ACIP Evidence to Recommendations for Use of Clesrovimab in Infants Age <8 months Born During or Entering Their First RSV season

About

The Evidence to Recommendations (EtR) Framework describes information considered in moving from evidence to ACIP recommendations.

Summary

Questions: Should clesrovimab be recommended for all infants <8 months of age born during or entering their first RSV season?

Population: All infants <8 months of age born during or entering their first RSV season

Intervention: Clesrovimab

Comparison: No immunization

Outcomes:

  • Medically attended RSV-associated lower respiratory tract infection (LRTI)
  • RSV-associated LRTI with hospitalization
  • RSV-associated LRTI with intensive care unit admission
  • All-cause medically attended LRTI
  • All-cause LRTI with hospitalization
  • Serious adverse events

Background

Before the introduction of respiratory syncytial virus (RSV) immunizations in 2023, RSV was the leading cause of hospitalization among U.S. infants.1 The highest hospitalization rates are in the first months of life and risk declines with increasing age in infancy and during early childhood. RSV transmission has generally followed a consistent seasonal pattern, beginning earliest in Florida and the Southeast and later in other parts of the continental United States.2 RSV has generally peaked during December and January across most of the United States. The COVID-19 pandemic interrupted seasonal circulation of RSV and many other respiratory viruses, but RSV circulation appears be returning to typical winter seasonality.

Prior to the introduction of RSV immunizations, it has been estimated that, each year among U.S. children aged less than 5 years, RSV is associated with 100 – 300 deaths, 58,000 – 80,000 hospitalizations, and approximately 2,000,000 medical encounters.3-7

Nirsevimab (Beyfortus, Sanofi and AstraZeneca), a long-acting monoclonal antibody for prevention of RSV-associated lower respiratory tract infection (LRTI), was recommended by the Advisory Committee on Immunization Practices (ACIP) in August 2023; vaccination of pregnant women with RSV vaccine (Abrysvo, Pfizer) at 32–36 weeks gestation was recommended by ACIP in September 2023. ACIP recommended that all infants be protected against RSV-associated LRTI through one of these two options: 1) maternal RSV vaccination during pregnancy or 2) administration of a long-acting RSV monoclonal antibody (nirsevimab) to the infant. 8 Use of both products was not recommended for most infants.

On June 9, 2025, the U.S. Food and Drug Administration (FDA) approved the Biologics License Application for a single dose (105 mg) of clesrovimab for the prevention of RSV lower respiratory tract disease in neonates (newborns) and infants born during or entering their first RSV season.9 Following FDA's regulatory action, the Advisory Committee on Immunization Practices (ACIP) met on June 25, 2025, and voted to recommend clesrovimab for infants aged <8 months born during or entering their first RSV season who did not receive protection through maternal RSV vaccination.

Additional background information supporting the ACIP recommendation on the use of clesrovimab can be found in the relevant publication of the recommendation referenced on the ACIP website.

Public Health Problem

Criteria Work Group Judgements Evidence Additional Information
Is the problem of public health importance? Yes Prior to the introduction of RSV immunizations, each year among children less than 5 years of age in the United States, RSV led to approximately 2,000,000 medical encounters, 58,000 – 80,000 hospitalizations and 100 – 300 deaths.1-6
Most infants (68%) are infected in the first year of life and nearly all (97%) by age 2 years.8 In the absence of RSV immunizations, RSV has been the leading cause of hospitalizations in infants.7 Among young infants, 2-3% have been hospitalized for RSV.9,10,11 The highest rates occur in the first months of life, and risk declines with increasing age in early childhood.9,11 Among children who are hospitalized for RSV, 79% of children aged <2 years have no underlying medical conditions.9 Therefore, all infants are at risk for hospitalization.
Prior to the COVID-19 pandemic, RSV transmission followed a consistent seasonal pattern. The percentage of PCR test results positive for RSV, by MMWR week using data from the National Respiratory and Enteric Virus Surveillance System averaged for the 2009 through 2019 seasons, shows that the RSV season consistently peaked during December to February. However, the COVID-19 pandemic interrupted seasonal circulation of RSV along with many other respiratory viruses. Following over a year of limited RSV circulation, the US experienced an interseasonal RSV wave that peaked in early August 2021. The 2022-2023 RSV season also peaked early from October through November. The 2023-2024 RSV season was a bit earlier and peaked from November through December. The 2024-2025 RSV season indicates a possible return to pre-pandemic seasonality with a December through January peak.12

