Vaccine against lethal strain of avian flu ready for human testing

[Angel]

A British drug company is seeking permission to conduct the first human trials of an experimental vaccine against the avian flu virus.

The vaccine will target the lethal H5N1 strain of avian flu, which has spread rapidly throughout bird populations in Asia and has been brought to Europe by flocks of migrating waterfowl. The World Health Organisation has reported 97 human cases of avian flu since December 2003, with at least 53 deaths.

Health officials fear the virus could mutate into a form easily transmissible between humans, potentially triggering a pandemic to rival Spanish flu in 1918, when an estimated 40m people died.

Plans for the trial have been submitted to the UK Medicines and Healthcare Products Regulatory Agency, which is expected to give the green light for the trial to proceed at a London hospital.

A vaccine against avian flu could significantly bolster efforts to limit the infection's spread if a pandemic strain emerges, by adding to government stockpiles of the anti-viral drugs Tamiflu and Relenza.

Unlike conventional vaccines, which use weakened strains or fragments of the harmful virus, the test vaccine uses strands of DNA that can be made quickly and cheaply.

In the trial, volunteers will be vaccinated using an alternative to a needle. Instead, a handheld device will blast harmless, microscopic gold particles coated in the vaccine into the upper arm at supersonic speeds.

Tests of a DNA vaccine designed to give protection against seasonal flu were published earlier this year and showed that it offered 100% protection, based on the immune response of volunteers.

So far, the DNA vaccine against avian flu has only been tested in animals, where it has also proved successful.

"Our tests have shown that it stops the infection entirely, to the point that we can't even measure the virus in the animals afterwards," said John Beadle, chief medical officer of the Oxford-based company PowderMed.

The company's research suggests humans would need two doses of the vaccine, a prime and a boost. Calculations suggest that less than half a kilogram of DNA would be enough to offer two doses of the vaccine to everyone in Britain.

The company has listed details of the trial on the government's website, Clinicaltrials.gov where it states it is seeking 75 volunteers for the trial at Guy's drug research unit in London.

If the trial goes ahead as planned, volunteers will be tested over several months to monitor how long the vaccine remains effective. Preliminary results are expected in January next year.