By Nigel Hawkes, Health Editor
A CHINESE vaccine against H5N1 bird flu has raised hopes of swift protection if the virus mutates into a pandemic form.
Trials of the vaccine in 120 volunteers showed that it produced a good immune response at low doses. In an emergency, enough could be produced for 675 million people.
The Chinese vaccine consists of the H5N1 avian flu virus inactivated so that it cannot cause disease, combined with an additive (adjuvant) that enhances the immune response.
A group of 120 volunteers aged between 18 and 60 were given either a dummy formula or the vaccine at doses of 1.25, 2.5, 5 and 10 micrograms with aluminium hydroxide as the adjuvant.
After 56 days, the researchers report in The Lancet online, all of the vaccine doses produced antibodies against the virus, with the best response in the 10-microgram group. This dosage stimulated 78 per cent protective antibodies, exceeding the European Union minimum requirement of 70 per cent, and it was well tolerated with relatively few side-effects.
The manufacturer is Sinovac Biotech, a Beijing-based pharmaceutical company, which jointly developed it with the Chinese Science and Technology Ministry and the country’s Centre for Disease Control and Prevention.
In a review of the work, Iain Stephenson, of the Infectious Diseases Unit at the University of Leicester, said that the big advantage of the Chinese design was its successful use of a whole virus, rather than parts of it, to stimulate an immune response.
Whole-virus vaccines are known to trigger a bigger immune response, although they often cause more side-effects.
Because the dosage is lower than in previous vaccines, more could be produced in the crucial first six months after the start of a pandemic.