Chinese researchers reported, for the first time, clinical evidence of oseltamivir (Tamiflu) resistance in patients infected with the novel avian H7N9 flu.
In a small case series of 14 patients, treatment with antiviral medications led to a lowering of viral load on throat swabs in all but three, according to Zhenghong Yuang, PhD, Shanghai Medical College of Fudan University in China, and colleagues.
Those three developed severe illness that required extracorporeal membrane oxygenation (ECMO), and two died. A viral mutation associated with drug resistance was isolated from two of them, but not from others, Yuang and colleagues reported online in The Lancet.
And, they wrote, “the apparent ease with which antiviral resistance emerges … is concerning; it needs to be closely monitored and considered in future pandemic response plans.”
The study was supported by the National Megaprojects of China for Infectious Diseases, the National Natural Science Foundation of China, the Ministry of Science and Technology, the Shanghai Municipal Health and Family Planning Commission, and the National Key Basic Research Program of China.
– By Michael Smith, North American Correspondent, MedPage Today Published: May 28, 2013
Reviewed by Zalman S. Agus, MD; Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Primary source: Lancet
Hu Y, et al “Association between adverse clinical outcome in human disease caused by novel influenza A H7N9 virus and sustained viral shedding and emergence of antiviral resistance” Lancet 2013; DOI: 10.1016/S0140-6736(13)61125-3.