# 4145
In one of the most in-depth studies released to date, we get a look at the clinical details of 426 laboratory confirmed cases of H1N1 infection in China from last May and June.
I’ve excerpted parts of the abstract below (slightly reparagraphed for readability), but follow the link to read the entire study.
Published at www.nejm.org December 9, 2009 (10.1056/NEJMoa0906612)
Clinical Features of the Initial Cases of 2009 Pandemic Influenza A (H1N1) Virus Infection in China
Bin Cao, M.D., Xing-Wang Li, M.D., Yu Mao, M.D., Jian Wang, M.D., Hong-Zhou Lu, M.D., Yu-Sheng Chen, M.D., Zong-An Liang, M.D., Lirong Liang, M.D., Su-Juan Zhang, M.D., Bin Zhang, M.D., Li Gu, M.D., Lian-He Lu, M.D., Da-Yan Wang, Ph.D., Chen Wang, M.D., for the National Influenza A Pandemic (H1N1) 2009 Clinical Investigation Group of China
ABSTRACT
Methods During May and June 2009, we observed 426 persons infected with the 2009 pandemic influenza A (H1N1) virus who were quarantined in 61 hospitals in 20 provinces.
Results The mean age of the 426 patients was 23.4 years, and 53.8% were male. The diagnosis was made at ports of entry (in 32.9% of the patients), during quarantine (20.2%), and in the hospital (46.9%).
The median incubation period of the virus was 2 days (range, 1 to 7).
The most common symptoms were fever (in 67.4% of the patients) and cough (69.5%). The incidence of diarrhea was 2.8%, and the incidence of nausea and vomiting was 1.9%.
Lymphopenia, which was common in both adults (68.1%) and children (92.3%), typically occurred on day 2 (range, 1 to 3) and resolved by day 7 (range, 6 to 9). Hypokalemia was observed in 25.4% of the patients. Duration of fever was typically 3 days (range, 1 to 11).
Conclusions Surveillance of the 2009 H1N1 virus in China shows that the majority of those infected have a mild illness. The typical period during which the virus can be detected with the use of real-time RT-PCR is 6 days (whether or not fever is present). The duration of infection may be shortened if oseltamivir is administered.
