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Published on: September 19, 2025
[Clinical characteristics of patients with infection due to Influenza A (H1N1) 2009 and critical pathology]
J L Pérez Navero1, J Rumbao Aguirre, A Correas Sánchez
1Intensivos Pediátricos, Unidad de Gestión Clínica de Pediatría y sus Especialidades, Hospital Universitario Reina Sofia, Córdoba, Spain. ucip.hrs.sspa@juntadeandalucia.es
Insights
Children with risk factors face a higher risk of severe outcomes from Influenza A (H1N1), particularly those needing intensive care. Monitoring RT-PCR for Influenza A (H1N1) can guide isolation duration.
Area of Science:
- Pediatric Infectious Diseases
- Virology
- Critical Care Medicine
Context:
- Influenza A (H1N1) caused significant pediatric hospitalizations during the 2009-2010 season.
- Intensive therapy was required for a subset of these hospitalized children.
Purpose:
- To analyze risk factors, clinical presentation, and outcomes of children hospitalized with Influenza A (H1N1).
- To compare critically ill children (Group I) with non-critically ill hospitalized children (Group II).
Summary:
- The study included 38 children, with 6 requiring intensive care. Critically ill patients had a higher prevalence of risk factors and respiratory symptoms.
- Complications included ARDS, myocarditis requiring ECMO, and multi-organ dysfunction. Mortality was higher in the intensive care group.
- Oseltamivir treatment duration and RT-PCR negativity time were longer in critically ill patients.
Impact:
- Identifies risk factors associated with severe Influenza A (H1N1) in children.
- Highlights the increased mortality and complications in critically ill pediatric patients.
- Suggests RT-PCR monitoring can inform isolation protocols for Influenza A (H1N1).
Objective:
Retrospective, observational study in children hospitalized due to Influenza A (H1N1) between October 2009 and February 2010, emphasizing on those who required intensive therapy.
Material And Methods:
Risk factors, symptoms, course, complications, mortality, time of disappearance of RT-PCR Influenza A (H1N1), average length of stay and duration of treatment with oseltamivir, were studied, comparing critically ill patients (group I) with the rest of hospitalized patients (group II).
Results:
A total of 38 children, with a mean age of 5.03±4.6 years were admitted during the study period. Six patients required intensive care, 83.3% had risk factors for influenza A (H1N1) compared with 62.5% in group II. Fever > 38°C was the predominant symptom (92.1%). Respiratory symptoms were significantly more frequent in group I (83.3% vs. 33.6; P<.01). Two critically ill patients required mechanical ventilation due to ARDS (acute respiratory distress syndrome). One patient with exacerbation of chronic respiratory failure responded favourably to high-flow oxygen. One patient developed fulminant myocarditis and required ECMO (Extracorporeal Membrane Oxygenation) because of secondary cardiogenic shock, which developed into multiple organ dysfunction and brain death. Oseltamivir therapy was given for an average of 8.6 days in group I and 4.5 days in group II (P<.05), checking the negativity of RT-PCR Influenza A (H1N1) in 7±2 days. The average stay was significantly higher in group I. Two patients admitted to PICU died.
Conclusions:
The presence of risk factors increases the likelihood of unfavourable outcome: high mortality among patients requiring intensive care. Monitoring of RT-PCR Influenza A (H1N1) could help establish the duration of isolation measures.
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