Benefits and Harms

Criteria Work Group Judgements Evidence Additional Information
How substantial are the desirable anticipated effects? Large The estimated efficacy for protection against RSV-associated medically-attended lower respiratory tract infection (LRTI) was 60.4% (95% confidence interval [CI]: 44.1%, 71.9%), against RSV-associated LRTI with hospitalization was 90.9% (95% CI: 76.2%, 96.5%), and against RSV LRTI with ICU admission was 100.0% (95% CI: 24.0%, 100.0%). The estimated efficacy against all-cause medically-attended LRTI was 13.1% (95% CI: -0.6%, 24.8%) and 49.0% (95% CI: 26.7%, 64.5%) against all-cause LRTI with hospitalization.1
If approved by FDA and recommended by CDC, there will be two approved2 and recommended3 long-acting monoclonal antibody products for prevention of severe RSV disease in infants. Multiple products with different binding sites are beneficial if resistance mutations develop to either product. Multiple manufacturers in the same market allow for the following:
  • If one product has insufficient supply in the United States, the other product reduces the risk of shortage4
  • Competitive pricing of products may be created by market competition
 The Work Group felt that the desirable anticipated effects were large.
How substantial are the undesirable anticipated effects? Minimal to small The relative risk of serious adverse events in infants receiving clesrovimab versus placebo was 0.93 (95% CI: 0.77%, 1.12%). In the certainty assessment, there was serious concern for imprecision as too few infants were included in the trial to capture rare events.1
Additional harms of clesrovimab not included in GRADE consist of solicited adverse events (AEs) recorded 1-5 days post immunization. Injection-site and systemic reactions were comparable between clesrovimab (29.9%) and placebo (30.9%) arms. Irritability and somnolence were the most commonly reported solicited AEs and these were mostly Grade 1 (mild) or Grade 2 (moderate) reactions. The proportion of participants with solicited AEs of Grade 3 (severe) were low (≤0.2%) in both groups. There were no Grade 4 (potentially life-threatening) solicited AEs in either group.5
Additionally, rates of fever were comparable between the clesrovimab (3.7%) and placebo (4.0%) arms 1-5 days post immunization as well.1
 The Work Group felt that the undesirable anticipated effects were minimal to small.
Do the desirable effects outweigh the undesirable effects? Favors intervention The Work Group felt that the desirable effects of clesrovimab outweigh the undesirable effects.
What is the overall certainty of this evidence for the critical outcomes? Moderate For the critical outcomes, the certainty of evidence was high for RSV-associated medically-attended LRTI and RSV-associated LRTI with hospitalization. Moreover, there was moderate certainty that clesrovimab is effective in preventing RSV-associated LRTI with ICU admission.
In relation to important outcomes, the certainty of evidence was high for all-cause LRTI with hospitalization. However, clesrovimab was found to be ineffective in preventing all cause medically-attended LRTI with moderate certainty. Furthermore, SAEs were balanced between the clesrovimab group and the placebo group with moderate certainty.
The overall certainty of the evidence was rated as moderate.

