400 volunteers are needed for the second round of testing of a
bird flu vaccine, after the first phase of clinical trials showed
that it is safe for human use.
The second phase of clinical trials, being considered by the State
Food and Drug Administration (SFDA), would test how long the
vaccine would protect the human body against the deadly H5N1 virus,
said Lin Jiangtao, one of the doctors leading the program at the
Sino-Japanese Friendship Hospital where the first round of testing
"The second phase will need 300 to 400 volunteers," said Lin,
adding that the exact number would be decided by the SFDA.
Results from the first round, which ended in June, showed that the
120 people who were vaccinated had no serious adverse
Lin said that mild fever after inoculation was a normal
The trials indicated that a 10-microgram dosage of the vaccine gave
the best results, stimulating 78.3 percent of protective
antibodies, exceeding the European Union standard of 70 percent for
a flu vaccine.
The second phase would test similar dosages on volunteers to find
out how best to stimulate the most antibodies, which requires a
larger pool of volunteers, Lin said.
Prospective volunteers should be aged 18 to 65, but children and
pregnant women will not be allowed to participate.
The vaccine must undergo three rounds of testing before it is
allowed on the market, researchers said.
Sinovac Biotech Limited, which jointly developed the vaccine with
the Ministry of Science and Technology and the Center for Disease
Control and Prevention, announced earlier this week that it would
expand production facilities to produce massive quantities of human
bird flu vaccine once testing is complete.
Bird flu remains essentially an animal disease, but experts fear
that the H5N1 virus could mutate into a form that could spread
easily among humans.
The virus has killed 14 people in China since 2003.
(Xinhua News Agency September 1, 2006)