Clinical Spectrum and Burden of Influenza-Associated Neurological Complications in Hospitalised Paediatric Patients

Abstract

BackgroundInfluenza is one of the most common causes of acute respiratory tract infections around the world. Influenza viruses can cause seasonal epidemics. There remains limited information on the impact of both seasonal influenza A and influenza B related hospitalisations from neurological complications in paediatric populations in Asia.ObjectivesTo examine both the clinical spectrum and healthcare burden of influenza-associated neurological complications (IANCs) within the paediatric population of Hong Kong.MethodsWe conducted a population-based retrospective study to identify all paediatric patients (<18 years) admitted to a public hospital in Hong Kong with a confirmed influenza A or B infection between 2014 and 2018 using the Clinical Data Analysis and Reporting System of the Hospital Authority. The clinical spectrum of the paediatric patients with IANCs was studied. The clinical burden of paediatric influenza patients with IANCs were compared to paediatric influenza patients without neurological complications.ResultsA total of 28,016 children admitted to the paediatric wards diagnosed to have influenza A or B infection were identified, accounting for 5.7% (28,016/489,955) of total paediatric admissions. 67.3% had influenza A and 32.7% had influenza B, and 8.9% had IANCs. The mean annual incidence of IANCs in children was 57 per 100,000 population. The spectrum of IANCs in our paediatric patients included febrile seizures (80.6%), myositis (11.4%), seizures with fever (5.4%), influenza-associated encephalitis/encephalopathy (IAE) (2.6%) and rarely Guillain–Barré syndrome (0.04%). Most paediatric patients with IANCs (85.5%) presented at a young age of <6 years. Paediatric patients with IANCs had significant longer hospital stays (p < 0.001), higher percentages of mechanical ventilation use (p < 0.05) and PICU admissions (p < 0.001), and higher mortality rates (p < 0.001) compared to those without neurological complications. Amongst those with IANCs, IAE was the sole cause of all seven reported mortalities.ConclusionsSeasonal influenza A & B is a common cause of hospitalisation for paediatric patients in Hong Kong. We found neurological complications from influenza A and B caused a significantly higher clinical burden compared to those without neurological complications. Children in younger age groups (<6 years old) are at highest risk and thus increasing vaccination coverage to this age group is recommended.

A Comparative Study of Severe and Critical Influenza B in Children in the 2021–2022 Winter Season

“…23 Several recently published articles have described extra-pulmonary complications in hospitalized children with influenza B prior to the COVID-19 pandemic. [24][25][26][27] Geerdes-Fenge et al treated 17 hospitalized children with influenza B in northern Germany in the winter season of 2017-2018, and revealed that 5 (29.4%) suffered extrapulmonary complications, 24 lower than 42% (37/88) found in the present study (Table 1). A few studies focusing on neurologic involvement in hospitalized children with influenza B observed that approximately 10-15% of the patients had neurologic complications.…”

“…Influenza can cause complications outside the respiratory system in both adults and children. [21][22][23][24][25][26][27] A large series study of 2330 hospitalized pediatric patients with influenza A (H1N1 pdm09) during the 2009-2010 pandemic in the USA revealed that 709 (30.4%) children had complications affecting the digestive, neurological, musculoskeletal and cardiovascular systems. 23 Several recently published articles have described extra-pulmonary complications in hospitalized children with influenza B prior to the COVID-19 pandemic.…”

“…A few studies focusing on neurologic involvement in hospitalized children with influenza B observed that approximately 10-15% of the patients had neurologic complications. [25][26][27] A study conducted in Hong Kong found that 7.3% of the children (672/9175) between 2014 and 2018 had neurologic complications. 25 Frankl et al reported that, during 2010-2017, 12.9% of the hospitalized children (53/412) in a tertiary pediatric hospital in the USA had neurologic complications.…”

“…[25][26][27] A study conducted in Hong Kong found that 7.3% of the children (672/9175) between 2014 and 2018 had neurologic complications. 25 Frankl et al reported that, during 2010-2017, 12.9% of the hospitalized children (53/412) in a tertiary pediatric hospital in the USA had neurologic complications. 26 Mattila et al showed that 16.1% of hospitalized patients (18/112) in a university hospital in Finland from 2004 to 2018 had neurological system involved.…”

Epidemiological and Clinical Characteristics of Influenza Outbreaks Among Children in Chongqing, China

“…Though generally considered as a mild disease, according to the latest estimate, 290,000-650,000 deaths due to influenza occur each year (2). Recent studies tend to focus on differences in symptoms between influenza strains (3,4). Still, several epidemiological characteristics between influenza A and B infections have been proven to be distinguishable (5).…”