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Published on: January 30, 2017
Signs and symptoms predicting influenza in children: a matched case-control analysis of prospectively collected
S Heinonen1, V Peltola, H Silvennoinen
1Department of Pediatrics, Turku University Hospital, Kiinamyllynkatu 4-8, 20520, Turku, Finland. shhein@utu.fi
Insights
Fever is the sole reliable indicator distinguishing influenza from other respiratory infections in children. Higher temperatures significantly increase the likelihood of influenza, suggesting careful clinical assessment is vital.
Area of Science:
- Pediatric Infectious Diseases
- Clinical Virology
- Epidemiology
Background:
- Differentiating influenza from other respiratory infections in children can be challenging for clinicians.
- Accurate diagnosis is crucial for timely and appropriate treatment, including the use of antiviral medications.
Purpose of the Study:
- To identify specific clinical signs and symptoms that can reliably distinguish influenza from other respiratory infections in pediatric patients.
- To evaluate the predictive value of fever, including its severity, in diagnosing influenza.
Main Methods:
- A matched case-control analysis was conducted using data from a 2-year prospective cohort study.
- Participants included 353 children with laboratory-confirmed influenza (cases) and 353 children with non-influenza respiratory symptoms (controls), matched for age, gender, and visit timing.
- Clinical examinations and virologic analyses of nasal swabs were performed.
Main Results:
- Fever was the only clinical sign that independently predicted influenza virus infection in children.
- The odds ratio for influenza increased significantly with higher fever temperatures, ranging from 13.55 to 50.10.
- A fever of ≥40.0°C had a likelihood ratio of 6.00 for predicting influenza.
Conclusions:
- Fever is the most reliable clinical predictor of influenza virus infection in outpatient pediatric settings during outbreaks.
- The degree of fever correlates with the likelihood of influenza, with higher temperatures being more predictive.
- Virologic confirmation is recommended for optimal use of influenza-specific antiviral drugs in children.
Abstract:
We aimed to determine whether there are signs or symptoms that could help clinicians to distinguish between influenza and other respiratory infections. The clinical data for this matched case-control analysis were derived from a 2-year prospective cohort study of respiratory infections among children aged≤13 years. At any signs of respiratory infection, the children were examined and nasal swabs were obtained for virologic analyses. Cases were 353 children with laboratory-confirmed influenza and controls were 353 children with respiratory symptoms who tested negative for influenza. Cases and controls were matched for gender, age, and timing of the visit. In the multivariate conditional logistic regression analyses, fever was the only sign that independently predicted influenza virus infection, with odds ratios ranging from 13.55 (95% confidence interval [CI], 6.90-26.63) to 50.10 (95% CI, 16.25-154.45), depending on the degree of fever. In all analyses, the predictive capability of fever increased with incremental elevations in the child's temperature. The likelihood ratio of fever≥40.0°C in predicting influenza was 6.00 (95% CI, 2.80-12.96). Among unselected children seen as outpatients during influenza outbreaks, fever is the only reliable predictor of influenza virus infection. The optimal use of influenza-specific antiviral drugs in children may require virologic confirmation.
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