Values

Criteria Work Group Judgements Evidence Additional Information
Does the target population feel the desirable effects are large relative to the undesirable effects? Probably yes Trust in pediatrician’s recommendation and fear of RSV infection was associated with increased intent to receive RSV immunization products for their infant.2 Receiving information about monoclonal antibodies and passive immunization led to a positive impact (68%) on willingness to receive the immunization.3
Looking at recent uptake of nirsevimab (a currently approved and recommended long-acting monoclonal antibody for the prevention of severe RSV disease in infants) to gauge parental interest, as of February 2025, 50% of women 18-49 years old who have an infant <8 months reported receipt of nirsevimab for their infant.7
Furthermore, nirsevimab uptake may be higher in settings of increased access, as 71% of newborns received nirsevimab at a US birthing center when it was universally offered.8
 The Work Group felt that based on the data presented, parents or caregivers either probably or definitely believe that the desirable effects of clesrovimab are large relative to undesirable effects.
Is there important variability in how patients value the outcome? Probably not important uncertainty or variability In a study of 523 women who were actively pregnant or pregnant within the last 12 months, 38% of respondents believed that their baby would have no symptoms or mild symptoms if they were to get sick with RSV; 24% expressed uncertainty about the disease severity or treatability if their baby got sick with RSV. Despite being unsure or perceiving RSV risk to be low, respondents were worried their baby would need to be hospitalized if they got sick with RSV.1
Parents deferring RSV immunization were concerned about adverse events and wanted to wait until the product had been available for longer, wanted more time to decide, or trusted their own prevention measures against RSV. 2-6
 The Work Group felt either that there probably was not important variability or that there was not important variability in how parents or caregivers value the prevention of severe RSV disease.

Acceptability

Criteria Work Group Judgements Evidence Additional Information
Is the intervention acceptable to key stakeholders? Yes Attitudes towards nirsevimab likely can be a proxy for attitudes towards clesrovimab. In a survey of 200 U.S. pediatricians conducted in October 2024, 77% of pediatricians reported that their practice had ever offered nirsevimab. Additionally, the majority of pediatricians agreed or strongly agreed that nirsevimab is safe for infants and effective against severe RSV disease in infants. They also felt confident discussing and recommending nirsevimab as well as co-administering nirsevimab with 1 or more vaccines in a single visit.1
RSV prevention through long-acting, monoclonal antibodies has been endorsed or recommended by national organizations, including but not limited to:
  • The American Academy of Pediatrics2
  • The American Academy of Family Physicians3
  • The National Foundation for Infectious Diseases4
 The majority of the Work Group felt that clesrovimab is acceptable to key stakeholders and the minority felt that it was probably acceptable to key stakeholders.

Feasibility

Criteria Work Group Judgements Evidence Additional Information
Is the intervention feasible to implement? Yes Clesrovimab storage, handling, and administration is anticipated to be similar to other routine immunizations for children. Clesrovimab is anticipated to be administered as an intramuscular injection using a single-dose, prefilled syringe. Clesrovimab can be stored at refrigerator temperature (2°C-8°C) and may be kept at room temperature between 68°F to 77°F (20°C to 25°C) for a maximum of 48 hours. After removal from the refrigerator, it must be used within 48 hours or discarded. Dosage is 0.7mL for all infants born during or entering their first RSV season regardless of weight. Clesrovimab can be administered simultaneously with other vaccines.
The Vaccines for Children program is a federally funded program that provides immunizations at no cost to children who might not otherwise be immunized because of inability to pay.1 Clesrovimab will be the second monoclonal antibody to be included in the VFC program. Some factors that may impact implementation include the following:
  • Clesrovimab is a single dose regardless of weight
  • Stocking clesrovimab may be challenging for providers who also need to stock nirsevimab for high-risk children 8 through 19 months entering their second RSV season and would prefer to stock a single RSV monoclonal antibody

Turning to nirsevimab again for insight, in a 2024 survey on the frequency of main challenges pediatricians reported or anticipated when offering nirsevimab, the three most commonly reported challenges were:

  • Parent/caregiver concerns around nirsevimab safety
  • Challenges knowing maternal RSV vaccination status to determine infant eligibility
  • Financial burden in purchasing of nirsevimab2

In a series of CDC Learning Collaborative calls hosted by the Association for Immunization Managers on nirsevimab administration in birthing hospitals, common barriers included:

  • Determining maternal RSV vaccination status
  • Storage and handling
  • Billing
  • Cost of nirsevimab
  • Nirsevimab supply/shortages
  • Determining a newborn’s VFC eligibility
  • Documenting nirsevimab receipt and care coordination
  • VFC requirements can be difficult to implement, and enrollment is burdensome
 The majority of the Work Group felt that clesrovimab would be feasible to implement among all infants <8 months of age born during or entering their first RSV season. The minority felt that clesrovimab would probably be feasible to implement.

