RSV prophylaxis: Palivizumab, nirsevimab, and more
Current prevention strategies include 2 injectables for infants and young children, namely palivizumab and nirsevimab.
RSV prophylaxis: Palivizumab, nirsevimab, and more | Image Credit: © John Doe - © John Doe - stock.adobe.com.
Respiratory syncytial virus (RSV) illness is an extremely common cause of hospitalization in children in the United States and globally. An estimated 90% of children will be infected by 2 years of age, leading to over 3 million hospitalizations annually worldwide.1 Therefore, effective prevention would greatly ease this burden on patients, their families, and health care systems. Current prevention strategies include 2 injectables for infants and young children, namely palivizumab (Synagis; Swedish Orphan Biovitrum) and nirsevimab (Beyfortus; Sanofi). Other vaccines, Abrysvo (Pfizer) and Arexvy (GSK), have been approved, both for older people, with Abrysvo having the additional indication for use in pregnant women. All of these therapies will be discussed in this article.
Both palivizumab and nirsevimab are RSV monoclonal antibodies to provide RSV prevention via passive immunity and are not vaccines. Palivizumab binds to the RSV envelope fusion protein (F protein), which blocks viral replication. Nirsevimab binds to the RSV prefusion F protein to also block viral replication but has a longer half-life than palivizumab. Both of these injectables have been shown to drastically reduce the RSV burden on patients and hospital systems.1,2 Both have been approved by the FDA for preterm infants; however, only nirsevimab is approved for all infants regardless of medical history through the first year of life.3 Non–peer-reviewed industry data suggest that nirsevimab and palivizumab have similar efficacy and safety.
Palivizumab is administered as monthly injections during RSV season, usually approved for a 5-month regimen. Patients who are born during the RSV season usually require fewer than 5 doses. This intramuscular injectable has the most benefit for high-risk infants with prematurity, chronic lung disease, or congenital heart disease.4 Palivizumab has been shown to significantly lessen the rate of RSV hospitalization and RSV pediatric intensive care unit admissions in high-risk patients.4-6 Patients can also receive this injectable during their second RSV season as well, depending on their condition. These indications, along with the drug’s cost ($5000 to $9000 per year), have sequestered this injectable to be used under specific circumstances.5 Common adverse effects may include fever and rash (Table 1).7,8
Nirsevimab (Beyfortus) is administered as a onetime intramuscular injection at the beginning of the patient’s first RSV season. One dose should provide protection for 5 months. In multiple randomized studies of healthy infants, it has been shown to lessen RSV-associated lower respiratory tract infections as well as hospitalizations for those conditions.9 During those hospitalizations patients were less likely to require pediatric intensive care unit admission or even supplemental oxygen. This injectable has been approved for all newborns and those under 1 year of age.3 Only those infants with increased risk for severe RSV infection (eg, those who have bronchopulmonary dysplasia or cystic fibrosis, are on oxygen support, are immunocompromised, or are American Indian or Alaska Native) are recommended to receive nirsevimab during their second RSV season. Nirsevimab is available at a lower cost than palivizumab at approximately $500/injection.10,11 Common adverse effects may include rash, fever, swelling, and injection site reactions.
Seventy-five percent of hospitalizations due to RSV occur in the first year of life and less than 20% occurred in the second year of life, making RSV prophylaxis after 2 years of age less critical.8 As such, the World Health Organization (WHO) does not currently recommend nirsevimab for anyone older than 2 years, as it has not been studied in this population.
Lastly, Abrysvo and Arexvy are RSV vaccines that are given to older people. Abrysvo is approved for all patients older than 75 years and those older than 60 years at increased risk for RSV (eg, those who have asthma, chronic obstructive pulmonary disease, and heart disease). Arexvy is approved for all people aged 60 and older.11-13 It is currently not used for pregnant women due to safety issues related to an increase in preterm births during a trial of the same antigen. Common adverse effects of vaccination include injection site pain, headache, fatigue, and muscle pain (Table 2).
