Despite increasing evidence suggesting that drug addicts have compromised immunity, vigorous discussion continues. One way to examine this clinically is to compare the rates of infections presenting to a clinic which sees both non-substance dependent (N-SUD) and opiate addicted (SUD) patients.

A survey was conducted amongst our patients of all infectious presentations.

Four-hundred and thirty SUD and 116 N-SUD patients of similar ages (mean±SD 30.81±7.77years vs. 32.91±14.41 respectively) were reviewed. SUD had fewer acute infections (120/430, 28% vs. 51/116 44%, OR=0.60 95% CI 0.40–0.84, P=0.0034) but their severity was greater (P<0.00001). The pattern of infections was also different with respiratory infections predominating in N-SUD (32/50 infections, 64%; seasonally invariant) vs. dental (74/114, 64%) and skin infections (18/114, 16%) in SUD. SUD had significantly more dental infections (74/430 patients 21% vs. 3/116 3%, P=0.0001). In multivariate analysis, group membership was the only variable which explained the variance of “Infection”. Chronic hepatitis C (60% vs. 1%, P<0.00001) was more frequent in the SUD but there was no difference in hepatitis B or HIV.

These data are consistent with clinical immunosuppression in SUD and may reflect immunostimulation and immunosenescence.