New combinations of protease inhibitors now offer great hope to those with HIV, but the total number of people infected with virus that is resistant to this drug regimen will climb as use of the treatment increases, the model shows. And, as the treatment becomes more widespread, some clinicians and patients are likely to be less rigorous with treatment protocol, the researchers predict. Finally, as gay people come to believe that control of the disease is possible, high-risk sexual behavior among some may increase. Otherwise, the promise of controlling AIDS will vanish. But we must and can turn epidemiology into a predictive science.
Tuberculosis offers a sobering example.
Some three million people worldwide die every year from the TB bacterium. Her research team developed a model to anticipate the effect of this strategy. About 22 percent of Americans are afflicted with these contagious genital lesions, with numbers well above 40 percent in some inner cities. Only about five percent of Americans seek treatment, but Blower and her colleagues found that unlike the problem with TB, the mutation rate and other traits of herpes allows an aggressive treatment program without generating a dangerous number of drug-resistant cases. The purpose of the models is to determine when treatment will be effective in controlling epidemics, and when it may cause more harm than good.