Resource Use

Criteria Work Group Judgements Evidence Additional Information
Is the intervention a reasonable and efficient allocation of resources? Yes Cost effectiveness modeling was conducted by the University of Michigan and CDC. The results modeled a base case scenario for an annual birth cohort in which 50% of all infants are immunized with clesrovimab. Compared with an annual birth cohort in which only palivizumab is used among eligible high-risk infants (with 75% uptake of palivizumab among eligible infants), the model estimated the following events to be averted:
  • 121,022 outpatient visits
  • 43,480 emergency department visits
  • 20,198 hospital admissions
  • 4,444 ICU admissions
  • 20 deaths
  • 3,413 quality adjusted life years gained1

Examining the incremental cost effectiveness ratios, or how much it costs the U.S. to prevent a single outcome, it is estimated to cost roughly:

  • $2,948 to prevent one outpatient visit
  • $8,207 to prevent one emergency department visit
  • $17,666 to prevent one hospital admission
  • $80,300 to prevent an ICU admission
  • $17,666,032 to prevent one death
  • $104,543 per quality adjusted life year gained1

A one-way sensitivity analysis showed that the variables that had the largest impact on cost per quality adjusted life year gained are:

  • The disease specific inpatient costs, which at a high estimate, led to clesrovimab being cost saving
  • The estimates of quality adjusted life years lost due to RSV, which at a low estimate, doubles the cost per quality adjusted life year saved
  • The cost of clesrovimab per dose1

Merck also conducted modeling on the cost effectiveness of clesrovimab. At a cost of $457 a dose, which is the cost that the University of Michigan and CDC model used, Merck found that clesrovimab cost $36,636 per quality-adjusted life year gained. Based on a technical review by CDC, key differences in these models that may lead to differences in the ICERs were the initial efficacy and the waning trajectories, costs of medical visits and hospitalizations, and the inclusion of adverse events.1,2

 The majority of the Work Group felt that clesrovimab use among all infants under 8 months of age born during or entering their first RSV season is a reasonable and efficient allocation of resources with an estimated cost of $458 on average ($365 VFC / $560 other) per dose. A minority felt that clesrovimab probably is a reasonable and efficient allocation of resources.

Equity

Criteria Work Group Judgements Evidence Additional Information
What would be the impact of the intervention on health equity? Probably increased Data on seasonal, population-based rates of RSV-associated hospitalization among U.S. infants less than 6 months during the 2018-2019 to 2024-2025 seasons from RSV-NET, indicate that there were differences in hospitalization rates among infants less than 6 months old by race and ethnicity, but these differences varied by season.1
Population-based rates of RSV-associated ICU admissions among U.S. infants less than 6 months old during the 2018-2019 to 2024-2025 seasons from RSV-NET, show that there were also differences in ICU admission rates among infants less than 6 months by race and ethnicity and these differences varied by season as well.1
A study found that RSV hospitalization rates were up to 7x higher among Alaska Native and American Indian children compared to other children aged less than 1 year.2 However, it is important to note that this study was limited to specific populations and might not be broadly representative of risk in all Alaska Native and American Indian children. National studies of death certificates found higher rates of RSV-associated death among non-Hispanic, Black and Hispanic children compared with non-Hispanic, White children.3 Hospitalization rates using New Vaccine Surveillance Network (NVSN) have shown mixed results.4 Several studies have shown no differences by race and ethnicity.5-8 Even when significant, relative risk for non-Hispanic, Black and Hispanic children mildly increased compared to non-Hispanic, White children (e.g., relative risk of 1.2-2.2).7-8
 The majority of the Work Group felt that clesrovimab would probably increase health equity. A minority felt that it probably would have no impact on health equity.

