HIV resists drugs

Jul 27, 2003

One in ten people who test positive for HIV in Europe is infected with a virus that is already resistant to drugs, suggests a Europe-wide survey

By Charles Wendo and agencies

One in ten people who test positive for HIV in Europe is infected with a virus that is already resistant to drugs, suggests a Europe-wide survey.

Europe’s resistance levels are now akin to those in the United States. “This limits the number of drugs available to treat these patients from the beginning,” says Joep Lange, director of the International Antiviral Therapy Evaluation Centre in Amsterdam, Holland. “It could have been predicted,” says Lange. Researchers from 19 European countries tested 1,633 newly infected patients for drug resistance. They presented their findings during a conference that the International AIDS Society meeting in Paris, France, between July 13 and 16 2003.

Dr. Peter Mugyenyi, who was in the audience when the study was presented in Paris, says it serves as an alarm bell for Africa, which will be the biggest user of anti-retroviral drugs in future. He said resistance is most prevalent in Europe and America because those regions have used anti-retrovirals for longer periods, and on much larger numbers of patients.

Mugyenyi, Director of the Joint Clinical Reasearch Centre in Kampala, said they have detected less than 50 out of more than 10,000 patients in Uganda with drug-resistant HIV strains, but said the number will definitely grow as more people access the drugs. These are on anti-retroviral drugs.

Resistance develops faster when patients take the wrong doses or swallow the pills irregularly, allowing the virus to survive and adapt. Resistant viruses are thought to be less infectious, but they can be passed on to someone else.

However, even with the most correct treatment, resistance inevitably occurs to any drug meant to kill germs, especially with life-long treatment such as anti-retroviral therapy.

“There is no method known to science, that can completely prevent drug resistance from occurring,” Mugyenyi said.

The European study highlights serious problems in the management of anti-HIV drug use, says virologist Richard Tedder of University College London. Too many patients do not or cannot comply with their treatment regimen, or are being prescribed drugs to which they are likely to become resistant, he reckons. “Some clinics are breeding grounds for new resistance,” he says.

But the results could be an overestimate, Tedder adds. HIV mutates so rapidly that people are infected with a “swarm” of different varieties, he says. This makes it difficult to know whether a resistance mutation that shows up in a test will actually cause problems once the patient begins drug treatment.

Another reason cited for rapid spread of resistance in Europe and America is that for a long time they were using a single drug, AZT.

Scientifically it is known that resistance takes longer to develop when one uses a combination of drugs. But in the late 1980s and early 1990s when AZT was the only anti-retroviral drug, the world had no choice.

Mugyenyi said that although anti-retroviral resistance in Uganda at the moment is only a tiny percentage (less than 50 out of more than 10,000 patients), it is going to grow in future. It doesn’t mean Ugandan patients are more responsible than Europeans in using the drugs. It’s only because the drug has not yet been used here on a large scale.

He forecasted that in the next five to 10 years, Africa will become the biggest user of anti-retroviral drugs since the region has the biggest number of people with HIV, and the drug prices are reducing.Uganda, he said, is already the biggest user of anti-retroviral drugs in Africa. Therefore resistance will inevitably increase as anti-retrovirals become widely used. “We need to plan ahead how to deal with resistance,” he said.

Experts at the meeting called for new ideas on how to manage resistance. “The single most important factor is adherence to drug therapy,” says HIV-resistance specialist Deenan Pillay, also of University College London.

Mugyenyi said JCRC had acquired hi-tech facilities for monitoring drug resistance, and intends to work with the Uganda Virus Research Institute to monitor anti-retroviral resistance countrywide. At the same time he advised people to get treatment only from doctors who have been specifically trained on anti-retroviral therapy.

He also advised patients to always adhere to the treatment advice given by their doctors

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