New government data coming out of the International AIDS Conference in Washington today show only a quarter of Americans with HIV have the infection under control, and young people and blacks are least likely to get effective care.

The 25 per cent figure is slightly lower than previous estimates, and means more than 800,000 people aren't benefiting from life-saving drugs that also would lower their level of infection.

The Centers for Disease Control and Prevention says that's because nearly 20 per cent don't know they're infected, and only two-thirds who are diagnosed are linked to a doctor. It says poverty and lack of insurance are the main barriers.

Just 15 per cent of 25- to 34-year-olds have gotten the virus to low levels, less than half the rate of 50-somethings. And 1 in 5 African-Americans had the virus suppressed, compared with 30 per cent of whites.

The 19th International AIDS Conference in Washington, D.C., wraps up Friday.