Does Poz Diagnosis Influence Behavior?

Seeking to amend the state law governing HIV testing, Dr. Thomas R. Frieden, the city’s health commissioner, has said that eliminating the requirement for written consent in favor of one dependent on documented verbal consent will get more people tested and that those who know they are HIV-positive will reduce their unsafe sex.

Similarly, the federal Centers for Disease Control and Prevention (CDC), which is poised to recommend routine HIV testing for Americans aged 13 to 64, has put out two recent studies—one showing decreases in unsafe sex after people test positive and a second that predicted a decrease in new infections from sex if people learn they are HIV-positive.

Now some researchers are saying that there are good reasons for people to get tested, but testing and its associated counseling alone will not change the course of the AIDS epidemic.

“There’s very good evidence that a lot of people when they first test positive… do rather radically change their behavior, but there is also compelling data that it doesn’t last very long,” said Dr. Seth C. Kalichman, a psychology professor at the University of Connecticut.

While a positive HIV test “is a sufficient intervention for a majority of people… it isn’t for a significant minority,” Kalichman said.

The group that does not change its behavior is large enough to keep the epidemic thriving since they are having unsafe sex with uninfected partners, he said.

“We would estimate that at any given time somewhere between 20 and 30 percent are engaging in unprotected sex with partners who could be infected,” Kalichman said. “That significant minority is definitely driving some infections.”

The first CDC study, a “meta-analysis” of 11 studies or data sets, concluded that, on average, unsafe anal or vaginal sex was 53 percent lower in people who knew they were positive versus people who did not know their status. Those changes are sustained, said Dr. Richard Wolitski, chief of the CDC’s Prevention Research Branch.

“I feel that we have pretty good data to address that issue,” he said. “For persons with HIV there seems to be stability or a slight reduction over time.”

In the second study, the CDC cited the meta-analysis and used mathematical modeling to promise a 31 percent drop in new infections attributed to sex if “all people unaware of their infection could learn of their serostatus.”

The meta-analysis has become part of the discussion over changing the state law governing written consent.

In a written statement, Dr. Adam Karpati, the city health department’s acting assistant commissioner for HIV Prevention and Control, said, “Knowing your HIV status is a key factor in reducing risky behavior. On average people who test positive reduce risky behavior by about half. Diagnosing all persons with HIV infection through routine HIV testing is critical to reducing HIV-related illness and death in New York City.”

In a 2005 interview with New York magazine, Frieden said, “Knowledge is power. Most people who know their status… do the right thing. So increasing the proportion of people who know their status is probably the single most important thing we can do to reduce the spread of HIV.”

Other studies paint a different picture and suggest that the promise that HIV testing will result in dramatic changes in the AIDS epidemic is overstated because a positive test does not always change behavior.

A 2005 study of 140 gay and bisexual men in Florida found high rates of unsafe sex in that population. Thirty-one percent of the men were HIV-positive, but the reports of unsafe anal sex among all the men “were not associated with HIV antibody status.” Drug use, disliking condoms, having unprotected oral sex, and having a primary partner were factors that predicted unsafe anal sex in the study.

“That sort of flies in the face of what everybody else has been reporting, particularly CDC,” said William W. Darrow, a professor of public health at Florida International University and one of the study’s authors. “I think it’s false to assume that just because somebody finds out they are HIV-positive they are going to stop doing what they were doing for the past 20 years of their sexual lives.”

A 2002 study by San Francisco’s health department of 66 recently-infected gay men, which was used in the CDC’s meta-analysis, did report an initial decline in risky behaviors after the men learned their status. Over 12 months, however, the unsafe sex increased.

Two of the other studies, one from 1991 and the other from 1988, used in the meta-analysis reached a similar conclusion. While they found reductions in unsafe sex, those were not attributed to a positive HIV test. The men and women in those studies who had high-risk sex after testing positive had had high-risk sex before testing positive.

“That’s one of the truisms,” Kalichman said. “Past behavior is the best predictor of future behavior.”

Other data show unambiguously that HIV-positive people who know they are infected and are in treatment are contributing to new infections.

A July article by the city health department that ran in the CDC’s Morbidity and Mortality Weekly Report noted that the federal agency had funded four cities and 17 state health departments to test newly-diagnosed people for resistance to anti-HIV drugs.

“Provisional data” showed that 15 percent were infected “with an HIV strain that has mutations associated with resistance” and 3.2 percent “have mutations associated with resistance to two or more classes of such medications.” That data demonstrated that these newly-diagnosed people were infected by people already in treatment.

Even some who have documented the reductions in unsafe sex that result from a positive diagnosis dispute that testing alone will change the epidemic.

“It has to be combined with mental health referrals, substance abuse treatment, STD treatment, and programs in the community to promote safe sex,” said Dr. Thomas J. Coates, director of the global health program at UCLA. “People like to think of simple, easy operational strategies and that’s just not the nature of prevention.”

Coates just completed a study of 2,000 men and women in East Africa that showed that those who tested HIV-positive “changed their behavior substantially” up to a year later.

Routine testing in doctor’s offices and hospitals will not capture groups that do not visit these places, such as young black and Latino men who have sex with men, Coates said.

“If we routinize HIV testing those are exactly the people who don’t access medical services,” he said.

For Kalichman, the emphasis on testing is indicative of the abandonment of serious HIV prevention efforts.

“What’s been missing is getting people into prevention counseling,” he said. “What really has been lacking in the public health infrastructure is a serious commitment to behavioral intervention with people in post-test counseling.”