injection, Synagis should be given with caution to children with thrombocytopenia or any coagulation disorder. ( 5.2 ) Palivizumab may interfere with immunological-based RSV diagnostic tests such as some antigen detection-based assays. ( 5.3 , 12.4 ) 5.1 Hypersensitivity Reactions Cases of anaphylaxis and anaphylactic shock, including fatal cases, have been reported following initial exposure or re-exposure to Synagis. Other acute hypersensitivity reactions, which may be severe, have also been reported on initial exposure or re-exposure to Synagis. Signs and symptoms may include urticaria, pruritus, angioedema, dyspnea, respiratory failure, cyanosis, hypotonia, hypotension, and unresponsiveness. The relationship between these reactions and the development of antibodies to Synagis is unknown. If a significant hypersensitivity reaction occurs with Synagis, its use should be permanently discontinued. If anaphylaxis or other significant hypersensitivity reaction occurs, administer appropriate medications (e.g., epinephrine) and provide supportive care as required. If a mild hypersensitivity reaction occurs, clinical judgment should be used regarding cautious readministration of Synagis. 5.2 Coagulation Disorders Synagis is for intramuscular use only.

The most serious adverse reactions occurring with Synagis are anaphylaxis and other acute hypersensitivity reactions [see Warnings and Precautions ( 5.1 ) ]. Adverse reactions occurring greater than or equal to 10% and at least 1% more frequently than placebo are fever and rash. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact 1-866-773-5274 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Studies Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The data described below reflect exposure to Synagis (n=1639) compared with placebo (n=1143) in children 3 days to 24.1 months of age at high risk of RSV-related hospitalization in two clinical trials. Trial 1 was conducted during a single RSV season and studied a total of 1502 children less than or equal to 24 months of age with BPD or infants with premature birth (less than or equal to 35 weeks gestation) who were less than or equal to 6 months of age at study entry. Trial 2 was conducted over four consecutive seasons among a total of 1287 children less than or equal to 24 months of age with hemodynamically significant congenital heart disease. In Trials 1 and 2 combined, fever and rash were each reported more frequently among Synagis than placebo recipients, 27% versus 25%, and 12% versus 10%, respectively.

Safety and effectiveness in children older than 24 months of age at the start of dosing have not been established. ( 8.4 ) 8.1 Pregnancy Risk Summary Synagis is not indicated for use in females of reproductive potential. 8.2 Lactation Risk Summary Synagis is not indicated for use in females of reproductive potential. 8.4 Pediatric Use The safety and effectiveness of Synagis in children older than 24 months of age at the start of dosing have not been established [see Clinical Studies ( 14 ) ].

Metabolism

In children less than or equal to 24 months of age without congenital heart disease (CHD), the mean half-life of palivizumab was 20 days and monthly intramuscular doses of 15 mg per kg achieved mean ± SD 30 day trough serum drug concentrations of 37 ± 21 mcg per mL after the first injection, 57 ± 41 mcg per mL after the second injection, 68 ± 51 mcg per mL after the third injection, and 72 ± 50 mcg per mL after the fourth injection. Trough concentrations following the first and fourth Synagis dose were similar in children with CHD and in non-cardiac patients.

Overdoses with doses up to 85 mg per kg have been reported in clinical studies and post-marketing experience with Synagis, and in some cases, adverse reactions were reported. In case of overdosage, it is recommended that the patient be monitored for any signs or symptoms of adverse reactions and appropriate symptomatic treatment instituted.

• Jun 19, 1998BLABLA103770Swedish Orphan

Reference statistics from the openFDA drug-shortage dataset. For a live view, consult the FDA database directly. Not clinical guidance.

• Synagis, Injection, 100 mg/1 mL (NDC 66658-231-01)To be discontinued
  Sponsor: Swedish Orphan Biovitrum AB
  Updated Aug 13, 2025
• Synagis, Injection, 50 mg/.5 mL (NDC 66658-230-01)To be discontinued
  Sponsor: Swedish Orphan Biovitrum AB
  Updated Aug 13, 2025

1. 1Respiratory Syncytial Virus Infection2,08614%
2. 2Pyrexia1,4419.5%
3. 3Bronchiolitis1,2738.4%
4. 4Death1,0687.0%
5. 5Cough1,0246.7%
6. 6Pneumonia9466.2%
7. 7Dyspnoea7825.1%
8. 8Vomiting6554.3%
9. 9Nasopharyngitis6384.2%
10. 10Influenza5013.3%
11. 11Bronchitis4182.7%
12. 12Diarrhoea3972.6%
13. 13Off Label Use3972.6%
14. 14Product Dose Omission Issue3902.6%
15. 15Covid-193632.4%

