Hepatitis B Virus (HBV) Serological Status among People Who Enter the Opioid Substitution Programme in Greece

Author: Anagnostou O., Kanavou E., Fotiou A., Andaraki A., Richardson C., Kafetzopoulos E., and Terzidou M., Medical Doctors Group of OKANA

Theme: Epidemiology & Public Health Research Year: 2016


Anagnostou O.,1 Kanavou E.,2 Fotiou A.,2 Andaraki A.,2 Richardson C.,3 Kafetzopoulos E.,1 and Terzidou M.,2 Medical Doctors Group of OKANA1

1Greek Organisation Against Drugs (OKANA), Athens, Greece

2Greek Reitox Focal Point of the EMCDDA, Athens University Mental Health Research Institute (UMHRI), Athens, Greece

3Panteion University of Social and Political Sciences, Athens, Greece

Background: Substance users are at high risk for HBV infection. Although vaccination is recommended to substance users, little is known regarding incidence of susceptibility and correlates of HBV serological status in this population.

Methods: Anonymous bio-behavioural data were collected from 805 people who entered opioid substitution treatment in central and southern Greece in 2013. Three mutually exclusive groups were defined according to the HBV serological markers: natural contact [(HBsAg(±)/AntiHBc(+)/antiHBs(±)], vaccination history [HBsAg(-) /antiHBs(+)/antiHBc(-)] and HBV susceptibility [HBsAg(-)/antiHBs(-)/antiHBc(-)]. Multinomial logistic regression analyses identified differences between groups according to socio-demographic, drug use and higher-risk behavioural characteristics.

Results: Of those with complete serological data (N=706; 38.2 years mean age, 80.3% males, 95.4% of Greek origin), past natural contact was observed in 39.0% (N=275), vaccination history in 24.1% (N=170) and susceptibility in 37.0% (N=261). Multivariable analyses indicated that the risk of not being vaccinated (i.e., HBV susceptibility and natural contact) was higher in those aged >44 years (relative risk ratio [RRR]=2.9, 95% confidence interval [CI]: 1.0-8.6, p=0.050 for susceptible and RRR=3.9, 95% CI: 1.2-12.4, p=0.020 for natural contact) and with≥15 years of drug use history (RRR=1.8, 95% CI:1.1-2.8, p=0.016 for susceptible and RRR=2.3, 95% CI: 1.4-3.8, p=0.001 for natural contact). Those tested antiHCV(+) showed negative association with susceptibility (RRR=0.6, 95% CI: 0.4-0.9, p=0.014), but positive association with natural contact (RRR=5.1, 95% CI: 2.8-9.3, p<0.001). Other risk factors for natural contact but not HBV susceptibility included male gender (RRR=2.1, 95% CI: 1.2-3.6, p=0.011) and no history of previous treatment for addiction (RRR=2.3, 95% CI: 1.3-4.0, p=0.005). Conclusion: Despite the long-standing availability of anti-HBV vaccination a large proportion of drug users are still susceptible to the infection. Vaccination should be offered at addiction treatment centers especially focusing to those at high risk for HBV susceptibility (i.e., older drug users with long history of drug use). Disclosure of Interest Statement: Nothing to disclose

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