WASHINGTON (Reuters) - About one-half of one percent of young adults living in homes in the United States are infected with the AIDS virus, around 600,000 people, the National Center for Health Statistics reported on Tuesday.

The agency’s snapshot of HIV infection in the United States shows the rate continues to be stable and confirms other surveys that show black men are far more likely than other Americans to be infected.

The report covers adults aged 18 to 49 and only people living in households -- not prisoners, the homeless or patients in institutions, said Gerry McQuillan, who led the study.

The data comes from people taking part in the federal government’s National Health and Nutrition Examination Survey, who volunteer to have their blood tested for everything from cholesterol to AIDS and herpes, as well as undergo full physical exams.

“What we have done is taken data from our surveys in 1999 to 2006 because HIV has a very low prevalence. You have to combine all the years,” Gerry McQuillan, who led the study, said in a telephone interview.

“In 1999 to 2006, the prevalence of HIV infection among adults aged 18-49 years in the civilian noninstitutionalized household population of the United States was 0.47 percent,” the report reads.

That works out to anywhere between 447,000 people and 841,000 people, with 618,000 the middle number, McQuillan said.

Men were more likely to be infected (0.7 percent) than women (0.2 percent). People infected with the herpes simplex type 2 virus, known as genital herpes, were 15 times more likely to also be infected with HIV, according to the report, availablehere.

Black men aged 40 to 49 had the highest rate of infection, at close to 4 percent, the survey found.

The National Center for Health Statistics, part of the U.S. Centers for Disease Control and Prevention, included 11,928 adults in the survey. These numbers can be extrapolated to the full population.

“We do see the disparities by race/ethnicity,” McQuillan said. “We can say the prevalence is basically stable in this U.S., household-based population.”

The report does not include data on how many people are newly infected with HIV.

These numbers have not been released but AIDS advocacy groups say the new figures will put the number of Americans infected with the AIDS virus each year close to 50 percent higher than previous estimates, at 55,000 instead of 40,000.

The CDC has estimated in the past that more than 1 million Americans in total are infected with the human immunodeficiency virus that causes AIDS.

Globally, 33 million people are infected and 25 million have died from the fatal and incurable virus.