June 27, 2006

Scientists warn against mass poultry vaccination

Scientists are now warning that mass vaccination of domestic poultry may make it more difficult for health workers to detect the deadly H5N1 strain of bird flu.

Some countries have used mass vaccination as a way to calm consumers' fears about the safety of poultry, however, mass vaccination could also disguise the H5N1 that manages to survive in innoculated flocks.

So far, the EU has resisted mass vaccination of its poultry, preferring to limit vaccinations to areas where bird flu outbreaks have occurred.

The European Centre for Disease Prevention and Control (CDPC) said that mass vaccination, when imperfectly carried out like those in China and Indonesia, may impede detection of further cases.

Detection of human cases of bird flu may become harder in these cases as the marker of local poultry deaths is being lost, the CDPC stated in a report.

A total of 57 countries around the world have so far reported detecting the H5N1 bird flu, either in wild birds or domestic poultry.

Bird flu has killed 64 percent of those people known to be infected with the virus this year, according to World Health Organization statistics. There were 217 cases of infection and 123 deaths worldwide. Most of the deaths occurred in Asia.

The H5N1 virus is considered firmly entrenched in poultry throughout much of Indonesia, and this widespread presence of the virus has resulted in a significant number of human cases.

This year, Indonesia reported more than 33 cases with 27 deaths.