Pandemic Fear of Fake Vaccines
Widespread use of ineffective and fake animal vaccines may be greatly increasing the threat of a human flu pandemic, a leading expert said yesterday.
Many vaccines given to poultry in bird flu hot-spots such as south-east Asia fail to control the virus, said Dr Robert Webster, from the World Health Organisation.
As a result, even in apparently healthy birds, the virus is allowed to spread and evolve into new forms.
With each new strain that develops, a new vaccine has to be designed to combat it.
In Asia, the potentially deadly H5N1 virus has already split into as many as five different lineages.
If one of these evolved into a variety capable of transmission between humans, or combined with an established human flu virus, it could spark a devastating pandemic claiming millions of lives.
Vaccines work by using an "antigen" - a protein from the target virus - to switch on an immune response.
Dr Webster, Director of the WHO Collaborating Centre for Studies on the Ecology of Influenza in Animals and Birds, said: "There are good vaccines and bad vaccines. Good vaccines reduce virus load; bad vaccines stop the signs of disease but the virus keeps replicating, spreading and evolving.
"The chickens look perfectly healthy but go on pumping out viruses for a long time.
"We have to ask the question, why are these animal influenza viruses showing so much antigenic drift? I would argue that contributing to this is the use of bad vaccines."
He said there was an urgent need for international standards to be applied to animal vaccines, as they are to those made for humans.
Britain led the world in achieving standardisation of human vaccines. Under the rules, flu vaccine must contain 15 milligrams of each of the three circulating strains of human virus, H1, H3 and B.
Animal vaccines should also have minimum amounts of antigen, said Dr Webster. …