Less than a third of people infected with HIV have the potentially deadly virus under control, a new study says.

Just three in 10 Americans diagnosed with HIV, which can lead to AIDS, are keeping the virus in check with medication, according to the report published Tuesday by the Centers for Disease Control and Prevention. Two-thirds of those infected, with the virus out of control, were not receiving medical care, it said.

In the United States, more than 1 million people have HIV, with 50,000 new infections every year.

"For people living with HIV, it's not just about knowing you're infected, it's also about going to the doctor for medical care," said Dr. Tom Frieden, director of the CDC. "Key to controlling the nation's HIV epidemic is helping people with HIV get connected to and stay in care and treatment to suppress the virus, live longer and protect others."

Antiviral drugs keep patients alive and stem transmission of the virus. But many people, who can live for years without symptoms, don't even know they're infected.

In Oregon, an estimated 1,000 people are infected but don't know it, while about 6,100 people have been diagnosed, said Dr. Sean Schafer, public health physician and medical epidemiologist with the state's HIV, STD and TB program.

He said the state is doing well in terms of providing treatment to those who are infected, thanks to money from the Ryan White fund, a federal program named after the boy who was diagnosed at 13 and died at 18. The program supports about 3,000 people with HIV in Oregon, often paying their health care premiums so that they can keep the virus in check.

Not all states leveraged money from the fund, which is distributed nationally, toward health care costs for people with HIV. Tyler TerMeer, executive director of the Cascade AIDS Project, said that was a smart thing to do.

"Individuals who have regular ongoing access to care and adhere to their medications and have a suppressed virus are 96 percent less likely to transmit the virus," TerMeer said.

New infections in Oregon have been going down as a result, Schafer said, with 240 people newly diagnosed in 2011 and about 200 in 2012. He expects a 20 percent drop in 2013 when those figures come in.

"The dismal picture you get from the federal government is tempered substantially in Oregon," Schafer said.

The CDC report found that younger people were more likely to not be getting care for the virus. Only 13 percent of those between 18 and 24 had the virus in check, with treatment rates gradually ramping up to 37 percent for those 65 and older.

"It's alarming that fewer than half of HIV-positive young adults know they are infected," said Dr. Eugene McCray, head of the CDC's Division of HIV/AIDS Prevention. "Closing that gap could have a huge impact on controlling HIV."

TerMeer said the problem is not just medical but social.

"There continues to be stigma and isolation that acts as a barrier for individuals for entering care," TerMeer said. "That's coupled with discrimination, homophobia and transphobia and the fear of criminalization for exposing their status."

Schafer acknowledged that fear is a problem, but he said HIV is not what it used to be 20 years ago. The Life expectancy is nearly equivalent to someone who doesn't have HIV, provided they're diagnosed early and treated.

Public health officials recommend that those who are at risk be tested frequently, especially sexually active adults who have had sex without a condom, along with pregnant women, anyone who has shared a needle or who has a sexually transmitted disease. All adults, regardless of their lifestyle, should be tested at least once in their lifetimes, Schafer said.

Tests are confidential, quick and inexpensive. For more information, check Cascade AIDS Project testing page.

-- Lynne Terry