Methadone maintenance treatment and HIV type 1 seroconversion among injecting drug users

When HIV-1 seroconversion status among prospectively followed methadone maintenance clients was analyzed by treatment retention, 1/56 (2%) of those who remained continuously in treatment seroconverted while 8/42 (19%) of those whose methadone treatment was interrupted seroconverted. When controlled for length of follow up, the difference in seroconversion rate was not statistically significant. Subjects in continuous treatment had a seroconversion rate of 0.7 per 100 person years (95% Confidence Interval [Cl] = 0.1, 5.3) and those with interrupted treatment a rate of 4.3 per 100 person years (95% Cl =2.2, 8.6). Subjects in continuous treatment reported less needle sharing (p < 0.0002), fewer needle sharing partners (p < 0.002), fewer sexual partners (p < 0.03), and were more likely to be women (p < 0.01). These data indicate the need for larger studies to evaluate both client and drug treatment program characteristics which might concomitantly increase treatment retention and decrease HIV-1 risk. This study examined whether methadone maintenance treatment decreases drug injection enough to significantly limit HIV-1 transmission among injection drug users (IDU).