Update: Questions and Answers: Advances in Methods of Measuring HIV Incidence (CDC)

[pinto]

from the CDC, August 3, 2008. Some snips - pinto

Questions and Answers: Advances in Methods of Measuring Incidence

Why does there appear to be an annual increase in new HIV infections?

It is important to note that the new estimates do not show an increase in new HIV infections. The new estimates are from the first national surveillance system of its kind in the world that is based on direct measurement of new HIV infections using technology that can distinguish recent from long-standing, population-based infections.

Using the new surveillance system, CDC estimates that 56,300 new HIV infections occurred in the United States in 2006. CDC previously estimated that approximately 40,000 new HIV infections occurred annually since the 1990s. The 2006 incidence estimate is about 40% higher than the previous estimates. The new system reveals that the epidemic is—and has been—worse than previously estimated and underscores the need to expand HIV prevention to reach those at greatest risk.

Why is the new national HIV incidence estimate more precise and more reliable than prior estimates of HIV incidence?

CDC’s new HIV surveillance system is based on an approach known as STARHS (Serological Testing Algorithm for Recent HIV Seroconversion), which uses innovative testing technology to determine at the population level which positive HIV tests represent new HIV infections (those that occurred within approximately the past five months).

Before the widespread availability of this technology, HIV diagnosis data provided the best indication of recent trends in key populations. However, diagnosis data only indicate when a person is diagnosed with HIV, not when an individual was actually infected, which can occur many years before a diagnosis.

By applying this technology to new HIV diagnoses in 22 states with mature name-based HIV reporting systems, CDC was – for the first time – able to identify those diagnoses in a given year that represented new infections. Using a complex statistical model, these data were extrapolated to the general population to provide the first national estimates of HIV incidence based on direct measurement.

Which populations experienced the greatest burden of HIV infections in 2006?

The 2006 HIV incidence estimates show:

Gay and bisexual men of all races remain the group most heavily affected by HIV, accounting for 53% of all new infections.

The impact of HIV is greater among blacks than any other racial or ethnic group, with an HIV incidence rate that is 7 times higher than whites (83.7/100,000 for blacks compared to 11.5/100,000 for whites) and almost 3 times higher than Latinos (29.3/100,000).

Will CDC be looking at new interventions and communication strategies to prevent HIV among populations hardest hit by the epidemic?

Yes, CDC is currently working to expand the use of new scientifically proven interventions for a range of populations at risk and testing a number of innovative behavioral interventions for key risk groups, particularly African American men who have sex with men (MSM). CDC remains committed to expanding HIV prevention and care services to all at-risk populations and those hardest hit by the epidemic, such as African Americans and MSM. It is clear that there is an urgent need to accelerate progress, and as a nation we must continue to invest in prevention and extend the reach of HIV prevention services.

Last Modified: August 3, 2008
Last Reviewed: August 3, 2008

Content Source:
Divisions of HIV/AIDS Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention

http://www.cdc.gov/hiv/topics/surveillance/resources/qa/incidence.htm