Bird flu researchers warn of vaccine delay
24 October 2005, RIEMS, GERMANY - German animal-health experts warned Saturday that an improved vaccine to protect poultry against bird flu is nowhere near the production stage, despite the westward spread of the H5N1 virus.
24 October 2005
RIEMS, GERMANY - German animal-health experts warned Saturday that an improved vaccine to protect poultry against bird flu is nowhere near the production stage, despite the westward spread of the H5N1 virus.
The vaccine, under development on the Baltic Sea island of Riems where Germany studies the deadliest animal diseases, solves the main problem with existing vaccines by including a genetic marker to distinguish the vaccine virus from the virus in the wild.
Using existing vaccines, it is almost impossible to map the spread of the disease, since a vaccinated bird and an infected bird give the same test result. Healthy, vaccinated poultry have to be slaughtered and burned too if the H5 virus reaches a farm.
Thomas C. Mettenleiter, head of the Friedrich Loeffler Institute on Riems, said the prototype vaccine, which has a marking system built into it, had been successfully tested, but it faces a long path to regulatory approval and manufacture.
The institute is to meet with vaccine makers next week to review whether more research is needed and how to apply for the approval.
Alarm is growing round the world at the spread of the highly pathogenic strain H5N1, which can spread to people. It has killed 60 persons so far in Asia.
Mettenleiter said the vaccine uses a weakened avian herpes virus modified by a gene from avian influenza. It can be applied to poultry as a spray or in their drinking water. Birds can still catch H5, but show few symptoms and are less likely to pass it on to other birds.
He noted that northern Italy had used the existing vaccines against the H5 and H7 subtypes of avian influenza for the past five years with poor results. The disease had continued in the area, and some birds had had to be left unvaccinated for checking purposes.
The scientist said the current vaccine was not suitable for long- term prevention, but only to stop an outbreak going out of control. Afterwards, all vaccinated birds had to be considered as potentially infected and slaughtered anyway.
Subject: German news