Safety of Nirsevimab for RSV in Infants with Heart or Lung Disease or Prematurity

Background Respiratory syncytial virus (RSV) is associated with substantial morbidity in the United States, especially among infants. Nirsevimab, an investigational long-acting monoclonal antibody, was evaluated as an immunoprophylactic strategy for infants in their first RSV season and for its potential impact on RSV-associated, medically attended lower respiratory tract illness (RSV-MALRTI) and associated costs. Methods A static decision-analytic model of the US birth cohort during its first RSV season was developed to estimate nirsevimab’s impact on RSV-related health events and costs; model inputs included US-specific costs and epidemiological data. Modelled RSV-related outcomes included primary care and emergency room visits, hospitalizations including intensive care unit admission and mechanical ventilations, and RSV-related mortality. Results Under current standard of care, RSV caused 529 915 RSV-MALRTIs and 47 281 hospitalizations annually, representing $1.2 billion (2021 US dollars [USD]) in costs. Universal immunization of all infants with nirsevimab is expected to reduce 290 174 RSV-MALRTI, 24 986 hospitalizations, and expenditures of $612 million 2021 USD. Conclusions An all-infant immunization strategy with nirsevimab could substantially reduce the health and economic burden for US infants during their first RSV season. While this reduction is driven by term infants, all infants, including palivizumab-eligible and preterm infants, would benefit from this strategy.

Section: Methodsmentioning

confidence: 99%

Expected Impact of Universal Immunization With Nirsevimab Against RSV-Related Outcomes and Costs Among All US Infants in Their First RSV Season: A Static Model

Kieffer

Beuvelet

Sardesai

et al. 2022

“…Currently, RSV candidates are advancing in clinical development showing safety and efficacy against RSV LRTIs in otherwise healthy, late preterm, and term infants [ 10 , 11 ]. Hence, current, nationally representative data are needed to support policy discussions.…”

mentioning

confidence: 99%

Respiratory Syncytial Virus Is the Leading Cause of United States Infant Hospitalizations, 2009–2019: A Study of the National (Nationwide) Inpatient Sample

Suh

Movva

Jiang

et al. 2022

Background This study describes leading causes of hospitalization, including respiratory syncytial virus (RSV), in United States infants (<1 year) from 2009 through 2019. Methods Within the National (Nationwide) Inpatient Sample (NIS) data, hospitalizations were determined by primary diagnosis using International Classification of Diseases, Ninth or Tenth Revision codes. RSV was defined as 079.6, 466.11, 480.1, B97.4, J12.1, J20.5, or J21.0. Bronchiolitis was defined as 466.19, J21.8, or J21.9. Leading causes overall and by sociodemographic variables were identified. The Kids’ Inpatient Database (KID) was used for confirmatory analyses. Results Acute bronchiolitis due to RSV (code 466.11 or J21.0) was the leading primary diagnosis, accounting for 9.6% (95% confidence interval [CI], 9.4%–9.9%) and 9.3% (95% CI, 9.0%–9.6%) of total infant hospitalizations from January 2009 through September 2015 and October 2015 through December 2019, respectively; it was the leading primary diagnosis in every year accounting for >10% of total infant hospitalizations from December through March, reaching >15% in January–February. From 2009 through 2011, acute bronchiolitis due to RSV was the leading primary diagnosis in every birth month. Acute bronchiolitis due to RSV was the leading cause among all races/ethnicities, except Asian/Pacific Islanders, and all insurance payer groups. KID analyses confirmed these results. Conclusions Acute bronchiolitis due to RSV is the leading cause of US infant hospitalizations.

“…In contrast, since 2003, annual influenza vaccination is recommended for all infants starting at 6 months of age [ 5 , 6 ]. Development of new immunization strategies for RSV offer hope to prevent RSV illnesses and thus RSV mortality burden [ 27 , 28 ]; however, these strategies depend on timely and accurate data. Considering that infant mortality from RSV greatly exceeds that of influenza and full-term infants and those without comorbidities comprise the majority of RSV and bronchiolitis deaths, adoption of a similar RSV immunoprophylaxis program for all infants may be warranted to protect at-risk infants and also alleviate the mortality burden due to this disease.…”

Section: Discussionmentioning

confidence: 99%

Mortality Associated With Respiratory Syncytial Virus, Bronchiolitis, and Influenza Among Infants in the United States: A Birth Cohort Study From 1999 to 2018

Reichert

Suh

Jiang

et al. 2022

Background Infant mortality due to respiratory syncytial virus (RSV) in the United States is not well understood. Methods From 1999 to 2018, RSV, bronchiolitis, and influenza deaths were described for infants <1 year using linked birth/death datasets from the National Vital Statistics System. Mortality was described overall and by infant birth and death characteristics. Bronchiolitis was included as the plausible upper limit of RSV, while influenza served as a comparator. Results Total infant deaths were 561 RSV, 1603 bronchiolitis, and 504 influenza, and rates were 6.9 (95% confidence interval [CI], 6.4–7.5), 19.8 (95% CI, 18.9–20.8), and 6.2 (95% CI, 5.7–6.8) per 1 000 000 live births, respectively. The highest RSV rates were observed among <29 weeks’ gestational age infants (103.5; 95% CI, 81.8–129.1), American Indian/Alaskan Native (20.3; 95% CI, 11.6–33.0), and Medicaid-insured (7.3; 95% CI, 5.9–8.9). However, RSV mortality burden was greatest in full-term (53.7%), white (44.9%), and Medicaid-insured (61.7%) infants. Deaths outside the inpatient setting were 21% and 54% for RSV and bronchiolitis; more Medicaid- (58%) and other/unknown-insured (69%) infants with bronchiolitis died outside of the inpatient setting, compared to privately insured infants (48%) (P = .0327). Conclusions These national estimates emphasize the importance of considering all infants across all healthcare settings when describing RSV mortality.