Tuesday, February 08, 2005

Chinese bird flu vaccine: two steps forward or one step back?

Well, it sounds like good news:
Scientists in China have developed a new longer-lasting vaccine for poultry and mammals designed to prevent the spread of the deadly bird flu virus, official state media reported Monday.

The new vaccine is said to protect chickens for 10 months, four months longer than existing vaccines.

Thus far this year, China has not reported any outbreaks of bird flu in the country.

The new vaccine was developed using a genetically-altered bird flu virus, according to reports from China's official daily newspaper.

The World Health Organization has warned that bird flu could trigger an international pandemic if the virus mutated into a form that could easily pass from human to human. The WHO said the pandemic could kill up to 7 million people. (Health Talk)
But the "back story" isn't quite so hopeful (Asia News, Italian edition):
The developers have said the vaccines represent a breakthrough in the fight against the deadly H5N1 strain of the virus. But sources connected to the research project said the vaccines were not necessarily more effective than one now being used, which was also developed by the Harbin Veterinary Research Institute.

"Essentially there are no differences," said a source close to the institute's Key Lab of Animal Influenza, which developed the new vaccines. According to the Ministry of Agriculture, the vaccines can protect chickens against bird flu for 10 months - four months longer than the existing vaccine. But the source said the 10 months' protection was achieved under laboratory conditions and "we would consider ourselves very lucky if that happens in the real world".

He said tests also showed that the vaccines, which will soon go into use nationwide, did not protect ducks and geese as well as chickens, only providing protection for two or three months.

The source said the real challenge was finding an effective drug to vaccinate highly mobile water fowl, which are believed to be a reservoir of bird flu but do not usually display symptoms, and stop the spread of the virus in rivers and lakes.

The Harbin Veterinary Research Institute launched the vaccines mainly due to "market pressure", the source said. The institute, based in the capital of Heilongjiang province , was forced to come up with new products to help it reclaim some of the market share it lost last year after a challenge by rivals, the source said.
Moreover, Ron Nigh's perspective on the role of poultry vaccination in controlling bird flu puts a new light on this (see here, here and here).