It's one thing to tell people they're at risk for HIV. But if you can tell them the exact statistical risk that they'll get HIV in their lifetime, the message suddenly gets a lot more real. At least that's one of the assumptions behind a new, detailed breakdown of estimated lifetime HIV risk in the U.S. released on Feb. 23 by the U.S. Centers for Disease Control and Prevention (CDC).
The new numbers cast in sharp relief the extent to which HIV rates differ in the U.S. by race, sex and state. They range from a stunningly high lifetime risk of 1 in 2 for black men who have sex with men (MSM), to a relatively low risk of 1 in 883 for Asian women -- and from 1 in 13 for District of Columbia residents, to 1 in 670 for those who live in North Dakota.
The estimates, which were presented in an oral abstract presentation at CROI 2016 in Boston, are based on a combined analysis of reported HIV diagnoses from the National HIV Surveillance System, non-HIV death rates from the National Center for Health Statistics, and U.S. census data between 2009 and 2013. The analysis found that the overall HIV risk for people in the U.S. was now 1 in 99, a reduction from the 1-in-78 rate found in an earlier analysis of 2004-2005 data.
But that roughly 1% lifetime risk belies dramatic differences by subpopulation. A new fact sheet released by the CDC shortly after the CROI 2016 presentation highlights key research findings in bar graphs, showing comparative HIV diagnosis rates by transmission group:
Broken down by race and sex:
And broken down by individual U.S. state (including Washington, D.C.):
The fact sheet did not include all of the data points presented at CROI 2016, which identified the following lifetime HIV diagnosis risks among males:
- Males overall: 1 in 64
- Black males: 1 in 20
- Hispanic/Latino males: 1 in 48
- Native Hawaiian and Pacific Islander males: 1 in 82
- American Indian and Alaska Native males: 1 in 129
- White males: 1 in 132
- Asian males: 1 in 174
And the following lifetime HIV diagnosis risks among females:
- Females overall: 1 in 227
- Black females: 1 in 48
- Hispanic/Latino females: 1 in 227
- Native Hawaiian and Pacific Islander females: 1 in 385
- American Indian and Alaska Native females: 1 in 399
- White females: 1 in 880
- Asian females: 1 in 883
When assessing lifetime risk among males and females, the study did not account for transgender people, according to Kristen Hess, Ph.D., the lead author of the study who presented the data at CROI 2016.
Among MSM in particular, rates remained very high across racial/ethnic boundaries:
- MSM overall: 1 in 6
- Black MSM: 1 in 2
- Hispanic/Latino MSM: 1 in 4
- Native Hawaiian and Pacific Islander MSM: 1 in 7
- American Indian and Alaska Native MSM: 1 in 12
- White MSM: 1 in 11
- Asian MSM: 1 in 14
Although the study findings are not necessarily surprising in and of themselves -- the data have long shown which U.S. subpopulations are at higher risk for HIV -- this new depiction of lifetime risk "can more effectively communicate the level of risk and large disparities to the general public," Hess said. "This can be a useful tool for clinicians, outreach workers and policy workers."
At a press conference discussing the findings, Susan P. Buchbinder, M.D., of the University of California San Francisco concurred: "I think that what this points to is that we really need to be doing more aggressive programming and outreach to people who are in our most vulnerable populations," she said. "We do have very highly effective prevention, and we can change those numbers."
Buchbinder also spoke about the sex discrepancy in the lifetime risk for injection drug users. "Women are probably at risk both through sexual practices -- which may not be sex work, but could be survival sex -- but also because there are some studies that suggest that men go first when they're injecting and then the women get the injection equipment afterwards, so they're more likely to be infected that way as well," she said. "I think that there's always these issues of power dynamics in relationships."
The study authors noted some key limitations to the study findings, including the fact that HIV data focused on diagnoses (which are officially reported), not incidence, and thus would miss unreported infections. They also noted that the wide timespan of the data -- 2009 to 2013 -- assumed that there was no change in a person's risk trend during that period.
Myles Helfand is the editorial director of TheBody.com and TheBodyPRO.com.
Follow Myles on Twitter: @MylesatTheBody.