Date: Thu, 2 Mar 1995 08:59:46 -0500 From: New York Newsday - Thursday, March 2, 1995 On The Threshold Of An AIDS Disaster by Gabriel Rotello New York - In some ways it's the most hopeful study about gay men and AIDS prevention I've read in years. In other ways it's the most terrifying. I'm still trying to decide which. The study is called "Effect of Sexual Behavior Change on Long-term HIV Prevalence among Homosexual Men." Its authors are Martina Morris and Laura Dean, two researchers at Columbia University's School of Public Health who have spent years tracking the AIDS epidemic. Last year they set out to predict its future path among local gay men. Morris and Dean report that in the years before the epidemic, gay male New Yorkers had an average of about 11 "unsafe contacts" per year, an "unsafe contact" being a person with whom one has unprotected sex at least once. By 1991, after years of education and behavior change, gay men had reduced that number to just one per year. Morris and Dean tried to figure out whether that was enough to lower HIV transmission below the epidemic threshold. Epidemic threshold is the point at which the average infected person infects precisely one other person. Anything above that point and an epidemic will relentlessly grow. Anything below it, and the epidemic will shrink and eventually die out. Using models that have proven remarkably accurate in predicting the epidemic so far, Morris and Dean spun out the next 35 years based on the 1991 average of one unsafe contact per year. At that level, transmission among gay men lies just below the epidemic threshold. As the years go by the percentage of gay men infected with HIV slowly drops from around 40 percent today to a mere five percent in 2030. To me, this is the most important, hopeful finding in AIDS prevention in years. It means that at 1991 levels of safer sex, gay New Yorkers had succeeded in prevention's fundamental goal. Even without a cure or a vaccine, even if we just continued what we were doing in 1991, future gay generations would be spared the devastation that engulfed my generation in the 1980s and 1990s. That's the good news. The bad news is that Morris and Dean created a second model to predict what would happen if gay men slipped just a little bit in the direction of unsafe sex. Their second model assumed that gay men had returned to a level of two "unsafe contacts" per year instead of one, a fairly plausible assumption considering that the original number back in 1981 was eleven. That small difference - between one unsafe partner and two per year - produces disaster. Transmission rises well above the epidemic threshold in every age category. The charts flow upward instead of down as the years roll by, and instead of a 5% level of infection in 35 years, gay men over 40 have a 65% level of infection. In other words, the difference between one unsafe contact and two is the difference between an almost AIDS-free future and absolute catastrophe. There are two powerful messages here. One is that it is indeed possible for gay men to eliminate the epidemic through behavior change alone. In New York we even know precisely what level of safer sex is necessary to get us there. We know because we lived that level back in 1991. But the other message is how little it would take to push us over the threshold. And how enormous the consequences would be if that happened. "The implications of even temporary returns to unsafe practices are not simply an increase in individual risk," warn Morris and Dean, "but also the persistence of HIV transmission at epidemic levels in the [gay] population." Where are we today? The last time anybody checked, levels of unsafe sex were rising among gay men in almost every study. But Morris and Dean can't really say what the figures are. Their funding has run out.