Leading article: A welcome glimmer of hope

And it is getting worse. The virus is cutting a swath through the African continent. And in Russia and China it is spreading rapidly. Around 40 million people around the world are believed to be infected. It has become a global pandemic.

And no vaccine for the virus has yet been developed. A decade ago, scientists created a cocktail of drugs to curtail its effects. These antiretroviral drugs work by reducing the level of HIV virus in the blood. This has changed Aids from being something that kills the patient very quickly, to a chronic disease which the sufferer can live with, like diabetes. But it is no cure.

The new method of treatment being developed in the United States has shown some encouraging results. While existing retroviral drugs bring the HIV virus levels down, Dr David Margolis and his colleagues in North Carolina have discovered that combining them with an existing drug - valproic acid - appears to perform this even more effectively. In a test of this treatment on four Aids patients, three registered a 75 per cent reduction in latent HIV infection.

Naturally, there must be caution. This new treatment needs further development. And it is vital to bear in mind that any treatment regime is useless unless those suffering from the disease have access to it. Scandalously, this is what is happening with the present generation of antiretroviral drugs. The epidemic is at its worst in South Africa, Namibia and Zambia. Yet the drugs fail to reach millions in these countries.

They are still prohibitively expensive for the poor, despite the fact that the cost of treatment has come down from £6,000 a year to £180. The rich nations of the world are still not providing enough resources to finance the United Nations' global anti-HIV fund at the rate of $20m (£11m) a year. This is what is required simply to prevent the epidemic from getting worse.

There is a now a glimmer of hope that Aids can be defeated. Resources should be urgently directed towards testing and developing this new treatment. But this should not distract the international community from its moral duty to ensure that everyone in the world suffering from this deadly virus has access to those life-preserving drugs that already exist.