DAKAR, May 28 (Xinhua) -- Jean-Francois Delfraissy, director of France's National Agency for Research on AIDS and Viral Hepatitis (ANRS), here has ruled out any hope of developing a vaccine to fight HIV/AIDS in the short term, according to reliable sources.

    "The development of a preventive or therapeutic vaccine against HIV has still a long way to go and is certainly one of the most difficult challenges facing the world's scientific community today," Delfraissy told reporters in the Senegalese capital of Dakar on Tuesday.

    The professor, who teaches clinical immunology and internal medicine at the Faculty of Medicine Paris-Sud, is also one of the pioneers of the fight against AIDS in France, according to reliable sources.

    "Since the first ever vaccine trial was launched, over 80 phases I and II have been conducted mostly in Europe and the United States and one clinical trial has even gone as far as phase III, but without much success being recorded," said Delfraissy.

    "A series of quarantine tests are under study and among them is a vaccine that the ANRS has been developing under the past ten years," according to the French researcher who called for increased efforts against the disease.

    "Clinical research must continue to develop new therapeutic strategies within the framework of trials that should be conducted in accordance with good clinical practices, dialogue and partnership with the civil society and the pharmaceutical industry," said Delfraissy.

    "We must continue to move forward in our search for a better understanding of immune mechanisms, improve available vaccine candidates, assess their tolerance and immunogenicity using clinical trials," said the professor.