Neurologic Complications in Children Hospitalized With Influenza Infections: Prevalence, Risk Factors and Impact on Disease Severity

Demographic and clinical characteristics of hospitalized children with suspected and laboratory-confirmed COVID-19 during the six waves of SARS-CoV-2 infection in northern Iran a retrospective cohort study

Introduction

Northern Iran is one of the regions of the country most affected by COVID-19. The aim of the current study was to examine the demographics, clinical characteristics, and outcomes of suspected and laboratory-confirmed patients <18 years of age hospitalized over two years (during six waves of SARS-CoV-2).

Methods

This retrospective cohort study examined hospitalized patients with suspected SARS-CoV-2 infection in Babol, northern Iran. The study included patients <18 years of age admitted to a pediatric referral hospital from March 7, 2020 to March 20, 2022. Epidemiological and demographic characteristics, real-time PCR cycle threshold (Ct), clinical data and COVID-19 results were analyzed in the hospitalized patients.

Results

Totally, 2,731 patients with suspected COVID-19 were examined from March 2020 to 2022, with a mean age of 4.6 years, and were male (54.3%). Most suspected cases occurred during the fifth (Delta) and sixth (Omicron) relapse (30% and 20%, respectively). Among them, 461 patients had comorbidities, with brain and neurological diseases (BND), malignancies and hematopoietic and blood disorders (HBDs) being the most common (6.7%, 2.6% and 2.1%, respectively). Real-time RT- PCR showed that 391 patients were positive. The mean age of the positive patients was 5.2 years. Most positive cases were in the fifth wave (30.9%), male (53.7%) and 1-5 years old (49.1%). BND (9.5%) and cardiovascular diseases (CVD) (4.3%) were common underlying conditions. A higher viral load (Ct score = 9-20) was most common in the fifth wave. Moreover, 8.7% of ICU admissions and 2.4% of deaths were due to a Ct score of 9-20. Most deaths occurred in the 1-5 age group and were associated with BND. More deaths occurred in women (73.9% overall, 71.4% real-time RT- PCR -positive), and the highest mortality was in the fifth wave. The risk ratio of mortality was higher in children with kidney disease (KD) and BND.

Conclusion

There were 27 ICU admissions (6.9%) and seven deaths (1.8%). The current study also revealed that children of any age can be susceptible to SARS-CoV-2 infection, while children aged 1-5 years are more susceptible to COVID-19. The Delta variant is associated with higher rates of hospitalization and ICU admission, and the presence of BND is associated with higher mortality rates.

Severe Neurological Complications With Influenza in Vietnamese Children

BACKGROUND

Influenza is a common contagious respiratory virus that primarily causes respiratory tract infections. Neurological complications associated with influenza have also been reported, mainly in pediatric populations, and may be fatal.

METHODS

A descriptive study evaluated pediatric patients who were diagnosed with severe influenza-associated neurological complications at the Tropical Pediatrics Center-Vietnam National Children's Hospital from October 2022 to February 2024.

RESULTS

In this study involving 20 patients, 80% of children were under 5 years old; 70% of patients had a history of good health. All patients had not received an influenza vaccination within 12 months. The median time from onset to neurological symptoms was 1 day. The most common neurological complication was encephalitis (16/20 patients) with symptoms included altered consciousness and seizures. Most patients had elevated levels of ALT (60%), AST (90%), LDH (94%), and ferritin (69%) in serum. The imaging of brain damage on MRI and CT scans varied in patterns and locations. There was no difference in the timing of methylprednisolone treatment within and after 48 h. The mortality rate was 20%, with 45% of patients experiencing severe sequelae.

CONCLUSIONS

IANCs are severe with damage to both white matter and central gray matter and can occur in healthy children, emphasizing the importance of vaccination to reduce the risk.

Characteristics and outcome of influenza-associated encephalopathy/encephalitis among children in China

BACKGROUND

Influenza-Associated Encephalopathy/Encephalitis (IAE) is characterized by high incidence and poor prognosis. The aim of this study is to describe the clinical features and outcomes of IAE in pediatric patients.

METHODS

We performed a retrospective review of hospitalized cases of laboratory-confirmed influenza infection between January 2018 and December 2021. Demographic, clinical, imaging, treatment and outcome data were collected. Statistical analysis was performed using SPSS software.

