More than half of the 9.5 million people who need AIDS drugs cannot get them and 33 million people across the world are still infected with the virus that causes it, a United Nations report said on Wednesday.

Access to drugs, counseling and testing for AIDS has increased, but there were still 2.7 million new infections in 2007 and the human immunodeficiency virus (HIV) that causes AIDS remains a major challenge for global health, it said.

Teguest Guerma, an AIDS director at the Geneva-based World Health Organization, noted some progress -- particularly in access to HIV testing and counseling, and getting HIV drugs to pregnant women and those in low- and middle-income countries.

But she said an internationally agreed goal of achieving universal access to treatment by 2010 was unlikely to be hit and required more concentrated effort.

We're moving toward universal access, but we're not there yet, she said in a telephone interview. We need to sustain the effort and commitment we have now to move forward.

Since the AIDS pandemic started in the early 1980s, more than 25 million people have died from the virus. There is no cure, but a cocktail of drugs known as highly active antiretroviral therapy can help keep it under control.

According to the UNAIDS report, groups at high risk of infection, including men who have sex with men, sex workers, drug users and prisoners, still have limited access to HIV testing and counseling services.

As a result, only 40 percent of all people estimated to have AIDS are aware that they are infected.

The report praised an unprecedented expansion of drug treatment in low- and middle-income countries, where more than 4 million people were receiving drugs by the end of 2008, up from around 3 million a year earlier.

The greatest gains were seen in sub-Saharan Africa, where around two-thirds of HIV infections occur. Around 2.9 million people there received treatment in 2008, compared with about 2.1 million in 2007.

Pregnant women, who can transmit the AIDS virus to their children, also had better access to tests and drugs. UNAIDS said 21 percent of pregnant women in low- and middle-income countries had an HIV test in 2008, up from 15 percent in 2007, and 45 percent of pregnant women with HIV got medicines.

Companies and non-profit groups, along with governments, have been working to make a vaccine against the virus that causes AIDS, and experts agree a vaccine is the only way to conquer it.

Trial results last week showed that for the first time, an experimental AIDS vaccine protected people from the virus -- but it only lowered the infection rate by 30 percent.

We need to continue the research because there is hope for the discovery of a vaccine, Guerma said. But for the time being, a vaccine with a modest efficacy cannot be used by itself.