The European Journal of Public Health Advance Access originally published online on August 10, 2005
The European Journal of Public Health 2005 15(5):464-466; doi:10.1093/eurpub/cki145
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Infectious Diseases |
Prevalence of hepatitis A among drug users in north-eastern Italy
Is vaccination necessary in low prevalence areas?
Fabio Lugoboni1, Gianluca Quaglio1, Benedetta Pajusco1, Maurizio Foroni2, Gianstefano Blengio2, Giorgio Talamini3, Paolo Mezzelani1 and Don C. Des Jarlais4
1 Medical Service for Addictive Disorders, Department of Internal Medicine, University of Verona, Italy
2 Department of Hygiene and Public Health, ASL 22 Villafranca, Verona, Italy
3 Department of Internal Medicine, University of Verona, Italy
4 Edmond de Rothschild Chemical Dependency Institute, Beth Israel Medical Center, New York, NY, USA
Correspondence: Fabio Lugoboni MD, Medical Service for Addictive Disorders, University of Verona, Policlinico GB Rossi, 37134 Verona, Italy, e-mail: paolo.mezzelani{at}univr.it
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Abstract |
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Background: The authors report on the prevalence of, and risk factors for, hepatitis A virus (HAV) in a group of drug users in Italy. Methods: 404 heroin users were recruited and compared with a control group of 107 subjects in the general population. Results: Drug users born in north-eastern Italy have a prevalence of anti-HAV similar to the control group. A much higher prevalence was found in drug users born in southern Italy. Conclusion: The similar prevalence of anti-HAV in drug users born in north-eastern Italy and in the general population, suggests that their lifestyle does not involve a substantial additional risk of HAV. The much higher prevalence found in drug users born in southern Italy is more likely to be related to infection during infancy.
Keywords: HAV infection, heroin users, HAV vaccination
Infection with hepatitis A virus (HAV) causes an acute infection of the liver. The infection is usually self limiting, but typically produces fever, malaise, anorexia, nausea and abdominal discomfort. The severity of disease and mortality increases in older age groups. Complications of HAV infection can include fulminant hepatitis, cholestatic hepatitis and relapsing hepatitis.1 HAV infection is highly correlated with poor social and economic conditions. Oral-faecal is the most common mode of transmission, with parenteral [shared needles among drug users (DUs), transfusions, contaminated drug solutions], sexual (especially anal) and vertical transmission occurring less frequently.1–3 Hepatitis A can also be potentially spread among DUs by contamination from rectally carried drugs.4,5 The seropositive rates in this population is significantly higher than in a matched control population.6–9 Because persons who use illicit psychoactive drugs are at increased risk for HAV infection, there have been multiple recommendations for HAV vaccination for DUs.1–3,6–10
Italy has low to intermediate endemic levels of hepatitis A, with frequent outbreaks of epidemics in the south, where HAV antibody prevalence levels are greater than in the north.11–13
In this paper, we report on the prevalence of, and risk factors for, HAV antibody in DUs and in the general population in the Veneto region of Italy.
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Methods |
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Between January 1997 and December 2000, 404 heroin users were recruited. All were voluntarily in care at a Public Health Authority Centre for Drug Users (PHCDU) in the Veneto Region, and all resided in the province of Verona. These publicly funded PHCDUs provide counselling, treatment for drug withdrawal, short-term detoxification with low-dose methadone, methadone maintenance programmes, psychotherapy and so on. Moreover, these centres deal with medical problems related to addiction such as vaccination against HAV, HBV, HIV testing, etc.14 The data collected for each patient were: age, sex, duration of drug use and place of birth. The patients were categorized into three groups for place of birth: (i) those born in the province of Verona, (ii) those born in north Italy but not in Verona, (iii) those born in the south of Italy.
A comparison group of 107 subjects was recruited from persons reporting to District Healthcare Centres for the health certification required of all public authority employees. The comparison group was chosen on the basis of place of birth (all inside the province of Verona) and age (similar to DUs). All subjects gave their informed consent to participate in the study.
Blood samples were collected to test for anti-HAV antibodies (EIA, Roche Laboratories, Mannheim, Germany). A single laboratory performed all the tests, without knowing whether the sample was from a DU or a comparison subject.
