HARBIN: Chinese scientists announced on Wednesday that they have developed two new vaccines capable of stopping the spread of the deadly H5N1 strain of bird flu to birds, mammals and humans.
They also said they are willing to provide details of epidemic prevention to other countries and regions, and contribute to agriculture and public health security worldwide.
Chen Hualan, director of the China National Bird Flu Reference Laboratory, based in Harbin, capital of Heilongjiang Province, said the two new vaccines developed by her lab had proved to be a success.
She said they had passed a State-level appraisal, and had obtained a permit granted by the Ministry of Agriculture for sale on the market.
"Experiments show the efficiency rate of the newly developed vaccines in preventing infection by the H5N1 virus is 100 per cent," claimed Chen.
In the meantime, China has developed three new technologies which in less than 10 hours can confirm a bird flu epidemic.
In the past, it took 72 hours to get confirmation.
Dr Bernard Vallat, director-general of the World Organization for Animal Health, said China leads the world in research on bird flu and relevant technologies for its prevention.
Samples of the two new vaccines have been sent to Gangcha County, Qinghai Province, where dead migratory birds - confirmed by Chen's lab to have died after catching the deadly H5N1 virus - were found on May 4. The vaccines will help prevent the deadly avian disease from spreading.
The Ministry of Agriculture also made an announcement about the incident last Saturday. It is the first reported bird flu case on the Chinese mainland since last year.
Sources said some of the dead migratory birds discovered in Gangcha County migrated from Southeast Asia. Migration is blamed for spreading the bird flu virus, and China is a main stopping-off point for migratory birds in Asia.
There is a high risk of waterfowl becoming infected with the deadly bird flu virus after mingling with migratory birds already carrying the killer disease. The bird flu virus can easily spread to domestic fowl and even humans via birds infected with the H5N1 virus.
There have been no other reports of vaccines being tested on water birds before China began its research. The latest experimental results show that the newly developed vaccines are equally effective in fowl such as ducks and geese, which when inoculated with the vaccines did not develop bird flu symptoms.
"With these vaccines, one 'activated' and the other 'inactivated,' a major way for the spread of the bird flu virus can be eradicated," said Chen.
Compared with conventional vaccines, the inactivated bird flu vaccine can provide stronger protection against infection in water birds such as ducks and geese upon inoculation. The bird flu activated vaccine can produce a protective shield against the H5N1 virus in fowls within nine months after inoculation.
"Both the activated and inactivated vaccines will not affect food security," said Chen.
An estimate made in February last year by the United Nations Food and Agriculture Organization found that about 100 million domestic fowl died of the H5N1 virus or were culled because they were infected between late 2003 and 2004. Direct economic losses were placed at US$500 million.
At least 52 people have died in Viet Nam, Thailand and Cambodia after being diagnosed as having bird flu.
The World Health Organization has warned that over 1 million more people could die if the H5N1 virus spreads among people.
The number of human deaths caused by common flu each year is between 250,000 and 500,000, but scientists believe mortality caused by bird flu could be much higher.
According to Chen, some chicken farms in Viet Nam have been conducting experiments with the new vaccines developed by Chen's lab to check their safety and effectiveness.
Agricultural officials in Viet Nam said they would inoculate all their domestic fowl with the new bird flu vaccines once the experiments prove positive.
"We will spare no efforts in offering support to other countries if necessary," the Chinese scientist promised.
(China Daily 05/27/2005 page3)
