K. Stark et al., FRONTLOADING - A RISK FACTOR FOR HIV AND HEPATITIS-C VIRUS-INFECTION AMONG INJECTING DRUG-USERS IN BERLIN, AIDS, 10(3), 1996, pp. 311-317
Objective: To determine whether frontloading (i.e., syringe-mediated d
rug-sharing) is a risk factor for HIV, hepatitis B virus (HBV) and hep
atitis C virus (HCV) infection among injecting drug users (IDU). Desig
n: Cross-sectional study. Data on sociodemographic and behavioural cha
racteristics were obtained by a standardized questionnaire. Serum samp
les were tested for seromarkers for HIV, HBV and HCV. Setting and part
icipants: IDU were recruited at 'low-threshold' storefront agencies (o
ut-of-treatment sample), and at a centre for long-term drug use treatm
ent (in-treatment sample). Individuals were included in the study if t
hey had injected drugs within the previous 3 months. Main outcome meas
ures: Serological evidence for HIV, HBV, HCV exposure. Results: Of all
IDU (n = 324), 84% had ever practised frontloading with non-sterile i
njecting equipment, and 46% had done so more than 100 times; 32% had f
rontloaded during the 6 months prior to the interview. The crude serop
revalence rates for HIV, HBV and HCV increased with the overall freque
ncy of frontloading, and reached 22, 71 and 94%, respectively, among I
DU who had frontloaded more than 100 times. After controlling for conf
ounding effects by logistic regression, having practised frontloading
more than 100 times was significantly associated with HIV infection [a
djusted prevalence odds ratio (POR) 3.5; 95% confidence interval (CI)I
1.4-9], and HCV infection (adjusted FOR, 5.4; 95% CI, 2.3-12), but no
t with HBV infection. Another independent risk factor for all three vi
rus infections was needle-sharing in prison. Conclusions: In communiti
es where sterile injection equipment is readily available, and IDU hav
e substantially reduced their overall levels of needle-sharing, the pr
actice of frontloading appears to be a major risk factor for infection
s by blood-borne viruses among IDU. Prevention activities should speci
fically address this risk behaviour.