Article in Japanese

Clinicoepidemiological characteristics of 2009 pandemic influenza A (H1N1) virus infection Focus: mild cases in children

Masahiro UENO^1,3), Eiji KUDE²⁾, Minoru SUGITA³⁾

Results from epidemiological analysis of 2009 pandemic influenza A (H1N1) virus infection focused on mild cases in children suggest that anti-influenza virus drugs (Oseltamivir and Zanamivir) are extremely effective in alleviating fever symptoms. The drugs took effect immediately and prevented the duration of fever from lasting. Temperatures quickly stabilized at normal levels roughly 21 hours after administration of these drugs. There were no patients whose fever lasted more than 48 hours. The total duration of fever was typically 36.0±12.3 hours (mean±SD) and the duration of defervescence after prescription of anti-influenza virus drugs was 21.0±9.0 hours.
All study patients were mild cases who had been prescribed anti-influenza drugs within 2 days after the onset of fever, whose temperatures had stabilized within several days, and who had not been hospitalized.
In clinical findings, it appeared that coughing was the most common symptom (84%) and that digestive symptoms accounted for 9-14%.
Sexuality can serve as an early warning sign to predict the total duration of a fever. That is, male children had fever for a significantly longer duration than female children (mean: 6.6 hours) (p=0.015).
Coughing can also serve as an early warning sign to predict the total duration of a fever. That is, children who coughed had fever for a significantly longer duration than those who did not cough (mean: 9.3 hours) (p=0.012).
The sooner drugs can be administered, the greater the reduction of the fever's total duration can be expected (mean: 15.3 hours) (p<0.001).

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1) Hasuda Isshinkai Hospital
2) Kude Children's Clinic
3) Department of Environmental and Occupational Health, Toho University School of Medicine

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Received	January 25, 2010
Accepted	August 23, 2010

22 (4)：349─355,2010