Clinical features of initial cases of 2009 pandemic influenza A (H1N1) in Macau, China.

Background: The first case of pandemic influenza A (H1N1) virus infection in Macau Special Administrative Region (SAR) of the People's Republic of China was documented on June 18, 2009. Subsequently, persons with suspected infection or of contact with suspected cases received screening. All the confirmed cases were hospitalized and treated with oseltamivir. Their clinical features were observed. This may help for better management for later patients and be of benefit to the government of Macau SAR to adjust its strategy to combat the pandemic influenza A (H1N1) virus infection more efficiently.

Methods: From June to July 2009, the initial 72 cases of influenza A (H1N1) in Macau were hospitalized in Common Hospital Centre S. Januario (CHCSJ). The infection was confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR). The clinical features of the disease were closely observed and documented. Oseltamivir was given to all patients within 48 hours after the onset of disease and maintained for 5 days.

Results: The mean age of the 72 patients was 21 years old. Forty of them were men and 32 were women. The median incubation of the virus was 2 days (1 to 7 days). The most common symptoms were fever (97.2%) and cough (77.8%). The rate of gastrointestinal symptoms including nausea, vomiting, and diarrhea was 2.8%. Fever typically lasted for 3 days (1 to 9 days). The median time from the onset to positive results of real-time RT-PCR was 6 days (3 to 13 days). After treatment with oseltamivir, most patients became afebrile within 48 hours. Only one aged patient with a history of glaucoma and hypothyroidism was found to have lung infiltration on chest X-ray.

Conclusions: The initial cases of pandemic influenza A (H1N1) virus infection in Macau SAR showed that most of the infected persons had a mild course. The virus could be detected by real-time RT-PCR within a median of 6 days from the onset. Oseltamivir was effective.