Seasonal influenza vaccination reduced the risk of related emergency department (ED) visits and hospitalizations among US children both with and without underlying medical conditions, though protection was somewhat lower in children with chronic conditions, suggests an analysis published in Pediatrics.
Led by researchers at Vanderbilt University Medical Center, the team analyzed data from 15,875 children aged 6 months to 17 years who presented to EDs or were admitted to hospitals across the United States during five flu seasons (2015 to 2020). Influenza was confirmed using molecular testing, and vaccination status was verified through immunization registries or health records.
Among the children included in the analysis, 2,821 (18%) tested positive for flu, and 40% of those with confirmed cases had at least one underlying medical condition, most commonly respiratory conditions such as asthma.
Vaccine effectiveness (VE) against flu-related ED visits or hospitalizations was 43% among children with underlying conditions, compared with 53% among children without underlying conditions.
Effectiveness varies by condition type
VE varied by type of condition. Protection was lowest among children with respiratory conditions, at 31%. Higher VE estimates were observed among children with endocrine conditions (64%) and neurologic or neuromuscular conditions (53%). For children with oncologic and/or immunosuppressive conditions, VE was 48%. But “all demonstrated significant protection,” write the authors, “suggesting that influenza vaccination remains broadly effective for all children.”
The team noted that, during the study, vaccine uptake appeared low in both kids with and without underlying conditions and that coverage is likely even lower now with the increase in vaccine hesitancy since the COVID-19 pandemic began.
“Given the increased risk for severe influenza complications in children with underlying conditions, it is crucial to identify strategies to improve vaccination uptake and investigate new approaches to vaccination in these populations,” write the authors.