Nirsevimab Effectiveness Against Medically Attended Respiratory Syncytial Virus Illness and Hospitalization Among Alaska Native Children - Yukon-Kuskokwim Delta Region, Alaska, October 2023-June 2024
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Insights
Nirsevimab effectively prevents medically attended respiratory syncytial virus (RSV) illness and hospitalization in American Indian and Alaska Native infants and at-risk children. This monoclonal antibody offers significant protection for those in their first or second RSV season.
Area of Science:
- Pediatric Infectious Diseases
- Immunology
- Public Health
Background:
- Respiratory syncytial virus (RSV) is a major cause of pediatric hospitalizations.
- American Indian and Alaska Native (AI/AN) children face disproportionately high rates of RSV hospitalization.
- Nirsevimab, a monoclonal antibody, was recommended in August 2023 for infants and at-risk children to prevent severe RSV.
Purpose of the Study:
- To evaluate the effectiveness of nirsevimab in AI/AN children in Alaska.
- To assess nirsevimab's impact on medically attended RSV illness and hospitalization during the 2023-2024 season.
Main Methods:
- A retrospective evaluation was conducted in Alaska's Yukon-Kuskokwim Delta region.
- Effectiveness was estimated among 472 AI/AN children with medically attended acute respiratory illness (ARI).
- Participants were analyzed based on whether they received nirsevimab (≥7 days prior) and their RSV season (first or second).
Main Results:
- Overall, 48% of children with ARI had received nirsevimab.
- For children in their first RSV season (n=292), nirsevimab effectiveness was 76% against medically attended RSV illness and 89% against RSV hospitalization.
- For children in their second RSV season (n=180), effectiveness was 88% against medically attended RSV illness.
Conclusions:
- Nirsevimab demonstrates significant effectiveness in preventing medically attended RSV illness and hospitalization in AI/AN infants and at-risk children.
- The findings support nirsevimab's role in protecting vulnerable populations, including AI/AN children, against severe RSV outcomes.
- Nirsevimab is a valuable tool for preventing severe RSV in infants and children at increased risk, including those in their first or second RSV season.
Abstract:
Respiratory syncytial virus (RSV) is a leading cause of hospitalization among young children. Historically, American Indian and Alaska Native (AI/AN) children have experienced high rates of RSV-associated hospitalization. In August 2023, a preventive monoclonal antibody (nirsevimab) was recommended for all infants aged <8 months (born during or entering their first RSV season) and for children aged 8-19 months (entering their second RSV season) who have increased risk for severe RSV illness, including all AI/AN children. This evaluation in Alaska's Yukon-Kuskokwim Delta region estimated nirsevimab effectiveness among AI/AN children in their first or second RSV seasons during 2023-2024. Among 472 children with medically attended acute respiratory illness (ARI), 48% overall had received nirsevimab ≥7 days earlier (median = 91 days before the ARI-related visit). For children in their first RSV season (292), nirsevimab effectiveness was 76% (95% CI = 42%-90%) against medically attended RSV illness and 89% (95% CI = 32%-98%) against RSV hospitalization. For children in their second RSV season (180), effectiveness against medically attended RSV illness was 88% (95% CI = 48%-97%). Nirsevimab is effective for preventing severe RSV illness among infants entering their first RSV season and children entering their second season with increased risk for severe RSV, including all AI/AN children.
