031 - Incidence of Influenza-Associated Serious Neurologic Events in Young Children

Publication Number: 31.5134

Brooke P.. Quertermous, Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, TN, United States; Derek Williams, VUMC, nashville, TN, United States; Jean Bruce, Vanderbilt University Medical Center, Nashville, TN, United States; Mert Sekmen, Vanderbilt University School of Medicine, Nashville, TN, United States; Yuwei Zhu, Vanderbilt University Medical Center, NASHVILLE, TN, United States; Carlos Grijalva, Vanderbilt University School of Medicine, Nashville, TN, United States; James W. Antoon, Vanderbilt University Medical Center, Nashville, TN, United States

Background: The American Academy of Pediatrics and the Infectious Diseases Society of America recognize children < 5 years of age and those with neurologic conditions to be at-risk for complications of influenza such as hospitalization and death. The incidence of serious influenza-associated neurologic events in U.S. children < 5 years of age is unknown.

Objective: The objective of this study was to determine the population-based incidence of influenza-associated serious neurologic events in children < 5 years of age.

Design/Methods: Children < 5 years with an outpatient ICD-10 diagnosis of influenza during the 2016/2017-2019/2020 influenza seasons were identified using the Tennessee Medicaid database. Serious influenza-associated neurologic events were defined as a neurologic event resulting in hospitalization. Follow-up for outcome ascertainment began on the date of the influenza diagnosis and continued for a total of 10 days unless one of the following occurred: end of influenza season, loss of enrollment, death, or occurrence of a qualifying serious neurologic event. The crude incidence of serious influenza-associated neurologic events was calculated by dividing the number of events by the total influenza person-time and expressed per 100,000 person-weeks of influenza. Estimates were stratified by age, sex, neurologic comorbidity, influenza season, and antiviral use.

Results: A total of 79,727 cases of influenza among 70,258 unique children < 5 years were included. 65% of children were 2 years of age or older, 48% were female, 2% had complex chronic conditions and 0.4% of the children had an underlying neurologic comorbidity; 63% of children received antiviral treatment. Demographic information is shown in Table 1. The overall incidence of serious influenza-associated neurologic events in children < 5 years of age was 40.6 (95% CI 29.8-54.2) per 100,000 person-weeks of influenza. Incidence rates were similar when stratified by age, sex and antiviral treatment (Figure 1). Incidence was ~100-fold higher in those with underlying neurologic conditions compared to those without.

Conclusion(s): We determined the incidence of serious influenza-associated neurologic events in children < 5 years and showed that the incidence is markedly increased in children with underlying neurologic conditions. These findings emphasize the importance of mitigating influenza through prevention and vaccination efforts to prevent serious influenza complications, especially among young children with an underlying neurologic comorbidity.

Table 1. Clinical Characteristics of the Study Population


Figure 1. Flow Diagram
Slide1.jpeg

Figure 2. Incidence of Influenza-Associated Neurologic Events
Forest plot of the incidence of influenza-associated serious neurologic events in children
<5 years of age. The dotted line indicates overall incidence rate.


Table 1. Clinical Characteristics of the Study Population


Figure 1. Flow Diagram
Slide1.jpeg

Figure 2. Incidence of Influenza-Associated Neurologic Events
Forest plot of the incidence of influenza-associated serious neurologic events in children
<5 years of age. The dotted line indicates overall incidence rate.