Bird Flu: Antibodies From Survivors May Hold Clue to Remedy

An international team of scientists yesterday published evidence of a potential first step towards a treatment of the deadly H5N1 strain of avian flu which has claimed scores of lives around the world.

Their research successfully used antibodies from survivors of the Vietnamese strain of the disease to prevent it developing in mice, and to neutralize the virus in those already infected.

The H5N1 strain has killed millions of birds across the globe and by the middle of this month, according to the World Health Organization, there had been 306 known cases in humans, 185 of them fatal.

The results from the study, by scientists in Vietnam, Switzerland and the US, were published in the open access journal PLoS Medicine. Because of the international concerns about the disease, the work was fasttracked with funding from the Wellcome Trust in Britain, the National Institute of Health in the US and the Swiss National Science Foundation.

The researchers found the antibodies provided significant immunity to mice that were subsequently infected with the Vietnamese strain of H5N1. It also cut the amount of virus found in the lungs and almost completely prevented it from reaching the brain or spleen.

Cameron Simmons, a Wellcome Trust researcher at the Oxford University clinical research unit in Ho Chi Minh City, said: "We have shown that this technique can work to prevent and neutralise infection by the H5N1 bird flu virus in mice. We are optimistic that these antibodies, if delivered at the right time and at the right amount, could also provide a clinical benefit to humans with H5N1 infections."

He said researchers had found it was possible to administer the treatment up to 72 hours after infection. "This is particularly important as people who have become infected...do not tend to report to their local healthcare facilities until several days after the onset of illness," he said.

The antibodies were found in the laboratory of Antonio Lanzavecchia in Switzerland. Prof Lanzavecchia said although the research was encouraging it did not necessarily mean the antibodies would be useful in any future pandemic.

"Nevertheless, we are encouraged by the broad neutralizing activity of these antibodies in the lab and the moderate doses required," he said.

The technique has echoes of treatment during the 1918-19 Spanish H1N1 flu pandemic when physicians used blood taken from survivors to treat patients. A recent review suggested this treatment was associated with a halving in deaths caused by the virus.