The Institute of Fisheries Management has released a position statement on KHV which advises against stocking with vaccinated carp.
The IFM statement recommends that fishery managers do not accept vaccinated fish as a method of reducing the risk of Koi Herpes Virus.
It said: "The technology used to develop this vaccine is unproven, and there is a risk that the live viruses in the vaccine will revert back to a full pathogenic Koi Herpesvirus.
"The vaccine is also unlikely to confer protection on the fish longer than six months, making it inadequate long term protection.""Tests for KHV are not fully able to distinguish between vaccinated fish and previously infected fish."At present diagnostic tests for KHV are not fully able to distinguish between vaccinated fish and previously infected fish.
The IFM said that until tests can differentiate between carriers and vaccinated stock, and "the question of latency has been satisfactorily answered" a precautionary principle should be adopted.
It advises fisheries not to stock vaccinated fish.
Vaccinated carpSpeaking at the recent Ornamental Aquatic Trade Association (OATA) conference, fisheries management consultant Dr Bruno Broughton told delegates that many anglers were blaming vaccinated fish on this year's KHV outbreak.
"The first that most people would have heard of KHV was when this year, when consent was sought and eventually granted to import KHV-vaccinated carp from northern Israel for introduction into UK fisheries."
Broughton said he was not implying a direct link between the introduction of vaccinated fish but said that major KHV outbreaks started this summer, with 23 cases record in the year so far.
CEFAS said that of these 23 cases only two had received vaccinated fish.
When asked whether he thought it was possible for vaccinated carp to infect naiive fish with KHV, Dr Peter Dixon of CEFAS told delegates:
"It would depend on what type of vaccine was being used. The main cause of concern at the moment is with the live attenuated virus. This is the basis of the Israeli vaccine.
"If the next generation of the vaccine is tagged then that will help matters, to allay peoples' fears. If there are outbreaks subsequent to the introduction of vaccinated fish we may then be able to differentiate between vaccinated fish that will be great."
Last year, scientists from Israel claimed that the attenuated vaccine for KHV was safe.