One of the scientists sharing the Nobel Prize in medicine for discovering HIV said Saturday he believes there will be a therapeutic vaccine to treat the virus within five years.

Luc Montagnier of France told reporters in Sweden that he believed it was "a matter of four to five years" before a therapeutic vaccine to treat HIV infection is developed. He did not elaborate as to why he believed scientists were close.

Scientists have developed lifesaving drugs that can inhibit the disease, but there is no vaccine to prevent or treat HIV infection. Finding a vaccine has proved elusive in the past, with the most recent trials ending in failure.,br> However, a therapeutic vaccine would be a key step in fighting the virus, he said. A therapeutic vaccine would be given to people who are already infected in order to lessen the impact of the disease, while a preventive vaccine would, ideally, protect people from HIV.

So far scientists have focused on drugs to fight the disease because they have been proving effective. In developed countries HIV has become manageable rather than fatal because of the drugs.

HIV was first identified 25 years ago, but still poses difficult challenges. Scientists cannot explain, for example, why it causes the immune system to collapse.

Montagnier and other Nobel laureates,began arriving in Stockholm on Saturday ahead of a week of Nobel festivities that culminate with a lavish banquet and awards ceremony December 10.

The 76-year-old scientist shares one half of the $1.2 million prize with 61-year-old Françoise Barré-Sinoussi, also of France, for their research on HIV. The other half goes to Germany's Harald zur Hausen, 72, for showing a viral cause for cervical cancer.

Sweden's King Carl XVI Gustaf will hand over the Nobel Prize in Physiology or Medicine on Wednesday along with the awards in chemistry, physics, literature, and economics. The Nobel Peace Prize is presented at a separate ceremony in Oslo, Norway.

[This report reprinted with permission of the Associated Press. (c) 2008 by Associated Press | December 6, 2008]