Work Group Interpretation Summary

The Work Group felt that the Phase 2b/3 trial of clesrovimab demonstrated high efficacy for prevention of severe RSV disease through 150 days. They noted that serious adverse events appeared balanced between the clesrovimab and placebo arms; however, they also noted that rare adverse events are unlikely to be detected in a trial of this size. Work Group discussion also highlighted that clesrovimab has demonstrated a shorter half-life than nirsevimab (421 vs 712 days); however, efficacy against severe RSV appeared to be sustained through 150 days. The Work Group also noted that clesrovimab and nirsevimab trial outcomes had different definitions, making direct comparisons in efficacy difficult.

The Work Group highlighted the benefits of multiple RSV antibody products and multiple manufacturers, including:

  • If RSV develops resistance to one product or one product has insufficient supply, another is available
  • Potential for decrease in price

The leading cause of hospitalization in infants (RSV) can be prevented through immunization. However, for RSV immunizations to have public health impact, they must be administered early:

  • For infants born outside the RSV season, high uptake prior to season onset is critical
  • For infants born during the RSV season, administration should be within the first week of life – ideally during the birth hospitalization
  1. Maas et al. https://www.sciensano.be/sites/default/files/pk_sna_and_efficacy_against_rsv_malri_from_a_phase_1b2a_study_of_the_monoclonal_antibody_clesrovimab_mk-1654_in_infants.pdf
  2. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/761328s000lbl.pdf

Balance of consequences

The Work Group felt that the desirable consequences clearly outweigh undesirable consequences in most settings.

Is there sufficient information to move forward with a recommendation? Yes

Policy options for ACIP consideration

  • ACIP does not recommend the intervention.
  • ACIP recommends the intervention for individuals based on shared clinical decision making.
  • ACIP recommends the intervention.

Draft recommendation (text)

Infants aged <8 months born during or entering their first RSV season who are not protected by maternal vaccination are recommended to receive one dose of clesrovimab.

On June 25, 2025, ACIP voted (5-2) in favor of recommendation.

Final deliberation and decision by ACIP

ACIP recommends the intervention.

References

Background

  1. Suh M, Movva N, Jiang X, Bylsma LC, Reichert H, Fryzek JP, et al. Respiratory Syncytial Virus Is the Leading Cause of United States Infant Hospitalizations, 2009-2019: A Study of the National (Nationwide) Inpatient Sample. J Infect Dis. 2022 Aug 15;226(Suppl 2):S154-S63.
  2. Hamid S, Winn A, Parikh R, Jones JM, McMorrow M, Prill MM, et al. Seasonality of Respiratory Syncytial Virus — United States, 2017–2023. MMWR Morb Mortal Wkly Rep. 2023;72:355–361. doi: 10.15585/mmwr.mm7214a1.
  3. Thompson WW, Shay DK, Weintraub E, Brammer L, Cox N, Anderson LJ, et al. Mortality Associated with Influenza and Respiratory Syncytial Virus in the United States. JAMA. 2003;289(2):179–186. doi:10.1001/jama.289.2.179
  4. Hansen CL, Chaves SS, Demont C, Viboud C. Mortality Associated with Influenza and Respiratory Syncytial Virus in the US, 1999-2018. JAMA Netw Open. 2022;5(2):e220527. doi:10.1001/jamanetworkopen.2022.0527
  5. Hall CB, Weinberg GA, Iwane MK, Blumkin AK, Edwards KM, Staat MA. The Burden of Respiratory Syncytial Virus Infection in Young Children. New England Journal of Medicine. 2009;360(6):588–98. doi: 10.1056/NEJMoa080487
  6. Rha B, Curns AT, Lively JY, Campbell AP, Englund JA, Boom JA, et al. Respiratory Syncytial Virus–Associated Hospitalizations Among Young Children: 2015–2016. Pediatrics. 2020;146(1):e20193611. doi: 10.1542/peds.2019-3611
  7. McLaughlin JM, Khan FL, Schmitt H-J, Agosti Y, Jodar L, Simões E, et al. Respiratory Syncytial Virus-Associated Hospitalization Rates among US Infants: A Systematic Review and Meta-Analysis. Open Forum Infectious Diseases. 2020;7(Supplement_1): S843. doi: 10.1093/ofid/ofaa439.1897
  8. Fleming-Dutra KE, Jones JM, Roper LE, et al. Use of the Pfizer Respiratory Syncytial Virus Vaccine During Pregnancy for the Prevention of Respiratory Syncytial Virus-Associated Lower Respiratory Tract Disease in Infants: Recommendations of the Advisory Committee on Immunization Practices-United States, 2023. MMWR Morb Mortal Wkly Rep 2023;72:1115-22. doi: 10.15585/mmwr.mm7241e1. PMID: 37824423; PMCID: PMC10578951.
  9. Merck. U.S. FDA Approves Merck's ENFLONSIA™ (clesrovimab-cfor) for Prevention of Respiratory Syncytial Virus (RSV) Lower Respiratory Tract Disease in Infants Born During or Entering Their First RSV Season. News Release. https://www.merck.com/news/u-s-fda-approves-mercks-enflonsia-clesrovimab-cfor-for-prevention-of-respiratory-syncytial-virus-rsv-lower-respiratory-tract-disease-in-infants-born-during-or-entering-their-fir/

