Objective: To analyze the epidemiology and clinical characteristics of influenza A (H1N1).
Methods: A retrospective analysis was performed on the clinical data of 137 cases of influenza A (H1N1) admitted into our hospital during May to August 2009.
Results: In the early stage, most cases were imported from the US, Australia, Canada and the UK. While in the later stage, most of them were secondary. The patients were mainly children and youngsters. And the most common clinical manifestations were fever (n = 108), cough (n = 93) and sore throat (n = 67) while the most common signs congestive throat (n = 99) and swelling tonsil (n = 46). The average fever period was 3.3 ± 1.5 days. The clinical symptoms vanished in 4.4 ± 1.9 days. And the average length of stay was 5.5 ± 2.1 days. Laboratory tests: the count of leukocytes declined while that of lymphocytes increased in 39 cases (39.5%). The test of influenza A (H1N1) nucleic acid was positive. The chest radiograph showed intensive pulmonary markings or patchy pneumonia-like signs.
Treatments: the groups of patients using Chinese herbs, western medicine plus Chinese herbs, symptomatic relief and placebo showed no significant difference in fever period, recovery time and the negative-converting period of influenza A (H1N1) nucleic acid tests became negative.
Conclusion: Influenza A (H1N1) may be recessive or dominant. Despite a strong infectivity, the clinical symptoms are mild and the clinical course is self-limited, similar to the seasonal influenza.