China reported more human cases of H7N9 on Saturday after researchers in Shanghai announced preliminary success in developing a vaccine.

The health authority in east China's Zhejiang Province confirmed a human case of H7N9 bird flu, bringing the number of human cases in the province to 74 so far this year.

The patient is a 61-year-old man from Xiaoshan District of Hangzhou, capital city of Zhejiang. He is in a critical condition.

East China's Jiangsu Province on Saturday reported a human infection in a 53-year-old man, and a death. The number of H7N9 human cases in the province in 2014 is 12.

Officials with Shanghai Public Health Clinical Center told Xinhua that their genetically-engineered vaccine passed the preliminary animal tests of laboratory mice.

Xu Jianqing, a professor with the center, said the vaccine would have to go through a clinical test to prove its effectiveness in protecting humans before being put into use.