Good, Bad HIV News About Injection Drug Users

Fewer injection drugs users are infected with HIV, but they're also less likely to have been tested for the virus, according to CDC data.

Interviews and tests in 2009 by the agency's National HIV Behavioral Surveillance System showed that 9% of that year's new infections occurred among injection drug users, the CDC reported in the March 2 issue of Morbidity and Mortality Weekly Report.

That's down from 12% the last time the system surveyed drug users in 2006.

In 2009, investigators interviewed and tested 10,073 injection drug users in 20 metropolitan statistical areas across the U.S. and found that - of the 9,565 whose HIV status was negative or unknown before the survey - only 49% reported being tested within the previous year.

That is also down from 2006, when 66.3% reported being tested.

Another change for the worse was that just 19% of the 2009 participants reported taking part in a behavioral intervention aimed at reducing their risk of HIV - down from 29.7% in 2006.

The surveillance system, established in 2003, is intended to assess trends in HIV risk behaviors, testing, and HIV prevention services among injection drug users, men who have sex with men, and heterosexuals.

The data are collected about once every three years from each of the three groups.

For this survey, participants were asked a series of questions about their behavior in the previous year, including whether they had shared syringes or other equipment, had vaginal sex either protected or unprotected, had heterosexual anal sex protected or unprotected, had been tested for HIV, and had taken part in an HIV behavioral intervention.

Of the participants who were tested, 9% were positive and 45% of those who were HIV-infected had not known of their infection previously.

The researchers also found that:

69% reported having unprotected vaginal sex, up slightly from 63.4% in 2006.
34% reported sharing syringes, also up marginally from the 32.8% in 2006.
23% reported having unprotected heterosexual anal sex during the 12 previous months. The equivalent 2006 data weren't reported.
The results "highlight the need for expanded HIV testing and prevention" among injection rug users, the CDC argued.

The agency cautioned that some participants might not have accurately reported their behavior to interviewers, leading to a social desirability bias.

As well, the participants were interviewed in regions with a high AIDS prevalence, so that the findings might not apply to other cities or states, the CDC noted.

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Primary source: Morbidity and Mortality Weekly Report
Source reference: Centers for Disease Control and Prevention "HIV infection and HIV-associated behaviors among injecting drug users - 20 cities, United States, 2009" MMWR 2012; 61: 133-138.