Leading article: Progress and peril

Two pieces of rare good news have emerged from the 18th International Aids conference being held in Vienna. First, the number of young people infected with HIV has fallen by a quarter in 12 of the 25 worst affected countries in the world, and is on a downward trend in four others, as the prevention message about safe sex appears to be getting through. Second, women have for the first time the prospect of acquiring a means of protecting themselves with the development of a vaginal gel that cuts the HIV infection rate by over 50 per cent.

After 25 years in which scientists have struggled to contain the spread of Aids, searching for a vaccine or cure, or means to alter sexual lifestyles, these are important gains. They show that the battle against the virus has not been in vain. But it is far from being won. And there are fears that the developed world is losing its appetite for the fight at a critical stage. The number living with HIV is not declining but rising, thanks to the life-saving effects of antiretroviral drugs. There were 33.4 million people living with HIV worldwide in 2008, of whom 2.7 million became infected that year and two million died.

Despite the investment of billions of dollars over the last decade, only five million of the 15 million people who need antiretroviral treatment are currently receiving it. Aids has a worse impact than other diseases – which carry off the elderly – because it strikes in the prime of life, damaging economies and creating a generation of orphans. Although progress has been made on developing a vaccine, researchers in Thailand last year claimed "proof of concept" with a prototype providing 30 per cent protection, it will not provide an answer in the foreseeable future. Action must come on multiple fronts: boosting the supply of antiretroviral drugs, increasing access to male circumcision (which cuts infections by 60 per cent), preventing mother-to-child transmission and spreading the safe sex message.

The world economic crisis has put the future funding of Aids programmes in doubt. Critics complain that Aids programmes swallow a disproportionate amount of the development cash available for health and that funds should be diverted to other diseases. The future of The Global Fund to Fight Aids, Tuberculosis and Malaria, one of the two principal sources of Aids cash, is uncertain.

The world's most vulnerable citizens already receive pitifully little help to preserve their health. The benchmark should be set by how much we give to Aids, not how little we give to other conditions. Cutting back now would be unconscionable.