In late March 2013, investigators confirmed that 3 patient deaths in China were due to a novel avian-origin influenza virus, H7N9. A new analysis of data from 111 patients diagnosed with the virus through May 10, 2013, shows that the virus caused severe illness in more than three quarters of confirmed cases and death in more than one quarter.
Hai-Nv Gao, MD, from the State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University in Hangzhou, China, and colleagues report their findings in an article published online May 22 in the New England Journal of Medicine.
The researchers analyzed medical record data from patients with avian-origin influenza A (H7N9) infection. Diagnosis was confirmed by real-time reverse-transcriptase–polymerase chain reaction assay, viral isolation, or H7N9 serologic testing using modified hemagglutination-inhibition assays.
Of those patients, 76.6% were severely ill and admitted to an intensive care unit, and 27.0% died. The most frequent complications were moderate-to-severe acute respiratory distress syndrome (ARDS) (79 patients), shock (29 patients), acute kidney injury (18 patients), and rhabdomyolysis (11 patients).