RESULTS

Of 446 children hospitalized with influenza, 71 cases were identified with a diagnosis of IAE. The median age was 3 years and 46 (64.8 %) were younger than 5 years. Only one patient was vaccinated for seasonal influenza. 46 (64.8 %) patients had abnormal electroencephalogram examination and 47 (66.2 %) had abnormal brain MRI or CT findings. 68 (95.8 %) patients were treated with oseltamivir/peramivir. 12 (16.9 %) patients suffered mortality. Non-survivors were more likely to have lower Glasgow coma score (median 7), longer duration of fever (median 3 days), with underlying medical conditions (P = 0.006), and complications including sepsis (P = 0.003), shock (P < 0.001), respiratory failure (P = 0.006), acute renal failure (P = 0.001), myocardial damage (P < 0.001), coagulation disorders (P = 0.03), electrolyte disturbance (P = 0.001) and hyperlactacidemia (P = 0.003). Non-survivors had higher percentages of corticosteroids (P = 0.003) and immunoglobulin (P = 0.003) treatments compared to survivors.

CONCLUSIONS

Children with IAE have a high mortality rate. Lower Glasgow coma score, longer duration of fever, with underlying medical conditions and complications pose a great risk to poor prognosis. Influenza vaccination is recommended to all eligible children.

A noninferiority randomized open-label pilot study of 3- versus 7-day influenza postexposure prophylaxis with oseltamivir in hospitalized children

Short influenza postexposure prophylaxis (PEP) showed high efficacy in adults, but studies in children are lacking. This randomized open-label pilot trial aimed to verify noninferiority of a 3- versus 7-day prophylaxis with oral oseltamivir in hospitalized children. Influenza contacts were randomized to the 3- or 7-day group and efficacy, relative risk of adverse events (AEs), and the cumulative costs of drugs and AEs management were compared. The intention-to-treat (ITT) analysis included 59 children (n = 28 and n = 31 in the 3- and 7-day group, respectively). The efficacy was 100% (95% CI 87.7-100%) versus 93.6% (95% CI 78.6-99.2%) in the 3- and 7-day group; the differences were statistically insignificant. A per-protocol (PP) analysis including 56 patients (n = 27 and n = 29, respectively) showed 100% (95% CI 87.2-100%) and 93.1% (95% CI 77.2-99.2%) efficacy, respectively, without statistical significance. Differences were within the predefined noninferiority margin with an efficacy difference Δ = 6.45 percentage points (p.p.) with 1-sided 95% CI (- 2.8, - 1.31, p = 0.86; ITT) and Δ = 6.9 p.p. (1-sided 95% CI - 2.83, - 1.27, p = 0.85; PP). Adverse events did not differ significantly, while the cumulative costs of the prophylaxis and AEs management were higher in the 7-day group (median 10.5 euro vs. 4.5 euro, p < 0.01). This pilot study showed the noninferiority of the 3-day versus 7-day PEP, which was associated with lower costs.Trial registration number: NCT04297462, 5th March 2020, restrospectively registered.

Viral entry and translation in brain endothelia provoke influenza-associated encephalopathy

Influenza-associated encephalopathy (IAE) is extremely acute in onset, with high lethality and morbidity within a few days, while the direct pathogenesis by influenza virus in this acute phase in the brain is largely unknown. Here we show that influenza virus enters into the cerebral endothelium and thereby induces IAE. Three-weeks-old young mice were inoculated with influenza A virus (IAV). Physical and neurological scores were recorded and temporal-spatial analyses of histopathology and viral studies were performed up to 72 h post inoculation. Histopathological examinations were also performed using IAE human autopsy brains. Viral infection, proliferation and pathogenesis were analyzed in cell lines of endothelium and astrocyte. The effects of anti-influenza viral drugs were tested in the cell lines and animal models. Upon intravenous inoculation of IAV in mice, the mice developed encephalopathy with brain edema and pathological lesions represented by micro bleeding and injured astrocytic process (clasmatodendrosis) within 72 h. Histologically, massive deposits of viral nucleoprotein were observed as early as 24 h post infection in the brain endothelial cells of mouse models and the IAE patients. IAV inoculated endothelial cell lines showed deposition of viral proteins and provoked cell death, while IAV scarcely amplified. Inhibition of viral transcription and translation suppressed the endothelial cell death and the lethality of mouse models. These data suggest that the onset of encephalopathy should be induced by cerebral endothelial infection with IAV. Thus, IAV entry into the endothelium, and transcription and/or translation of viral RNA, but not viral proliferation, should be the key pathogenesis of IAE.

Severe Influenza Virus and Respiratory Syncytial Virus Infections in Intensive Care Over the Last 15 Years

INTRODUCTION

Influenza virus is a common agent of pediatric infections. Most cases are mild, but severe illness and death can occur. We aimed to analyze severe cases associated the influenza virus and compare it with respiratory syncytial virus (RSV).

