Changes in the epidemiology of hepatitis B virus infection following the implementation of immunisation programmes in northeastern Greece

The objective of this study was to investigate changes in the epidemiology of hepatitis B virus infection in the general population and selected groups of immigrants in the region of northeastern Greece over the last decade in relation to the introduction of hepatitis B vaccination programmes. Two population-based seroprevalence surveys were carried out during the years 1992-1994 and 1998-2006. In total, 25,105 individuals were tested for the presence of hepatitis B virus markers: HBsAg, anti-HBs and anti-HBc. Childhood/adolescence immunisation programmes began early in 1994 in selected groups of immigrants and were complemented by the national vaccination programme in 1998. Between 1992-1994 and 1998-2006, the HBsAg carrier rate declined from 5.4% [95% CI: 4.5-5.9] in adults (20-60 years old) and 1.9% [95% CI: 1.6-2.4] in children/adolescents (5-19 years old) of indigenous residents to 3.4% [95% CI: 2.9-3.8] and 0.6% [95% CI: 0.2-1.4] respectively (p<0.05). In spite of a decrease compared with 1992-1994, the percentage of HBsAg carriers was still relatively high in 1998-2006 among the Muslim religious minority group (8.2% [95% CI: 8.0-8.7] in adults and 2% [95% CI: 1.7-2.4] in children/adolescents) and in immigrants from the former Soviet Union (4.3% [95% CI: 3.6-4.7] in adults and 1.1% [95% CI: 0.8-2.4] in children/adolescents) (p<0.05 for both selected groups versus general population). The decline of the prevalence of HBsAg in the general population and selected groups of immigrants in northeastern Greece over the last decade supports the effectiveness of the ongoing immunisation programme although the information on the actual number of cases of acute HBV infection is not available.