Mainland authorities declared the first phase of clinical trials of a homegrown HIV vaccine a success yesterday, but a medical expert doubts the test product will pass its second human trial phase. The vaccine, produced by Changchun BCHT Pharmaceutical, was injected into dozens of volunteers in March last year, and no adverse reactions were registered in six months of monitoring, China National Radio reported. Some volunteers also developed specific cellular immunity against the virus. The results were announced yesterday by Zhang Wei , from the State Food and Drug Administration (SFDA), and Sang Guowei , from the National Institute for the Control of Pharmaceutical and Biological Products. BCHT Pharmaceutical general manager Kong Wei , who is also a Jilin University biochemistry professor, said the first human trials were mainly designed to test the vaccine's safety. A total of 49 healthy people aged 18 to 50 took part in the trial at the Guangxi Centre for Disease Control and Prevention on a double-blind basis, meaning that neither doctors nor volunteers knew who had been given the vaccine. 'In the bodies of the first batch of eight volunteers, we found the specific cell-mediated immunity against HIV developed within 15 days,' China National Radio quoted Professor Kong as saying. Feng Daqiang , the deputy manager of the vaccine manufacturer, said the company had already prepared enough vaccine for the second stage of testing but had been waiting for the nod from the SFDA to proceed. About 200 to 300 people will be involved in the second stage of clinical tests, of whom half would be volunteers from high-risk populations, especially drug addicts in Guangxi , according to the Shanghai Morning Post. But Peking University Medical School professor Zhuang Hui said the much larger number of people in the second phase meant it would be much harder to demonstrate the vaccine's effectiveness. 'More problems can occur in a larger group than in a small group. What's more, it will apply to high-risk people and they have poorer health and lower immunity,' Professor Zhuang said. 'The future for the HIV vaccine is not too bright.' Only two HIV vaccines in the world have gone on to third-stage trials, the Shanghai Morning Post reported.