More than eight million people -- a record number in low- and middle-income countries -- are now taking antiretroviral drugs to treat HIV, according to data released Wednesday by UNAIDS.

The rise in drug coverage in 2011 was accompanied by a dramatic 31 percent drop in deaths from AIDS-related causes in sub-Saharan Africa, the area of the world most ravaged by the disease, compared to the peak of the epidemic in 2005.

In all low- and middle-income countries, the availability of antiretroviral drugs grew by more than 20 percent in just one year, over the latest figure of 6.6 million people covered in 2010, said the report.

Now, more than half (54 percent) of the estimated 14.8 million people in need of antiretrovirals in those countries can access them, according to the figures released in Washington ahead of the International AIDS Conference next week.

The report said the advance "puts the international community on track to reach the goal of 15 million people with HIV receiving treatment by 2015," an aim unanimously agreed by UN member states.

"But access (to treatment) is not universal. We still have a problem with access in Asia, in Eastern Europe, Central Asia so we need to redouble the effort," said UNAIDS Executive Director Michel Sidibe.

Those parts of the world are seeing deaths and new infections rise "in a very alarming way," he said.

More governments have stepped up funding to help those suffering within their own borders, with 81 countries increasing their domestic investments for AIDS by more than 50 percent between 2006 and 2011.

Overall, low- and middle- income countries invested $8.6 billion in responding to HIV/AIDS last year, an increase of 11 percent over 2010. International funding remained flat at 2008 levels of $8.2 billion.

Total worldwide investment in HIV totaled $16.8 billion last year, an 11 percent rise from 2010, but still far short of the $22-24 billion needed by 2015, the report said.

Nearly half (48 percent) of all international assistance for HIV response last year came from the United States, which is hosting the July 22-27 scientific meeting expected to draw 25,000 people.

US AIDS Coordinator Eric Goosby said reducing the impact of AIDS worldwide was a "priority" for the US government and called for nations to step up their involvement in local AIDS programs.

"If we do not aggressively move to work with our colleagues in country to expand their capacity to manage, oversee, monitor and evaluate these programs, regardless of resources we will fail," he said.

Reacting to the UNAIDS report, Doctors Without Borders also made a plea for faster pace in treatment and a boost in worldwide funding.

"Globally, we're finally past the half-way mark with HIV treatment, but that still means almost one in two people don't have access to the medicines they need to stay alive," said a statement by Eric Goemaere, the group's senior HIV/TB adviser in southern Africa.

"If we're going to reach all people who need treatment, we have to double the pace of scale-up and double the funds."

Other highlights of the UNAIDS report included the drop in the costs of antiretrovirals, from $10,000 per person in 2000 to less than $100 per person in 2011 for the least expensive WHO-recommended regimen.

Fewer children were infected with HIV in 2011 -- about 330,000 worldwide -- down 24 percent from 2009.

But a staggering 3.4 million children under 15 were living with HIV last year, 91 percent of them in sub-Saharan Africa.

The statistics were alarming for young women, too, with HIV named as the leading cause of death in women of reproductive age globally and those aged 15-24 facing infection rates that are double those of males the same age.

An estimated 1.2 million women and girls were newly infected with HIV last year, according to the report.

It also hailed studies showing that treatment with antiretrovirals could reduce the risk of transmission from an infected person to a healthy partner by 96 percent.

The report described a "significant reduction" in transmission to uninfected people who are at high risk through sexual activity and who take the drugs as a preventive measure, though it noted a "major challenge" in adhering to daily therapy.