Bird flu flares anew, raising uneasy questions

By Tan Ee Lyn

HONG KONG (Reuters) - The re-emergence of birdflu in Asia and Egypt has prompted experts to ask tough questions: are poultry vaccines effective against a virus that is constantly mutating, and are governments doing enough to stop it spreading?

The virus turned up last week in a farm equipped with modern biosecurity measures in Hong Kong, killing over 100 chickens and leading to the culling of some 80,000 birds there, in nearby farms and a wholesale market.

Now Guan Yi, an expert on the H5N1 virus at the University of Hong Kong, has warned that poultry farms in some parts of the world were using vaccines that didn't provide full protection against the H5N1 and can't keep up with its mutations.

"That vaccine (used in Hong Kong) was made to fight an American strain of the H5N2, and it is very distant from the Guangdong strain of the H5N1 virus here," he said.

"When there were no outbreaks, we just assumed it was protective. Now that there is an outbreak (in the Hong Kong farm), we assume it is useless," he said in an interview.

While the use of human vaccines is overseen by the World Health Organisation, supervision over the use of veterinary vaccines is far more lax.

"For human vaccines we have recommendations by the WHO. For veterinary vaccines there is no such thing at this moment," said Albert Osterhaus, a leading virologist at the Erasmus Medical Center in Rotterdam.

"There is a quality issue and there have been lower quality vaccines seen in the past.