BEIJING - Chinese studies of a H7N9 bird flu vaccine needs technical support and cooperation from the World Health Organization (WHO) as well as related professional institutions, an official said on Wednesday.

"It's a hard job to develop the H7N9 vaccine, which can take a long time," said Yang Weizhong, deputy director with the Chinese Center for Disease Control and Prevention, at a China-WHO meeting on preventing and dealing with H7N9 bird flu.

Nancy Cox, a WHO official, said that it is wise for some countries to launch early studies of H7N9 vaccines, which will help select suitable H7N9 virus strains for research.

Some countries started to develop bird flu vaccines three years ago, she said, adding that the WHO has organized nations to select from many candidate vaccines via network monitoring global laboratories.

A total of 108 H7N9 cases have been reported in the Chinese mainland, including 23 that have ended in death, since the first infections were announced on March 31. Taiwan reported its first case on Wednesday.