Half of gay and bisexual black men and a quarter of gay and bisexual Hispanic men will be diagnosed with HIV in their lifetimes, the Centers for Disease Control announced in a first-of-its-kind study on Tuesday.

While the lifetime risk of a positive HIV diagnosis has fallen from 1 in 78 Americans overall in 2005 to 1 in 99 today, the decline has not been distributed equally among the U.S. population. For the foreseeable future, the CDC estimates that gay, bisexual, black and Hispanic people will continue to bear the brunt of the HIV epidemic. The new study is the first time that the CDC has estimated lifetime HIV risk based on race.

Overall, the CDC projected that one in 64 men and one in 227 women in the United States will be diagnosed with HIV at current rates. For black and Hispanic people, however, that risk increases dramatically.

Regardless of sexual orientation, one in 20 black men and one in 48 black women will be diagnosed with the virus that causes AIDS in their lifetimes, according to the CDC. For Hispanic men and women, the risks are one in 48 and one in 227, respectively.

White people have the lowest chance of an HIV diagnosis, with an overall lifetime risk of less than one percent. Gay and bisexual white men still have a lifetime risk of one in 11, though.

The CDC’s projections are based on data about HIV diagnoses and death rates collected from 2009 to 2013, and they assume that rates of new diagnoses remain constant. If that’s the case, one in six men who have sex with other men will be diagnosed with HIV in their lifetimes.

“These estimates are a sobering reminder that gay and bisexual men face an unacceptably high risk for HIV—and of the urgent need for action,” said Dr. Eugene McCray, director of the CDC’s Division of HIV/AIDS Prevention. “If we work to ensure that every American has access to the prevention tools we know work, we can avoid the outcomes projected in this study.”

For Hispanic people living in the United States, the CDC has already outlined an array of factors behind the alarming rate of new infections: a high prevalence of HIV, poverty and lack of health insurance coverage, “machismo” that can encourage men to engage in risky sexual behavior as a show of strength, and reluctance to access prevention services for fear of revealing one’s immigration status.

In South Florida, for example, an already high prevalence of HIV has combined with low awareness of the virus and social stigma to produce the highest rate of new infections in the U.S., driven largely by new infections among young Hispanic men.

For black people, CDC resources show, prevention challenges are similar: poverty, stigma, barriers to health care access, and too few people knowing their status. Risk in black communities is especially high, the CDC notes, because “African Americans tend to have sex with partners of the same race/ethnicity mean[ing] that [they] face a greater risk of HIV infection with each new sexual encounter.”

According to the CDC’s new projections, all of the states with the highest lifetime risk for HIV are in the South, with the exceptions of New York, New Jersey, Delaware, and the District of Columbia. All of these states and the South tend to have large black and Hispanic populations, higher rates of poverty, and less health-insurance coverage.

The CDC estimates that HIV risk is highest in Maryland, Georgia, Louisiana, and Florida, with about 2 percent of these states’ populations believed to test HIV positive eventually.

No single area may be worst-hit than Washington, D.C., which is nearly 50 percent black and 10 percent Latino. According to the CDC’s projections, a staggering one in 13 D.C. residents will be diagnosed with HIV in their lifetimes.

But the CDC doesn’t want its projections to be interpreted as a death sentence.

“As alarming as these lifetime risk estimates are, they are not a foregone conclusion. They are a call to action,” said Dr. Jonathan Mermin, director of the CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and Tuberculosis Prevention.

If the U.S. can reduce new infections, those lifetime risk numbers will go down, too. The CDC’s current prevention approach emphasizes HIV testing, condom use, treatment for those who have already been diagnosed, and pre-exposure prophylaxis (PrEP), a daily medication that has been shown to reduce risk by more than 90 percent when used correctly.

“The prevention and care strategies we have at our disposal today provide a promising outlook for future reductions of HIV infections and disparities in the U.S.,” said Dr. Mermin, “but hundreds of thousands of people will be diagnosed in their lifetime if we don’t scale up efforts now.”