The First 100 Hospitalized Severe Complicated Influenza Cases Caused by 2009 Pandemic Influenza A (H1N1) in Taiwan

Yu-San Chien

2009 Vol.25 NO.10

Correspondence Author: Jen-Hsiang Chuang


To understand the features of the severe complicated influenza patients caused by 2009 pandemic influenza A (H1N1), we retrospectively reviewed the medical records of the first 100 laboratory-confirmed cases (by date of onset), analyzed all clinical variables and described their clinical and epidemiologic characteristics.
The cases had onset dates from July 2 to August 29, 2009, half of them were adults and the other half was children. The median age was 16.5 years. Thirty-eight had preexisting medical conditions, 6 of the 50 adults were morbidly obese, 8 of the 50 children were obese, and 2 women were pregnant. The most common initial presentations were fever (99%) and cough (93%). Eighty-nine patients had viral pneumonia, 23 were complicated with respiratory failure requiring mechanical ventilation, and 9 were treated with concomitant support by extracorporeal membrane oxygenation. By September 18, 82 patients recovered and were discharged from the hospitals; 9 were still hospitalized; and the remaining 9 patients (including 2 obese patients and one pregnant woman) died. The median time between onset of symptoms and first doctor visit was 1 day, and the median hospital stay for those who had been discharged was 6 days. The average duration from onset of symptoms to the date of rapid testing, admission, or prescription of oseltamivir for patients with onset after August 15 was shorter then those with onset before August 15.
In conclusion, most of the severe complicated influenza patients caused by 2009 pandemic influenza A (H1N1) were children and young to middle-aged adults; overweight and pregnancy posed higher risk to these patients. The preventive and control measure conducted by the public health sector have effectively accelerated diagnosis and treatment. However, quality of medical care remains to be improved to further reduce the number of severe complicated influenza cases and mortality.
Keywords: 2009 pandemic influenza A (H1N1), severe complicated influenza infection, retrospective analysis