Upon learning they are HIV positive, gay men initially reduce higher risk sex with HIV-negative partners and those of unknown HIV status, but they return to it within one year, according to a study published online December 15 in the Journal of Acquired Immune Deficiency Syndromes. The data further indicate that methamphetamine use remains a powerful influence on sexual risk taking and that knowledge about HIV status and viral load are not influencing sexual decision making in ways that experts hoped it would.

Public health officials have taken a number of actions in recent years to help stem the tide of HIV infections, particularly in the United States and Europe. On the one hand, authorities have put significant resources toward promoting early and regular HIV testing. Previous studies have suggested that people who know their HIV status will reduce behaviors that pass on HIV to others.

On the other hand, health authorities in Europe, primarily, have taken a different approach, issuing statements that people with undetectable levels of HIV are far less likely to infect others and that people who know their viral load are able to make better choices about sex. Few studies have been conducted, however, in recently infected men who have sex with men (MSM) to test these assumptions.

To determine the sex behaviors of this population group, Pamina Gorbach, PhD, of the University of California in Los Angeles, and her colleagues followed 193 MSM who recently contracted HIV. Most of the men were followed for one year, between 2002 and 2006, with surveys conducted at the beginning of the study and every three months thereafter.

The average age of the study participants was 35, and most were either white or Latino. Partner status was mixed. About one third had a steady partner throughout the course of the study; one third remained single throughout the study, and one third went in and out of a relationship during that time.

Gorbach and her colleagues noted that the men changed their sexual behavior after learning they were positive. The average number of partners reported in the month before each survey decreased from 8.81 at the start of the study to 5.84 one year later. Also, the number of men predominantly practicing unprotected anal intercourse (UAI) with other HIV-positive men—a risk reduction method known as serosorting—increased from 15 percent to 39 percent.

While the percentage of men reporting recent UAI with partners of unknown HIV status initially dropped from 49 percent to 27 percent over the first nine months of the study, it climbed substantially (to 71 percent) by the end of the year.

More than 90 percent of the men had regular viral load testing through the course of the study and were aware of their viral load. They did not, however, report varying their sex partners or sex behavior based on having an undetectable viral load.

Overall, methamphetamine (meth) use was one of the strongest predictors of continued UAI with HIV-negative partners and partners of unknown serostatus. Meth use remained high throughout the study, though the percent reporting meth use with their most recent partner dropped from an exceptionally high 29 percent at the beginning of the study to a still concerning level of 10 percent one year later.

“Our findings highlight the importance of the first six months after diagnosis as a time when behavior change occurs. It also suggests a need for programs to support the maintenance of such changes after this window of opportunity and particularly after nine months of follow-up,” state the authors.

“The finding that the percent reporting UAI did not diminish significantly over time among methamphetamine users was not surprising,” the authors continue, “but lends support to the urgent need to develop better access to, higher treatment adoption, and more effective substance use treatment for those with HIV.”