METHODS

This is a retrospective study of 0-17-year-old patients admitted to the intensive care unit (ICU) of Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra (Pediatric Hospital, Coimbra Hospital and University Center), a tertiary pediatric hospital in Coimbra, Portugal, over the last 15 years (2008-2022) due to influenza virus infection. Clinical presentation, severity, and evolution were analyzed. A comparison of children with RSV infection admitted in the same period was performed.

RESULTS

We identified 47 cases of influenza virus infection (34% coinfection with other viruses), median age of 2.3 years (interquartile range (IQR) 6.1), and 38% had comorbidities. The median admissions were three/year (maximum 11 in 2019). Influenza A was identified in 96%. Ninety-six percent had respiratory symptoms, 38% had neurologic symptoms, and 28% had sepsis. The main reason for admission was respiratory failure (68%). The mean pediatric index of mortality 2 (PIM2) at admission was 9±15.9%. Ventilatory support was necessary in 66%, vasoactive support in 19%, and blood products in 17%. The median length of stay was four days (IQR 5). There were four (8.5%) deaths. During the same study period, there were 171 RSV-related admissions. When comparing influenza (group A, without RSV coinfection) and RSV (group B), the first had a higher PIM2 on admission, greater need of ventilatory support, more complications, and higher mortality (p=0.001).

CONCLUSIONS

The number of influenza virus infections admitted to ICU was much lower than RSV. However, influenza was more severe and associated with all deaths registered.

Clinical Characteristics and Outcomes of Children With SARS-CoV-2 Infection During the Delta and Omicron Variant-Dominant Periods in Korea

BACKGROUND

Data on the clinical characteristics of pediatric patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant infection are limited. We aimed to evaluate the clinical features and outcomes of children with SARS-CoV-2 infection before and after omicron variant dominance in Korea.

METHODS

A multicenter retrospective cohort study was conducted in hospitalized patients aged ≤ 18 years with laboratory-confirmed SARS-CoV-2 infection at five university hospitals in South Korea. The study periods were divided into the delta (from August 23, 2021 to January 2, 2022) and omicron (from January 30 to March 31, 2022).

RESULTS

In total, 612 hospitalized patients were identified (211, delta; 401, omicron). During the omicron and delta periods, the proportions of individuals with serious illness (moderate, severe, and critical severity) were 21.2% and 11.8%, respectively (P = 0.034). Compared with the delta period, the proportions of patients with moderate illness increased significantly in the age groups of 0-4 years (14.2% vs. 3.4%) and 5-11 years (18.6% vs. 4.2%) during the omicron period. During the two periods, the proportions of patients with complex chronic diseases (delta, 16.0% vs. 4.3%, P = 0.040; omicron, 27.1% vs. 12.7%; P = 0.002), respiratory diseases except for asthma (delta, 8.0% vs. 0.0%, P = 0.013; omicron, 9.4% vs. 1.6%; P = 0.001), and neurologic diseases (delta, 28.0% vs. 3.2%, P < 0.001; omicron, 40.0% vs. 5.1%, P < 0.001) were significantly higher in patients with serious illness than in those with non-serious illness. During the delta period, the risk for serious illness was higher among patients with obesity (adjusted odds ratio [aOR], 8.18; 95% confidence interval [CI], 2.80-27.36) and neurologic diseases (aOR, 39.43; 95% CI, 6.90-268.3) and aged 12-18 years (aOR, 3.92; 95% CI, 1.46-10.85). However, the presence of neurologic disease (aOR, 9.80; 95% CI, 4.50-22.57) was the only risk factor for serious illness during the omicron period. During the omicron period, the proportions of patients with croup (11.0% vs. 0.5%) and seizures (13.2% vs. 2.8%) increased significantly compared with the delta period.

CONCLUSION

Compared with the delta period, the proportions of young children and patients with complex comorbidities were higher during the omicron period in Korea. Patients with complex chronic diseases, especially neurologic diseases, had a high risk of severe coronavirus disease 2019 in the two distinct variant-dominant periods.

Neurologic Manifestations of Influenza in Children

OBJECTIVE

We assessed the neurologic manifestation of influenza among hospitalized children with influenza (neuro-flu), comparing their demographic and clinical characteristics to hospitalized children without neurologic manifestation (classic-flu).

METHODS

A retrospective, cohort study. All children with laboratory confirmed influenza (PCR), admitted to the Soroka University Medical Center (SUMC) between 2016 and 2019 were included.

