World AIDS Day: See How Much Has Changed in the Fight Against HIV/AIDS

Researchers have made huge strides against the virus that causes AIDS.

— -- The virus that causes AIDS was identified less than 35 years ago but has left a lasting impact on hundreds of millions of people.

In honor of World AIDS Day, ABC News' medical unit has compiled important information to show how far the human race has come in the fight against HIV/AIDS and how much further the world needs to go.

“This epidemic has not gone away. It’s sort of the silent epidemic,” Corey said last month. “Worldwide, there are 2 million cases every year. Unfortunately, the disease is alive and well and thriving.”

Of the 1.2 million people in the U.S. with HIV, approximately 12 percent or 1 in 8 do not know they're infected.