Public Health Problem

  1. Hall CB, Weinberg GA, Iwane MK, Blumkin AK, Edwards KM, Staat MA. The Burden of Respiratory Syncytial Virus Infection in Young Children. New England Journal of Medicine. 2009;360(6):588–98. doi: 10.1056/NEJMoa080487
  2. McLaughlin JM, Khan FL, Schmitt H-J, Agosti Y, Jodar L, Simões E, et al. Respiratory Syncytial Virus-Associated Hospitalization Rates among US Infants: A Systematic Review and Meta-Analysis. Open Forum Infectious Diseases. 2020;7(Supplement_1): S843. doi: 10.1093/ofid/ofaa439.1897
  3. CDC RSV-NET, unpublished data
  4. Thompson WW, Shay DK, Weintraub E, Brammer L, Cox N, Anderson LJ, et al. Mortality Associated with Influenza and Respiratory Syncytial Virus in the United States. JAMA. 2003;289(2):179–186. doi:10.1001/jama.289.2.179
  5. Matias et al. (2014) Estimates of mortality attributable to influenza and RSV in the United States during 1997 - 2009 by influenza typeor subtype, age, cause of death and risk status. Influenza and Other Respiratory Viruses 8(5), 507-515.
  6. Hansen CL, Chaves SS, Demont C, Viboud C. Mortality Associated with Influenza and Respiratory Syncytial Virus in the US, 1999-2018. JAMA Netw Open. 2022;5(2):e220527. doi:10.1001/jamanetworkopen.2022.0527
  7. Glezen WP, Taber LH, Frank AL, Kasel JA. Risk of Primary Infection and Reinfection With Respiratory Syncytial Virus. Am J Dis Child. 1986;140(6):543–546. doi:10.1001/archpedi.1986.02140200053026
  8. Suh M, Movva N, Jiang X, Bylsma LC, Reichert H, Fryzek JP, et al. Respiratory Syncytial Virus Is the Leading Cause of United States Infant Hospitalizations, 2009-2019: A Study of the National (Nationwide) Inpatient Sample. J Infect Dis. 2022 Aug 15;226(Suppl 2):S154-S63.
  9. Hall CB, Weinberg GA, Blumkin AK, Edwards KM, Staat MA, Schultz AF, Poehling KA, Szilagyi PG, Griffin MR, Williams JV, Zhu Y, Grijalva CG, Prill MM, Iwane MK. Respiratory syncytial virus-associated hospitalizations among children less than 24 months of age. Pediatrics. 2013 Aug;132(2):e341-8. doi: 10.1542/peds.2013-0303. Epub 2013 Jul 22. PMID: 23878043.
  10. Langley, Gayle Fischer MD, MPH; Anderson, Larry J. MD. Epidemiology and Prevention of Respiratory Syncytial Virus Infections Among Infants and Young Children. The Pediatric Infectious Disease Journal 30(6):p 510-517, June 2011. | DOI: 10.1097/INF.0b013e3182184ae7
  11. CDC NVSN data
  12. CDC NREVSS data