Recent PubMed references pinned to Palivizumab as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Palivizumab prophylaxis and risk of RSV infection among moderate-to-late preterm infants: A nationwide Korean cohort study from 2018 to 2022.
  Medicine · 2026 · So H, Kim Y, Yoon Y, et al.
  PMID 42071832DOI 10.1097/MD.0000000000048498
• Meta-analysis of the efficacy of palivizumab versus nirsevimab at preventing medically attended respiratory syncytial virus infections in non-hospitalized preterm infants.
  Human vaccines & immunotherapeutics · 2026 · Fullarton J, Paes B, Waghorne N, et al.
  PMID 41919667DOI 10.1080/21645515.2026.2652679
• The Effectiveness of the Palivizumab Programme in Reducing the Risk of Paediatric Asthma: A Population-Based Study in Ontario, Canada.
  Paediatric and perinatal epidemiology · 2026 · Foley KA, Buchan SA, McNally D, et al.
  PMID 41914371DOI 10.1111/ppe.70141
• Cost-Effectiveness of Nirsevimab and Maternal RSVpreF Immunization Strategies in Low-Risk Infants.
  Pediatrics · 2026 · Tsung S, Zeng YB, Shah K, et al.
  PMID 41713490DOI 10.1542/peds.2025-071558
• The Effectiveness of Respiratory Syncytial Virus Prophylaxis Programme using Palivizumab in Preterm Infants: A single institute retrospective study.
  Sultan Qaboos University medical journal · 2026 · Al Mandhari H, Al Kendi S, Al-Balushi N, et al.
  PMID 41659222DOI 10.18295/2075-0528.2955
• Is Palivizumabe a Protective Factor for the Development of Asthma in Children? A Systematic Review With Metanalysis.
  Pediatric pulmonology · 2025 · Manini MB, da Silva NC, de Castro RA, et al.
  PMID 40844025DOI 10.1002/ppul.71242
• Cost of universal immunization with Nirsevimab vs. standard of practice for infants in their first RSV season. Foggia District, Italy, 2023-2024.
  Vaccine · 2025 · Fortunato F, Martinelli D, Ascatigno L, et al.
  PMID 40749347DOI 10.1016/j.vaccine.2025.127550
• Palivizumab for preventing severe respiratory syncytial virus (RSV) infection in children.
  The Cochrane database of systematic reviews · 2025 · Garegnani L, Roson Rodriguez P, Escobar Liquitay CM, et al.
  PMID 40698576DOI 10.1002/14651858.CD013757.pub3

The 10 most recently updated of 33 ClinicalTrials.gov registrations naming Palivizumab as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Clesrovimab (MK-1654) in Infants and Children at Increased Risk for Severe Respiratory Syncytial Virus (RSV) Disease (MK-1654-007)
  Completed · Phase 3 · Interventional · 1,003 enrolled · Merck Sharp & Dohme LLC
  NCT04938830updated 2026-05-08
• Study of Palivizumab in Children With High Risk of Severe Respiratory Syncytial Virus (RSV) Disease
  Recruiting · Interventional · 138 enrolled · AstraZeneca
  NCT06851806updated 2026-04-17
• Adenoviral Vector Monotherapy or Combination With Chemotherapy in Subjects With Recurrent/Metastatic Breast Cancer.
  Terminated · Phase 2 · Interventional · 12 enrolled · Alaunos Therapeutics
  NCT01703754updated 2025-08-28
• A PK Study Comparing MB05, EU-sourced Synagis® and US-sourced Synagis® in Healthy Volunteers.
  Completed · Phase 1 · Interventional · 150 enrolled · mAbxience Research S.L.
  NCT05121246updated 2025-04-02
• A Study to Evaluate the Safety of MEDI8897 for the Prevention of Medically Attended Respiratory Syncytial Virus(RSV) Lower Respiratory Track Infection (LRTI) in High-risk Children
  Completed · Phase 2 · Phase 3 · Interventional · 925 enrolled · AstraZeneca
  NCT03959488updated 2023-09-21
• Adherence to Palivizumab Prophylaxis
  Completed · Interventional · 229 enrolled · Kosuyolu Heart Hospital
  NCT05778240updated 2023-03-21
• Phase 1 Study to Evaluate the Safety and Immunogenicity of a Candidate Vaccine Against Respiratory Syncytial Virus
  Completed · Phase 1 · Interventional · 60 enrolled · Virometix
  NCT04519073updated 2022-03-07
• Exploratory Study to Estimate the Prophylactic Efficacy of Palivizumab in Healthy Adult Participants Inoculated With RSV
  Completed · Phase 1 · Interventional · 56 enrolled · mAbxience Research S.L.
  NCT04540627updated 2021-10-04
• Prospective Study for the Use of Palivizumab (Synagis®) in High-risk Children in Germany
  Completed · Observational · 30,804 enrolled · AbbVie (prior sponsor, Abbott)
  NCT01155193updated 2018-10-29
• Study to Assess the Immune Reactivity of the Liquid and Lyophilized Formulations of Palivizumab (MEDI-493, Synagis)
  Completed · Phase 4 · Interventional · 417 enrolled · MedImmune LLC
  NCT00233064updated 2018-06-27

Frequently asked questions

How does Palivizumab work?

Palivizumab is a recombinant humanized monoclonal antibody with anti-RSV activity [see Microbiology ( 12.4 ) ].

What is Palivizumab used for?

According to FDA labeling, Palivizumab carries indications including: Synagis is indicated for the prevention of serious lower respiratory tract disease caused by respiratory syncytial virus (RSV) in pediatric patients: with a history of premature birth (less than or equal to 35 weeks gestational age) and who are 6 months of age or younger at the beginning of RSV season, with bronchopulmonary dysplasia (BPD) that required medical treatment within the previous 6 months and who are 24 months of age or younger at the beginning of RSV season, with hemodynamically significant congenital heart disease (CHD) and who are 24 months of age or younger at the beginning of RSV season [see Clinical Studies ( 14 ) ].. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Palivizumab?

Palivizumab is classified as Antiviral monoclonal antibodies, Respiratory Syncytial Virus Anti-F Protein Monoclonal Antibody, Fusion Protein Inhibitors, Decreased Cell Wall Synthesis & Repair.

What are the brand names for Palivizumab?

Palivizumab is marketed under brand names including Synagis.

What are the contraindications for Palivizumab?

Palivizumab labeling lists contraindications including: Synagis is contraindicated in children who have had a previous significant hypersensitivity reaction to Synagis [see Warnings and Precautions ( 5.1 ) ]. Previous significant hypersensitivity reaction to Synagis.. Always consult the full prescribing information and a clinician.