Journal of Medical Virology 9999:1–6 (2009) Seroepidemiology of Hepatitis A Among Greek Children Indicates That the Virus Is Still Prevalent: Implications for Universal Vaccination A. Kyrka, 1 A. Tragiannidis, 2 D. Cassimos, 3 K. Pantelaki, 4 M. Tzoufi, 5 M. Mavrokosta, 6 X. Pedeli, 7 F. Athanassiadou, 2 A. Hatzimichael, 3 A. Konstantopoulos, 1 D. Kafetzis, 1 and V. Papaevangelou 1 * 1 2nd Department of Pediatrics, University of Athens Medical School, ‘‘A. Kyriakou’’ Children’s Hospital, Goudi, Athens, Greece 2 2nd of Department of Pediatrics, Aristotle University of Thessaloniki Medical School, Thessaloniki, Greece 3 Department of Pediatrics, Democritus University of Thrace, Alexandroupoli, Greece 4 Blood Bank Laboratory, ‘‘A. Sophia’’ Children’s Hospital, Goudi, Athens, Greece 5 Department of Pediatrics, University of Ioannina Medical School, Ioannina, Greece 6 Pediatric Q2 Clinic, Venizelos General Hospital, Iraklion, Crete, Greece 7 Department of Hygiene and Epidemiology, University of Athens Medical School, Goudi, Athens, Greece A national cross-sectional seroprevalence survey was conducted in order to evaluate the current seroepidemiology of hepatitis A among 1,383 children, aged 0–14 years, residing in Greece. Stratification of the study population was con- ducted according to age and area of residence. Sera from study participants were tested for the presence of anti-HAV IgG antibodies. Immigrant children, as well as children residing in rural areas, had lower immunization rates. Among unvaccinated children, the seroprevalence rate of anti-HAV was 17.1%. Nationality was shown to have a marginally significant effect since non- immunized immigrant children had a higher seroprevalence rate (22.4% vs. 15.9%, OR ¼ 1.52, P ¼ 0.064). Significant differences between geo- graphic areas for both vaccination coverage and natural immunity were observed. The study findings indicate that hepatitis A is prevalent in Greece and therefore universal infant hepatitis A immunization should be implemented. J. Med. Virol. 00:1–6, 2009. ß 2009 Wiley-Liss, Inc. KEY WORDS: hepatitis A; vaccine; seroepi- demiology INTRODUCTION Hepatitis A is one of the most frequently reported vaccine-preventable diseases worldwide and remains endemic in many areas of the world [Gust, 1992]. In areas marked by an increased prevalence rate for hepatitis A, the infection is observed primarily among children and most frequently manifests itself as an asymptomatic self-limiting disease, contributing pro- tective immunity to the disease during consequent adulthood [Shapiro, 2003]. Conversely, in areas marked by an intermediate prevalence rate for hepatitis A, a limited proportion of the adult population is reported to be immune. As a result, community-wide epidemics, resulting from person-to-person transmission may occur [Shapiro, 2003]. Finally, in areas marked by a low prevalence rate for hepatitis A, residents may be at risk for infection by travel to areas where hepatitis A is endemic and ingestion of local contaminated foods [Shapiro, 2003]. Hepatitis A, although with a mild course during childhood, may cause significant morbidity and morta- lity among both adolescents and adults [Shapiro, 2003]. Fulminant hepatitis may also develop among individu- als with a predisposing underlying liver disease [Sha- piro, 2003]. Significant epidemiologic changes of this vaccine-preventable disease have been observed during the past few decades. In several developing countries, the decline observed in the seroprevalence rates of anti- HAV is attributed mainly to the improvement of socio- economic conditions and enhanced access to sanitary water sources [Innis et al., 1991; Bell and Feinstone, 2004; Jacobsen and Koopman, 2004; Srinivasa Rao et al., 2006]. However, secondary to increases both in immigration to developed regions and travel to devel- oping areas, population exchanges between developed and developing areas has been augmented during the JMV-08-0924.R2 Grant sponsor: ESPID Q3 (2006); Grant sponsor: GSK. *Correspondence to: V. Papaevangelou, MD, 2nd Department of Pediatrics, University of Athens, ‘‘P. & A. Kyriakou’’ Children’s Hospital, Thivon & Livadias str, Goudi, 11527 Athens, Greece. E-mail: vpapaev@med.uoa.gr Accepted XXXXXX Q1 DOI 10.1002/jmv.00000 Published online in Wiley InterScience (www.interscience.wiley.com) ß 2009 WILEY-LISS, INC.