Benefits and Harms

  1. Merck, 2024 personal communication, September 2024-Decmember 2024.
  2. Sinha A. Merck. Clesrovimab (MK-1654): Pediatric clinical Program. Presentation to ACIP on October 23, 2024. Atlanta, GA: US Department of Health and Human Services, CDC; 2024. https://www.cdc.gov/acip/downloads/slides-2024-10-23-24/02-RSV-Mat-Peds-Sinha-508.pdf; Merck, 2024 personal communication, September 2024-Decmember 2024; Food and Drug Administration. Center for Drug Evaluation and Research: Integrated review of clesrovimab application. Silver Spring, MD: US Department of Health and Human Services, Food and Drug Administration; 2025. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2025/761432Orig1s000IntegratedR.pdf
  3. FDA. Drugs@FDA: FDA-Approved Drugs. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/761328s000lbl.pdf
  4. Jones JM, Fleming-Dutra KE, Prill MM, et al. Use of Nirsevimab for the Prevention of Respiratory Syncytial Virus Disease Among Infants and Young Children: Recommendations of the Advisory Committee on Immunization Practices — United States, 2023. MMWR Morb Mortal Wkly Rep 2023;72:920–925. DOI: http://dx.doi.org/10.15585/mmwr.mm7234a4
  5. CDC. Emergency Preparedness and Response. Limited Availability of Nirsevimab in the United States – Interim CDC Recommendations to Protect infants from Respiratory Syncytial Virus (RSV) during the 2023-2024 Respiratory Virus Season. https://www.cdc.gov/han/2023/han00499.html
  6. FDA. Guidance for Industry. Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials. https://www.fda.gov/media/73679/download

Values

  1. CDC and University of Iowa/RAND survey, unpublished data
  2. Hinderstein S, Aragona E, Loyal J. Parent Perspectives on Nirsevimab for Their Newborn. Pediatrics. 2024 Dec 1;154(6):e2024067532. doi: 10.1542/peds.2024-067532. PMID: 39587878.
  3. Lee Mortensen G, Harrod-Lui K. Parental knowledge about respiratory syncytial virus (RSV) and attitudes to infant immunization with monoclonal antibodies. Expert Rev Vaccines. 2022 Oct;21(10):1523-1531. doi: 10.1080/14760584.2022.2108799. Epub 2022 Sep 5. PMID: 35929971.
  4. Wang Q, Yang L, Li L, Xiu S, Yang M, Wang X, Shen Y, Wang W, Lin L. Investigating parental perceptions of respiratory syncytial virus (RSV) and attitudes to RSV vaccine in Jiangsu, China: Insights from a cross-section study. Vaccine. 2025 Jan 12;44:126570. doi: 10.1016/j.vaccine.2024.126570. Epub 2024 Nov 29. PMID: 39612804.
  5. Matilde Zornoza Moreno, Jaime Jesús Pérez Martín, Mª Cruz Gómez Moreno & Mª Pilar Ros Abellán (2024) Parental knowledge on the respiratory syncytial virus before the nirsevimab immunization program: Attitudes toward immunization in an autonomous community of Spain, Human Vaccines & Immunotherapeutics, 20:1, 2357439, DOI: 10.1080/21645515.2024.2357439
  6. Ocana de Sentuary C, Testard C, Lagrée M, Leroy M, Gasnier L, Enes-Dias A, Leruste C, Diallo D, Génin M, Rakza T, Dubos F. Acceptance and safety of the RSV-preventive treatment of newborns with nirsevimab in the maternity department: a prospective longitudinal cohort study in France. EClinicalMedicine. 2024 Dec 9;79:102986. doi: 10.1016/j.eclinm.2024.102986. PMID: 39726670; PMCID: PMC11669793.
  7. CDC. RSVVaxView. Infant Protection Against Respiratory Syncytial Virus (RSV) by Maternal RSV Vaccination or Receipt of Nirsevimab, and Intent for Nirsevimab Receipt, United States. February 2025. https://www.cdc.gov/rsvvaxview/dashboard/nirsevimab-coverage-infants.html
  8. Puckett L, Kushner LE, Bio L, Cornell S, Wood M, Schwenk HT. Successful Implementation of Nirsevimab and Factors Influencing Uptake in Neonatal Care. Hosp Pediatr. 2025 Feb 1;15(2):99-107. doi: 10.1542/hpeds.2024-008070. PMID: 39568114.

