In advance of World AIDS Day the US Centers for Disease Control and Prevention (CDC) released its latest report on recently diagnosed HIV infections in the United States. The new HIV Surveillance Report, which covers data to the end of 2015, shows that HIV diagnoses have decreased among both women and men, and among African Americans, Latinos and white people, but have risen among young people age 25-29. As people with HIV live longer thanks to effective antiretroviral treatment, HIV prevalence has reached an all-time high of more than 955,000 people.
CDC's HIV Surveillance Report, which has been published since 1982, includes detailed information about diagnosed HIV infection in the US. This year's edition uses a new approach – made possible by improvements in surveillance methods and data sources – that will no longer involve statistical adjustment to account for delays in reporting.
"Our nation’s HIV surveillance systems have advanced a long way since the early days of the epidemic, both in terms of how data is collected and how it is analysed and reported. Today, most states report complete information on HIV cases to CDC - including the person’s age, race/ethnicity, risk factors and even their HIV viral load at the time they are diagnosed," explained Eugene McCray, director of CDC's Division of HIV/AIDS Prevention. "Removing duplicate cases takes much less time than it used to, and new technology means we can process large quantities of data much more quickly."
While the new report includes 2015 data, assessments of trends are based on HIV diagnoses and deaths from 2010 to 2014. The CDC cautioned that data for 2015 are considered preliminary, based on only a six-month reporting delay, and may not include all recently diagnosed cases. Although the 2015 data are not included in the trends, they do provide minimum estimates of the number of new diagnoses and a preliminary 'snapshot' of how they're distributed across different groups.
Rates of new HIV diagnoses in 2015 (per 100,000 people)
- Men: 24.4
- Women: 5.4
- American Indian/Alaska Native: 8.8
- Asian: 5.5
- Black/African-American: 44.3
- Hispanic/Latino: 16.4
- Native Hawaiian/Pacific Islander: 14.1
- White: 5.3
- Multiple/Mixed Race: 12.2
- Northeast: 11.6
- Midwest: 7.6
- South: 16.8
- West: 9.8
Men who have sex with men had the highest number of new diagnoses in 2015 – more than 26,000 – compared to about 3000 people who acquired HIV via heterosexual contact and 1400 via injected drug use. Among women, heterosexual contact accounted for nearly 6400 cases and injection drug use for 980 cases. However, the CDC did not calculate rates for transmission categories due to uncertainty about the denominators, or the total number of gay/bisexual men or people who inject drugs in the population.
Key trends from 2010 to 2014
The annual numbers and rates of HIV diagnoses decreased overall, and among both men and women. Diagnosis rates decreased among African Americans, Latinos, Native Hawaiians/Pacific Islanders and white people, while American Indians/Alaska Natives and Asians saw an increase. Rates decreased in all four geographic regions of the US.
HIV diagnosis rates increased among people age 25-29, remained stable among those age 20-24 and decreased in all other age groups. The 25-29 age group had the highest diagnosis rate, as well as being the only one that increased.
The number of diagnoses attributed to male-to-male sexual contact remained stable, while the number attributed to heterosexual contact or injection drug use decreased. Again, CDC did not calculate transmission category rates due to missing denominators.
The annual number and rate of people diagnosed with stage 3 HIV disease, or AIDS, decreased overall; rates or numbers declined for men and women, and for all age groups, racial/ethnic groups and transmission categories.
The number and rate of deaths due to any cause among people diagnosed with HIV also declined. Decreases were seen for both men and women and for most racial/ethnic groups and transmission categories. Death rates decreased for all age groups under 54, remained stable for people aged 55-59, and rose for people age 60 and older.
The number and rate of people living with diagnosed HIV infection increased; at the end of 2014 total prevalence reached 955,081 – the highest number to date. African Americans accounted for 42% of people with diagnosed HIV, despite making up about 13% of the total US population. Men who have sex with men accounted for about 70% of both total and newly diagnosed HIV cases.
People aged 50-54 made up the largest proportion (18%) of people living with diagnosed HIV at the end of 2014, and the greatest increase was seen in the 65 and older age group, reflecting the ageing of the epidemic.
The CDC noted that trends in new HIV diagnoses are influenced by testing rates. If more tests are done, more people will test HIV-positive even if the actual rate of new infections – known as incidence – has not changed.
Nevertheless, "the declines seen in this report suggest that national HIV prevention efforts are paying off, while signalling the urgent need for intensified prevention among young people and men who have sex with men," according to McCray.
"One encouraging sign is that HIV prevalence – the number of people living with diagnosed HIV – reached an all-time high at the end of 2014, largely because fewer people are dying of HIV than ever before," McCray wrote. "This signals that our efforts to improve care outcomes are having a positive impact. It is also encouraging because we know that when people’s HIV is suppressed by treatment, they are unlikely to transmit infection to others."
Centers for Disease Control and Prevention. Diagnoses of HIV Infection in the United States and Dependent Areas, 2015. HIV Surveillance Reports, vol 27, 2016.