CDC Publishes Detailed Analysis Of HIV Spread In US

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Main Category: HIV / AIDS
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Article Date: 12 Sep 2008 - 1:00 PDT

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The US Centers for Disease Control and Prevention (CDC) has published a detailed analysis of HIV spread in the US following last month's revelation that the HIV epidemic is, and has been, worse than previously known, because the estimated number of new infections in 2006 was found to be about 56,300, which is 40 per cent higher than the 40,000 they thought it would be.

The new analysis is published in the CDC's Morbidity and Mortality Weekly Report (MMWR, September 12, 2008) and gives a more detailed picture of HIV incidence in specific US populations. A summary fact sheet was also published on 11th September, to coincide with a press briefing.

The new estimate of HIV infections in 2006 confirmed that the most heavily affected groups were gay and bisexual men of all races, African Americans, and Latinos, said the CDC.

It also shows, said the agency in its press briefing, "that, within these groups, the impact is most severe among young black gay and bisexual men, white gay and bisexual men in their 30s and 40s, and black women".

The more detailed analysis shows, for example, more detailed breakdown by age of infection rates among gay and bisexual men (or commonly in these analyses abbreviated to MSM, for men who have sex with men):

• There were more new HIV infections in young black MSM (13-29 year olds) than any other age/racial group of MSM. The number of new infections among young black MSM was about double that of whites and of Hispanics (5,220 infections in blacks compared to 3,330 in whites and 2,300 in Hispanics).


• White MSM came to nearly half (46 per cent) of HIV incidence in 2006. Most new infections among white MSM occurred in 30-39 year olds (4,670), followed by 40-49 year olds (3,740).


• Among Hispanic MSM, most new HIV infections were in the youngest age group (2,300 among 13-29 year olds), followed by a not inconsiderable number among the 30-39 year olds (1,870).

The new analysis also gives more detail on the impact of HIV among men and women in different racial groups. It may help to understand why African Americans, who represent only 12 percent of the total US population, represented 45 percent of new HIV infections in the United States in 2006. For example:

• Black women are far more affected by HIV than women of other races: 15 times higher incidence rate than white women and nearly 4 times higher than Hispanic women (55.7 per 100,000 population among black women compared with 3.8 among white women and 14.4 among Hispanic women).


• The HIV incidence rate for black men was about 6 times higher than for white men and nearly 3 times higher than for Hispanic men (115.7 per 100,000 in black men compared with 19.6 among white men and 43.1 among Hispanic men). Among black men, the majority of new infections (63 per cent) was among MSM.

The CDC suggests that the disproportionate rates of HIV infection among African Americans in the United States could be due to higher HIV prevalence among African Americans, poverty, stigma, limited access to health care, greater use of drugs, and higher rates of other sexually transmitted diseases.

"Many black women face additional challenges, such as power imbalances with men in sexual relationships," wrote the CDC.

The new analysis shows that Latinos are also disproportionately affected by HIV, because they contributed an estimated 18 per cent of new infections in 2006, and yet they only represent 15 per cent of the total US population. Within the Latino HIV infections, men accounted for over three quarters of new infection in 2006 (76 per cent), and 72 per cent of the infections among men were in MSM.

The infection rate among Hispanic men was more than twice that of white men (43.1 compared to 19.6 per 100,000). Hispanic women, who represented just under a quarter of new infections among Hispanics in 2006, had an infection rate that was nearly 4 times that of white women (14.4 compared to 3.8 per 100,000).

The CDC wrote that many of the issues that put African Americans at higher risk of HIV also affect Latinos, but Latinos also face unique challenges such as language barriers and cultural values that may stop them acknowledging risky behaviour (machismo). There may also be higher risk due to the fact some Latinos born outside the US experience long term separation from partners left behind and find new partners in the US.

While these results show there are considerable challenges to fighting HIV, the CDC said there is also significant evidence that prevention works, especially when "we apply what we know". So far, precision campaigning has helped to impact particular groups, and resulted in reduction in HIV rates among heterosexuals, injection-drug users, and due to mother-to-child transmission of HIV, which has shown the most dramatic results.

But more effort is needed, said the agency, to accelerate progress in HIV prevention, and this will require a collective response. The agency is focusing its efforts in 4 key areas:

• Expanding HIV testing services to reach the 25 per cent of HIV-infected people whom the agency estimates don't realize they are infected.


• Ensuring that proven HIV prevention programs exist, are accessible to those who need them, and delivered by workers trained in prevention methods.


• Developing new approaches to HIV prevention through research.


• Improving surveillance systems to the best possible population data on HIV.

"Subpopulation Estimates From the HIV Incidence Surveillance System."
US Centers for Disease Control and Prevention.
MMWR, September 12, 2008 / Vol. 57 / No. 36.

Click here to view the CDC report.

Source: CDC.

Written by: Catharine Paddock, PhD
Copyright: Medical News Today
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