RESULTS

Overall, 951 patients were identified: 201 with neuro-flu, and 750 with classic-flu. Seizures (n = 125) were the most common neurological manifestation of neuro-flu (seizure-flu): 73 simple febrile seizures, 45 atypical febrile seizures, and 7 afebrile seizures. Neurological comorbidities rates were significantly higher in neuro-flu versus classic-flu (13.0% vs. 6.0%), while respiratory and cardiac comorbidities were less common in neuro-flu (4.5% and 0.5% vs. 8.0% and 4.5%, respectively). Neuro-flu (compared with classic-flu) was associated with leukocytosis (21.0% vs. 13.0%, P < 0.001) and lower C-reactive protein (CRP) levels (2.4 ± 4.1 vs. 3.3 ± 5.4, P = 0.03). Notably, patients with classic flu had a more prominent respiratory disease, as they had more chest radiographs (CXR) performed (60.5% vs. 45.0%, P < 0.001), higher rates of pneumonia (27.0% vs. 12.0%, P < 0.001), and antibiotic (antibacterial) treatment (60.0% vs. 42.0%, P < 0.001).

CONCLUSIONS

Influenza can appear as a neurologic disease, manifested mainly with febrile seizures. Children with neuro-flu have more neurologic comorbidities, suggesting that neuro-flu is mainly driven by host-factors, rather than by pathogen-factors. The relatively lower rates of pneumonia in neuro-flu suggests that these patients are admitted in the early stage of the influenza infection, which triggers the neurologic response.

Guideline-Concordant Antiviral Treatment in Children at High Risk for Influenza Complications

BACKGROUND

National guidelines recommend antiviral treatment for children with influenza at high risk for complications regardless of symptom duration. Little is known about concordance of clinical practice with this recommendation.

METHODS

We performed a cross-sectional study of outpatient children (aged 1-18 years) at high risk for complications who were diagnosed with influenza during the 2016-2019 influenza seasons. High-risk status was determined using an existing definition that includes age, comorbidities, and residence in a long-term care facility. The primary outcome was influenza antiviral dispensing within 2 days of influenza diagnosis. We determined patient- and provider-level factors associated with guideline-concordant treatment using multivariable logistic regression.

RESULTS

Of the 274 213 children with influenza at high risk for influenza complications, 159 350 (58.1%) received antiviral treatment. Antiviral treatment was associated with the presence of asthma (aOR, 1.13; 95% confidence interval [CI], 1.11-1.16), immunosuppression (aOR, 1.10; 95% CI, 1.05-1.16), complex chronic conditions (aOR, 1.04; 95% CI, 1.01-1.07), and index encounter in the urgent care setting (aOR, 1.3; 95% CI, 1.26-1.34). Factors associated with decreased odds of antiviral treatment include age 2-5 years compared with 6-17 years (aOR, 0.95; 95% CI, .93-.97), residing in a chronic care facility (aOR, .61; 95% CI, .46-.81), and index encounter in an emergency department (aOR, 0.66; 95% CI, .63-.71).

CONCLUSIONS

Among children with influenza at high risk for complications, 42% did not receive guideline-concordant antiviral treatment. Further study is needed to elucidate barriers to appropriate use of antivirals in this vulnerable population.

Severe Influenza-Associated Neurological Disease in Australian Children: Seasonal Population-Based Surveillance 2008-2018

BACKGROUND

Influenza-associated neurological disease (IAND) is uncommon but can result in death or neurological morbidity in children. We aimed to describe the incidence, risk factors, and outcome of children with IAND from seasonal influenza in Australia.

METHODS

We analyzed national, population-based, surveillance data for children aged ≤ 14 years with severe influenza and neurological involvement, over 11 Australian influenza seasons, 2008-2018, by the Australian Paediatric Surveillance Unit.

RESULTS

There were 633 laboratory-confirmed cases of severe influenza reported. Of these, 165 (26%) had IAND. The average annual incidence for IAND was 3.39 per million children aged ≤ 14 years. Compared to cases without neurological complications, those with IAND were more likely to have a pre-existing neurological disease (odds ratio [OR] 3.03, P < .001), but most children with IAND did not (n = 135, 82%). Children with IAND were more likely to receive antivirals (OR 1.80, P = .002), require intensive care (OR 1.79, P = .001), require ventilation (OR 1.99; P = .001), and die (OR 2.83, P = .004).

CONCLUSIONS

IAND is a preventable cause of mortality, predominantly in otherwise well children. Incidence estimates validate previous sentinel site estimates from Australia. IAND accounted for a quarter of all severe influenza, is associated with intensive care unit admission, and accounted for half of all influenza deaths.

