A United Nations agency says that since 2001, the rate of new HIV infections has been cut in half, in 25 low- to middle-income countries, a majority of them in Africa.
The findings are in an annual report released Tuesday by the Joint United Nations Program on HIV/AIDS known as UNAIDS.
UNAIDS also says AIDS-related deaths in sub-Saharan Africa have dropped by one-third over the last six years while the Caribbean region has experienced a 48-percent reduction in deaths for the same period.
UNAIDS chief analyst Peter Ghys says a number of factors have contributed to the drop in HIV rates and AIDS deaths, including increased awareness about how the disease is spread.
"For reductions in new infections in adults, that has also happened over the past decade, the programs that have brought about changes in incidents are programs that address changes in behavior. So, we have seen in a number of countries, changes towards safer behaviors," Ghys said.
Progress, however, in the fight against AIDS has been uneven.
UNAIDS researchers say the number of people newly infected with HIV has risen more than 35 percent in the Middle East and North Africa since 2001.
The group also says the infection rate has climbed in Eastern Europe and Central Asia.
Ghys says a lack of programs to combat drug abuse has contributed to the rise in HIV infections in some regions, including Eastern Europe.
"A lot of the transmissions there are among intravenous drug users and so some of the key countries in that region actually are not, or are not yet, implementing the right policies, policies to reduce transmissions in that situation," Ghys said.
The group says some African countries which have had the highest prevalence of HIV cases in the world have seen significant drops in infection rates since 2001. The group says the rate has fallen 73 percent in Malawi, 71 percent in Botswana and 68 percent in Namibia.
UNAIDS says about $16.8 billion in funding was available globally in 2011 to fight the spread of AIDS. The group estimates as much as $24 billion will be needed by 2015.
UNAIDS says in 2011, an estimated 34 million people worldwide were living with HIV and 1.7 million died from AIDS-related illnesses.
Some information for this report provided by AP and Reuters.