US to test child bird flu vaccine

What may be the first clinical trial of a vaccine against the deadly strain of bird flu in children is set to take place in the US.

Scientists in St Louis want to test the vaccine, made from an inert form of the potentially lethal H5N1 virus, on 120 children aged between two and nine.

Centre for Clinical Vaccine Control experts say there is no risk and warn the young are more vulnerable to flu.

News of the trials emerged as the virus reached birds in Austria and Germany.

On Thursday, EU vets announced agreed to boost measures to prevent the spread of bird flu, increasing exclusion zones to 6.5m (10km) from one mile (1.6km) around affected areas, plus additional buffer zones.



Experts are working to develop a vaccine which could be used if a flu pandemic occurred.

It is believed the most likely way for this to happen would be if the H5N1 virus combined with a human flu.

The vaccine being tested in the US is made from a strain of the virus found in Vietnam.

It has already been tested by the National Institutes of Health on adults at clinical sites in the US.

Director of the centre in St Louis Dr Robert Belshe said it was crucial a vaccine was designed particularly for children as they are more susceptible to flu and have a different pattern of immune response to adults.

It is also thought that children are a key link in diseases spreading to pandemic proportions.

His team is currently recruiting for the study funded by the National Institute of Allergy and Infectious Diseases.


Stockpile?

Around 150 children die from influenza in the US each year so designing a vaccine that protects them will be a key step in the fight against any bird flu virus that might mutate to spread between humans.

Dr Belshe told the BBC there was no need to be concerned about the welfare of the children in the trial as any possible side-effects were very small and consisted of a sore arm and low grade fever that could be easily treated.

He said: "We are confident that what we are doing is safe and it yields a lot of information on how to give the bird flu vaccine should we need it."

The vaccine is grown in hens' eggs, with one egg per dose, and there are concerns that it may not be possible to create enough of it to treat all the youngsters that may be affected should a flu pandemic arise.


Professor John Oxford, a virology expert at Barts and the London Queen Mary's School of Medicine and Dentistry, said many pharmaceutical companies were trying to create an H5N1 vaccine.

"People are concentrating on this disease like never before."

He said there was disagreement among scientists about whether vaccines protecting against existing strains of the H5N1 virus should be created and stockpiled.

This is because many experts believe it would be better to wait and create a vaccine based on the exact type of virus that emerges in any future flu pandemic.

"I am in the group which things we should stockpile a vaccine and then modify it if and when a pandemic happens.

"It's seems to be sensible to try to go on what we have got now and indeed the government has already bought 2m doses H5N1 vaccine," he said.

Dr Jim Robertson, principal scientist at the UK's National Institute for Biological Standards and Control, said clinical trials of bird flu vaccines were being carried out around in the world, in China, Japan and Europe.

But he said he thought the US trial would be the first time a vaccine had been tested in children.