Preliminary clinical tests show that a bird flu vaccine for human use created by Chinese scientists is safe and effective, researchers said yesterday.

The vaccine was jointly developed by China's Ministry of Science and Technology, Center for Disease Control and Prevention and Beijing Sinovac Biotech Co, a Beijing-based pharmaceutical company.

The clinical tests began last November at the Beijing China-Japan Friendship Hospital after the State Food and Drug Administration granted the vaccine developers the green light for the trials.

Results from the first-phase tests, which ended in June, showed that the four antigens in the vaccine stimulated the production of antibodies, according to the pharmaceutical company.

It said a 10 microgram dose of the vaccine proved to be the most effective, stimulating a 78.3 percent response in protective antibodies, exceeding the European Union standard of 70 percent for a flu vaccine.

The 120 participants who were vaccinated showed no serious adverse reactions, researchers said. Blood tests and urine tests all indicated that the vaccine is safe for human use, according to the scientists.

The vaccine was developed from a strain of the virus provided by the World Health Organization and is meant to protect against the deadly H5N1 strain of avian influenza.

Beijing Sinovac Biotech Co said it is ready to apply for the second phase of clinical trials. In China, a vaccine is allowed to enter the market after it completes three rounds of tests.

Bird flu remains essentially an animal disease, but experts fear the H5N1 virus could mutate into a form that could pass easily among humans.

Worldwide, about a dozen companies are currently conducting clinical trials of bird flu vaccines.