Acceptability

  1. CDC. RSVVaxView. Pediatrician and OB/GYN Survey on RSV Immunization. November 14, 2024. https://www.cdc.gov/rsvvaxview/publications/rsv-immunization-survey-2024.html
  2. American Academy of Pediatrics. AAP Recommendations for the Prevention of RSV Disease in Infants and Children. July 8, 2025. https://publications.aap.org/redbook/resources/25379/AAP-Recommendations-for-the-Prevention-of-RSV?autologincheck=redirected
  3. AAFP. AAFP Endorses RSV Antibody for Infants and Young Children. August 11, 2023. https://www.aafp.org/news/health-of-the-public/rsv-antibody-aafp-approval.html
  4. National Foundation for Infectious Diseases. Updated Recommendations for Respiratory Season. July 2024. https://www.nfid.org/resource/contagious-chronicles-updated-recommendations-for-respiratory-season/

Feasibility

  1. CDC. Vaccines for Children Program. About the Vaccines for Children (VFC) Program. June 26, 2024. https://www.cdc.gov/vaccines-for-children/about/index.html
  2. CDC. RSVVaxView. Pediatrician and OB/GYN Survey on RSV Immunization. November 14, 2024. https://www.cdc.gov/rsvvaxview/publications/rsv-immunization-survey-2024.html

Resource Use

  1. Estimates provided by an updated UM-CDC model, where updates included VE and cost/dose. Original model and methods described here: Hutton DW, Prosser LA, Rose AM, Mercon K, Ortega-Sanchez IR, Leidner AJ, McMorrow ML, Fleming-Dutra KE, Prill MM, Pike J, Jones JM. Cost-Effectiveness of Nirsevimab for Respiratory Syncytial Virus in Infants and Young Children. Pediatrics. 2024 Dec 1;154(6):e2024066461. doi: 10.1542/peds.2024-066461. PMID: 39582316.
  2. Klodeta Kura, John C Lang, Dawei Wang, et al. Merck's technical report: Cost-effectiveness analysis of clesrovimab use in infants in the United States. (Version submitted to CDC and ACIP for review, January 27, 2025)

Equity

  1. CDC Respiratory Syncytial Virus (RSV) Hospitalization Surveillance Network (RSV-NET), unpublished data
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  4. CDC New Vaccine Surveillance Network (NVSN) data
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  8. Rha B, Curns AT, Lively JY, Campbell AP, Englund JA, Boom JA, Azimi PH, Weinberg GA, Staat MA, Selvarangan R, Halasa NB, McNeal MM, Klein EJ, Harrison CJ, Williams JV, Szilagyi PG, Singer MN, Sahni LC, Figueroa-Downing D, McDaniel D, Prill MM, Whitaker BL, Stewart LS, Schuster JE, Pahud BA, Weddle G, Avadhanula V, Munoz FM, Piedra PA, Payne DC, Langley G, Gerber SI. Respiratory Syncytial Virus-Associated Hospitalizations Among Young Children: 2015-2016. Pediatrics. 2020 Jul;146(1):e20193611. doi: 10.1542/peds.2019-3611. Epub 2020 Jun 16. PMID: 32546583.
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Content Source:
National Center for Immunization and Respiratory Diseases (NCIRD)