Laboratory tests have detected Tamiflu resistance in 3 H7N9 cases.

Tamiflu is used to treat avian flu. (Photo: Reuters)

The Lancet magazine on Tuesday unveiled a study by Chinese scientists on 14 H7N9 patients treated with antiviral drugs at the Shanghai Public Health Clinical Centre. Researchers said 11 out of the 14 showed a positive response but the other 3 saw no improvement, even a higher viral index. The 3 patients received respiratory support but 2 of them have died. According to the researchers, the antiviral drug resistance of H7N9 virus is disturbing. Of 130 cases, 37 avian flu deaths have been confirmed so far in China.