Analysis of variance was used to study continuous variables. Bonferroni correction was applied where multiple comparisons were performed. Fisher exact or 
2 tests were used to compare categorical variables. Multiple logistic regression was used to assess the statistical independence of risk factor variables. SPSS release 10.0 (SPSS Inc., Chicago, IL) was used for statistical analyses.15
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Results |
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Of the 404 heroin users recruited for the study, 81% reporting injecting as their primary route of administration and 19% reporting sniffing. The majority were receiving either methadone or buprenorphine treatment.
Table 1 shows the demographic characteristics of the DU groups and the comparison group. Of the 404 DUs, 305 (75.4%), were born in the Verona province, 55 (13.6%) in other regions in northern Italy and 44 (10.9%) in southern Italy. Among the DUs as a whole, the prevalence of anti-HAV was 28.7%.
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The study of the association between HAV positivity and the variables analysed shows that for DUs: the prevalence in males is 30.6% compared to 19.7% for females (P = 0.042); the mean age of HAV-positive DUs is 36.9 years (S.D. 4.9) versus 31.0 for HAV-negative DUs (S.D. 5.4) (P < 0.001); the average period of drug use is higher in HAV positive than negative subjects (16.4 years, S.D. 6.1 versus 11.6, S.D. 6.2; P < 0.001). Analysis of the control group shows no significant difference in terms of HAV prevalence for gender (P = 0.36); HAV-positive subjects were older (34.9 years, S.D. 6.7 versus 28.6, S.D. 5.1; P < 0.001).
Table 2 shows the results of the multivariate analysis among the DUs. Only age and region of birth were statistically significant independent predictors of anti-HAV. In the multivariate analysis among the comparison group, only age was statistically significant.
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Discussion |
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DUs born in the province of Verona have a prevalence of anti-HAV similar to the general population, suggesting that their lifestyle does not involve a substantial additional risk of HAV as has been reported elsewhere.6–10 The explanation may include a low endemic level of HAV in the Veneto region, among the lowest in the world,11 and changes in the risk behaviour of DUs. In the 1980s, Italy had the highest rate of HIV among DUs in industrialized countries. This led to the implementation of multiple HIV-prevention strategies and was followed in the 1990s by a drastic reduction in new infections.16 There were substantial reductions in the sharing of needles17 among injecting DUs, which would have also reduced parenteral transmission of HAV. Since the viral phase of HAV is quite brief,6–10 only regular, not occasional, sharing of needles would lead to significant parenteral transmission of the virus. A much higher prevalence of HAV was found in DUs born in southern Italy. This is more likely to be related to infection during infancy,12,13 than to the risk behaviour through injection. Similar results were reported in a recent Italian study for sewage plant workers, where correlated factors for HAV prevalence were age and birth in southern Italy.18
A number of factors need to be taken into consideration in vaccination schedules, including the features of the vaccine, the epidemiology of the infection and the disease, the feasibility and likely effectiveness of the vaccination programme. The recommendation to vaccinate DUs against HAV is fairly widespread,1–3 even in situations with low endemic levels, due to the risk of outbreaks and possible infection of the general population.6–10 Some authors subordinate the start of a vaccination campaign among DUs to proven higher risk groups and cases of local infection.19 Even if this approach to vaccination is accepted, vaccination of anti-HCV positive DUs is recommended in order to prevent superinfection, which although unlikely is potentially lethal.2,3,20 A possible approach could be to use the combined anti-HAV/HBV vaccination in place of anti-HBV vaccination, which is currently recommended and offered to all Italian DUs, albeit without data on immunogenicity in DUs.21,22 On the other hand, obligatory HBV vaccination for newborns and adolescents (since 1991 in Italy) could soon make anti-HBV vaccination for DUs superfluous. Compliance with anti-HBV vaccination for DUs in the Veneto region is very high,22–23 but doubts have been raised about the effectiveness of the anti-HAV vaccine schedule generally used.24
Studies evaluating the prevalence of HAV in different risk groups, especially in countries with very different levels of endemia, should consider the place of birth in order to exclude early childhood infection. Such data should be helpful in planning vaccination campaigns, which can be difficult and expensive to administer.
Key points
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Acknowledgments |
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The authors wish to thank Dr S. Ciaffoni, Dr A. Fornasiero, Dr C. Ferronato, Dr E. Motta and Dr M. Residori for their co-operation.
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References |
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