Neurological complications associated with influenza in hospitalized children

BACKGROUND

Influenza is a known respiratory and potential neurotropic virus. This study aimed to determine the prevalence and outcomes of influenza-related neurological complications among hospitalized children.

METHODS

All medical records of hospitalized children aged <18 years old diagnosed with influenza at a tertiary care hospital in Bangkok were retrospectively reviewed. Influenza infection was confirmed by rapid antigen or reverse transcription polymerase chain reaction tests. Neurological characteristics and clinical outcomes were analyzed using the Pediatric Cerebral Performance Category Scale.

RESULTS

From 2013 to 2018, 397 hospitalized children with a median age of 3.7 years (interquartile range [IQR]: 1.6-6.9) were included. The prevalence of neurological complications, including seizure or acute encephalopathy, was 16.9% (95% confidence interval [CI]: 13.3-20.9). Influenza A and B were identified in 73.1% and 26.9% of the patients, respectively. Among 39 (58.2%) acute symptomatic seizure cases, 25 (37.3%) children had simple febrile seizures, 7 (10.4%) had repetitive seizures, and 7 (10.4%) had provoked seizures with pre-existing epilepsy. For 28 (41.8%) encephalopathy cases, the clinical courses were benign in 20 (29.9%) cases and severe in 8 (11.9%) cases. Ten (14.9%) children needed intensive care monitoring, and 62 (93.5%) fully recovered to their baselines at hospital discharge. Predisposing factors to the neurological complications included a history of febrile seizure (adjusted odds ratio [aOR]: 20.3; 95% CI: 6.6-63.0), pre-existing epilepsy (aOR: 3.6; 95% CI: 1.3-10.2), and a history of other neurological disorders (aOR: 3.5; 95% CI: 1.2-10.2).

CONCLUSIONS

One fifth of hospitalized children with influenza had neurological complications with a favorable outcome. Children with pre-existing neurological conditions were at higher risk for developing neurological complications.

Risk factors in pediatric hospitalization for influenza A and B during the seven seasons immediately before the COVID-19 era in Japan

INTRODUCTION

The risk factors in pediatric influenza immediately before the COVID-19 era are not well understood. This study aims to evaluate the risk factors for hospitalization in pediatric influenza A and B for the recent seasons.

METHODS

Children with a fever of ≥38 °C and laboratory-confirmed influenza at 20 hospitals in outpatient settings in Japan in the 2013/14 to 2019/20 seasons were retrospectively reviewed. Possible risk factors, including gender, age, comorbidities, nursery school or kindergarten attendance, earlier diagnosis, no immunization, lower regional temperature, earlier season, and period of onset, were evaluated using binary logistic regression methods.

RESULTS

A total of 13,040 (type A, 8861; B, 4179) children were evaluated. Significant risk factors (p < 0.05) in multivariate analyses were young age, lower regional temperature, earlier season, respiratory illness (adjusted odds ratio [aOR]:2.76, 95% confidence interval [CI]:1.84-4.13), abnormal behavior and/or unusual speech (aOR:2.78, 95% CI:1.61-4.80), and seizures at onset (aOR:16.8, 95% CI:12.1-23.3) for influenza A; and young age, lower regional temperature, respiratory illness (aOR:1.99, 95% CI:1.00-3.95), history of febrile seizures (aOR:1.73, 95% CI:1.01-2.99), and seizures at onset (aOR:9.74, 95% CI:5.44-17.4) for influenza B.

CONCLUSIONS

In addition to previously known factors, including young age, seizures, and respiratory illness, abnormal behavior and/or unusual speech and lower regional temperature are new factors. Negative immunization status was not a risk factor for hospitalization. A better understanding of risk factors may help improve the determination of indications for hospitalization during the future co-circulation of influenza and COVID-19.

The recent characteristics of influenza-related hospitalization in Japanese children

We investigated the recent epidemiology and characteristics of influenza-related hospitalization in Japanese children. This study included 3741 children with influenza. Children hospitalized for febrile seizures (FS) induced by etiologies other than influenza also served as a disease control. Most outpatients (92.8%) visited our hospital with complaints of respiratory symptoms, whereas FS were the most predominant symptoms of inpatients (58/154, 37.7%). Children with influenza-induced FS were significantly older than those with FS induced by other etiologies (P <0.001). Although the characteristics of severe influenza may vary throughout the world, the analysis of influenza-induced neurological disorders is important for understanding its epidemiology.