A major study conducted in the United States, Europe and Australia has found that a popular AIDS drug roughly doubles the risk for heart attacks. The substance, abacavir, is one of three types of drugs used in combination to prevent the deadly HIV virus from replicating.

"This is a head-scratcher, in the sense that we don't really understand the biology here," said Paul Dalton, director of Treatment and Advocacy for Project Inform in San Francisco, as quoted by SF Chronicle.

Also, another AIDS drug was found to raise the risk of heart attack by 50 percent. The study was led by Jens D. Lundgren of the University of Copenhagen and analyzed data from more than 33,000 people infected with the AIDS virus who were followed for up to five years to see who had heart problems.

Those who took Ziagen, which is the brand name for abacavir, saw their risk increase double fold while those who took Videx, the brand name for didanosine, had their heart risk increased by half. Other anti-HIV drugs such as zidovudine (AZT), stavudine (Zerit) or lamivudine (Epivir) did not exhibit these side effects.

Top AIDS experts said in late March that a HIV vaccine will not be soon available and much more basic research is needed before attempting again to develop one. This conclusion was mainly the result of the total failure of trials for current vaccine prototypes, some of which have actually raised the risk of contracting HIV.

What the acknowledgement means is that no real progress was made in the past 25 years towards an effective AIDS vaccine. The announcement was made at a scientific meeting which took place at the National Institutes of Health in Bethesda. Dr. Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases, warned that there is no immediate solution for fighting against the deadly HIV.