Luc Montagnier, one of two scientists receiving the Nobel Prize in medicine this week for discovering HIV, believes there will be a therapeutic vaccine to treat HIV infection within the next few years, The Associated Press reports.

Montagnier told reporters December 6 in Sweden that it may be “a matter of four to five years” before a vaccine is developed. He did not elaborate as to why he believed a vaccine was within reach.

While antiretroviral medications have proved effective, the search for a vaccine has been unsuccessful, with several recent trials ending in failure.

However, Montagnier affirmed that a vaccine would be an essential step in fighting HIV. A therapeutic vaccine could treat people who have HIV and a preventative vaccine could prevent transmission.