New vaccines developed to stop bird flu
Updated: 2005-05-26 11:11
HARBIN -- Chinese scientists announced Wednesday two newly developed vaccines
are fully capable of stopping the spread of the deadly H5N1 strain of the bird
flu virus to fowl, water birds, mammals or humans.
They also said they are willing to provide technical support inepidemic
prevention to other countries and regions and contribute to the breeding
industry 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: having passed a state-level
appraisal, plus a permit granted by the Chinese 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 percent," said Chen.
In the meantime, China has developed three new technologies with which it
takes less than 10 hours to confirm a bird flu epidemic, comparing 72 hours in
the past, with more time being gained for prevention measures or for taking
Dr. Bernard Vallat, Director General of World Organization for Animal Health
(OIE), said China leads the world in research on bird flu and relevant
technologies for prevention.
More of the two new vaccines have been sent to Gangcha County, where dead
migratory birds, confirmed by Chen's lab to be caused by the deadly H5N1 virus,
were found on May 4, in a bid to preventthe deadly avian disease from further
The Chinese 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 when China successfully wiped out the primarily
avian-borne epidemic disease.
Sources said some of the dead migratory birds discovered in Gangcha County,
northwest China's Qinghai Province, migrated from Southeast Asia. Migration is
blamed as an important for spreading of bird flu virus, and China is on the
route of migratory birds inAsia.
There is a higher risk for waterfowl to be 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 the
water birds infected withthe H5N1 virus.
There were no reports in the world of vaccines being tested on water birds
before China began its research. The latest experimental results show that the
newly developed vaccines of Chen's lab are equally effective in water fowl, and
ducks and geese, which when inoculated with the vaccines did not develop bird
"With the vaccines, one activated and the other inactivated, the important
way for spreading of bird flu virus can be cut off,"said Chen.
Compared with conventional ones, the inactivated bird flu vaccine can provide
stronger protection against infection in waterbirds such as ducks and geese upon
inoculation, while the term of effectiveness on chickens will be prolonged by
four months. The bird flu activated vaccine can produce a protection shield
againstassault of the H5N1 virus in fowls within nine months after inoculation.
"Both the activated and inactivated vaccines are safe to food security, as
the meat of fowls being inoculated with the vaccines have been shown not to be
affected," said Chen.
An estimate made in February 2004 by UN Food and Agricultural Organization
(FAO) said about 100 million domestic fowl died of the H5N1 virus or were culled
because of the infection between late 2003 and 2004. Direct economic losses were
placed at 500 million US dollars.
At least 52 people in Vietnam, Thailand and Cambodia were diagnosed as being
infected with the bird flu virus and died.
World Health Organization (WHO) warned over one million more people could die
if the H5N1 virus were spread from human to human.The human deaths caused by the
common flu each year are between 250,000 and 500,000, but scientists believe
mortality caused by the bird flu among human beings would be much higher.
According to Chen, some chicken farms in Vietnam have been conducting
experiments with the new bird flu vaccines developed byChen's lab over safety
Agricultural officials in Vietnam said they would inoculate alltheir domestic
fowl with the new bird flu vaccines once the experiments prove positive.
"We will spare no effort in offering support to other countriesif necessary,"
the Chinese scientist promised.