GENEVA — New infections with HIV fell by one-third globally between 2001 and 2012, according to a United Nations report that shows the success of efforts to turn back the tide of the world’s deadliest infectious disease.

Worldwide, 2.3 million people were newly infected with the AIDS-causing virus last year, compared with 3.4 million in 2001, the Joint U.N. Programme on HIV/AIDS, or UNAIDS, wrote in a report released Monday. AIDS-related deaths fell 30% to 1.6 million last year from the peak in 2005, the Geneva-based agency said.

Investment in antiretroviral drugs increased to $18.9 billion last year compared with $3.8 billion in 2002. More than half of that comes from low- and middle-income countries.

“Today we have the tools we need to lay the groundwork to end the AIDS epidemic,” Michel Sidibe, UNAIDS’s executive director, said in the report.

Still, “in several countries that have experienced significant declines in new HIV infections, disturbing signs have emerged of increases in sexual risk behaviors among young people.”