Resistance to Aids drugs is growing, say scientists

The Aids virus is becoming increasingly resistant to the drugs used to treat it, researchers said yesterday.

The Aids virus is becoming increasingly resistant to the drugs used to treat it, researchers said yesterday.

Scientists surveyed HIV- positive patients in Europe who had never taken retroviral drugs. One in 10 had a resistance to at least one of them.

The study, led by scientists at the University of Utrecht in the Netherlands, involved 1,633 HIV patients from 17 European countries diagnosed between 1996 and 2000. It found that 9.6 per cent of newly diagnosed HIV patients in Europe were infected with a virus that was resistant to at least one drug. About 2 per cent had an infection that did not respond to two or more types of Aids drugs.

Scientists had known that the virus could become resistant to drugs, and that resistant strains could be spread, but until now the extent of that transmission was not clear.

The findings, presented at the conference of the International Aids Society in Paris, showed that the resistance appeared to be attributable to HIV-positive patients who were taking the medication infecting others with a drug-resistant strain. The research team, lead by Dr Charles Boucher, said that if these strains of HIV continued to spread, drugs used to treat the virus would be limited.

One of the researchers, David van de Vijver, said that patients infected with strain B, the most common strain in Europe and North America, were four times more likely to get a resistant infection than those who contracted other varieties of HIV.

The research team recommend that patients diagnosed with HIV who became infected in Europe be tested to see if they had a drug-resistant strain.

Experts said that some level of resistance would probably continue. But Dr Joep Lange, president of the International Aids Society, estimated that the rate of resistance would be about 2 per cent if people started on a good triple drug combination and took their drugs properly. He said: "For people who have difficulty adhering, make sure they have support mechanisms to help them."

Dr Peter Piot , the executive director of UNaids, the UN programme to combat HIV/ Aids, said that resistance served as a warning that the delivery of drugs in poor countries needed to be organised carefully. "It reminds us that when we introduce antiretroviral therapy we've got to do it well," he said, adding that a universally followed standard prescription for initial treatment should be part of the strategy.

Kevin Frost, director of Treat Asia, a programme of the American Foundation for Aids Research, said the results showed that the world was at a crucial point with Aids treatment. He said: "We are in a somewhat volatile period right now and the therapeutic anarchy that is going on - we have to get a handle on it. Doctors have the freedom, especially in the West, to prescribe whatever they want. There are 19 drugs approved in the United States now with 21 or 22 formulations ... it means there are hundreds, if not thousands, of potential combinations."

He said that in developing countries, doctors were forced to prescribe the "drugs they could get". But he said that what they could get was often not what they should be prescribing. "We have to take our best shot first," he said. "If we use the right regimens and we use them correctly, we can minimise the opportunities for the development of resistance. If we don't get it right, we could be in for serious problems long-term in developing countries."