Boston ? The HIV infection rate among blacks in the United States has doubled over a decade while holding steady among whites — stark evidence of a widening racial gap in the epidemic, government scientists said Friday.

Other troubling statistics indicate almost half of all infected people in the United States who should be receiving HIV drugs are not getting them.

The findings were released in Boston at the 12th Annual Retrovirus Conference, the world’s chief scientific gathering on the disease.

“It’s incredibly disappointing,” said Terje Anderson, director of the National Association of People With AIDS. “We just have a burgeoning epidemic in the African American community that is not being dealt with effectively.”

Researchers and AIDS prevention advocates attributed the high rate among blacks to such factors as drug addiction, poverty and poor access to health care.

The HIV rates were derived from the widely used National Health and Nutrition Examinations Surveys, which analyze a representative sample of U.S. households and contain the most complete HIV data in the country. Researchers at the Centers for Disease Control and Prevention compared 1988-1994 data with figures from 1999-2002.

Still, they show a striking rise in the prevalence of the AIDS virus from 1 percent to 2 percent of blacks. White rates held steady at 0.2 percent.

Largely because of the increase among blacks, the overall U.S. rate rose slightly from 0.3 percent to 0.4 percent.