Abrysvo can also be given to pregnant women.12 This intramuscular injection can be given between 32.0 and 36.6 weeks of gestation from September through January.3 The timing of this injection will transfer immunoglobulins to the fetus to offer protection for 6 months. Abrysvo has been shown to reduce hospitalization due to RSV by 68% 3 months after birth and 57% within 6 months of birth.10 If a mother receives this vaccine in the third trimester, the WHO does not recommend nirsevimab administration for that infant; the American Academy of Pediatrics has a similar recommendation provided the maternal vaccine was administered at least 14 days prior to birth. The WHO does not make any recommendations regarding palivizumab in infants after maternal vaccination.
In summary, both palivizumab and nirsevimab have shown efficacy in reducing the impact of RSV on young children. While palivizumab has been mainly used in high-risk infants, nirsevimab can be used in all newborns prior to RSV season as well as those with risk factors during their second RSV season. Abrysvo and Arexvy are currently preventive options for older people, with Abrysvo also given to pregnant individuals.
References:
1. Hammitt LL, Dagan R, Yuan Y, et al; MELODY Study Group. Nirsevimab for prevention of RSV in healthy late-preterm and term infants. N Engl J Med. 2022;386(9):837-846. doi:10.1056/NEJMoa2110275
2. Griffin MP, Yuan Y, Takas T, et al; Nirsevimab Study Group. Single-dose nirsevimab for prevention of RSV in preterm infants. N Engl J Med. 2020;383(5):415-425. doi:10.1056/NEJMoa1913556
3. Immunizations to protect infants. Centers for Disease Control and Prevention. August 30, 2024. Accessed February 10, 2025. https://www.cdc.gov/rsv/vaccines/protect-infants.html
4. Howard N, Pudim E 3rd. Evolving strategies for respiratory syncytial virus (RSV): a review article of preventive agents and vaccines for RSV. Ann Pharmacother. Published online January 2, 2025. doi:10.1177/10600280241302085
5. Anderson EJ, Carosone-Link P, Yogev R, Yi J, Simões EAF. Effectiveness of palivizumab in high-risk infants and children: a propensity score weighted regression analysis. Pediatr Infect Dis J. 2017;36(8):699-704. doi:10.1097/INF.0000000000001533
6. Synagis prices, coupons, copay cards & patient assistance. Drugs.com. Accessed February 10, 2025. https://www.drugs.com/price-guide/synagis
7. Synagis significantly reduced RSV hospitalizations and the severity of those hospitalizations in the highest-risk populations. Swedish Orphan Biovitrum. Accessed February 10, 2016. https://www.synagishcp.com/efficacy-safety
8. Lambert M. AAP issues updated guidance on palivizumab prophylaxis for RSV infection. Am Fam Physician. 2014;90(12):867-868.
9. Drysdale SB, Cathie K, Flamein F, et al; HARMONIE Study Group. Nirsevimab for prevention of hospitalizations due to RSV in infants. N Engl J Med. 2023;389(26):2425-2435. doi:10.1056/NEJMoa2309189
10. Caserta MT, O’Leary ST, Munoz FM, Ralston SL; Committee on Infectious Diseases. Palivizumab prophylaxis in infants and young children at increased risk of hospitalization for respiratory syncytial virus infection. Pediatrics. 2023;152(1):e2023061803. doi:10.1542/peds.2023-061803
11. Beyfortus may be available to your baby at no cost. Sanofi. Accessed February 10, 2025. https://www.beyfortus.com/about/cost-and-coverage
12. Kampmann B, Madhi SA, Munjal I, et al; MATISSE Study Group. Bivalent prefusion F vaccine in pregnancy to prevent RSV illness in infants. N Engl J Med. 2023;388(16):1451-1464. doi:10.1056/NEJMoa2216480
13. Arexvy. Prescribing information. GSK; 2025. Accessed February 10, 2025. https://gskpro.com/content/dam/global/hcpportal/en_US/Prescribing_Information/Arexvy/pdf/AREXVY.PDF
The Role of the Healthcare Provider Community in Increasing Public Awareness of RSV in All Infants
April 2nd 2022Scott Kober sits down with Dr. Joseph Domachowske, Professor of Pediatrics, Professor of Microbiology and Immunology, and Director of the Global Maternal-Child and Pediatric Health Program at the SUNY Upstate Medical University.
