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42Natalia Kruszewska, Jan Styczynskiachieved when vaccination took place before cancerdiagnosis [5].Another important issue is the decreased rate ofHCV-infected patients. The use of serological methodsfor the diagnosis of HCV infection is not optimal,because of a risk of delayed seroconversion due toimmunosuppression. However, the same method wasused in both analyzed groups. Despite the lack of specificHCV prophylaxis, it was significantly reduced,comparably to the rate of HBV infections. This observationhighlights the importance of non-specific methodsin preventing HCV transmission. The non-specificprophylaxis can play an important role in reducingfrequency of HBV infections, in addition to vaccinations.In previous decade, HBV and HCV infectionsamong children with malignancy in Poland were consideredto occur mainly during or following the treatmentof neoplastic disease [6]. Contrary to this observation,all HBV infections in the last analyzed periodwere present at the beginning of treatment among theexamined patients. No new HBV infections have beennoted during therapy over the last 4 years.World Health Organization (WHO) recommendsroutine vaccination of all infants against HBV infectionas an integral part of national immunization schedulesworldwide [7]. The main purpose of this strategy is toprotect the population from chronic HBV infections,which might be followed by liver cirrhosis and hepatocellularcancer. At the same time the mandatory vaccinationshelp to prevent hepatitis B in high risk groups,such as children with malignancy.CONCLUSIONS1. Introduction of routine vaccination against HBVhelped to control HBV infections among childrenwith malignancy.2. Coinciding reduction of HCV infections shows theimportance of non-specific prophylaxis.3. Currently, the risk of HBV and HCV infectionsduring anticancer treatment in children does not exceedgeneral population risk.REFERENCES1. Styczyński J., Wysocki M., Kołtan S. et al.: Epidemiologicaspects and preventive strategy of hepatitis B andC viral infections in children with cancer. Pediatr. Infect.Dis. J. 2001, 20, 1042-1049.2. Gorczyńska E., Bogusławska-Jaworska J.: Efficacy ofspecific passive immunization in limiting endemic wardhepatits B virus (HBV) infections. Post. Med. Klin.Dośw. 1992, 1, supl., 17-24.3. Madaliński K., Gregorek H., Zembrzuska-Sadkowska E.et al.: Immunogenicity of Engerix B vaccine in 786 childrenwith risk of hepatitis B infections. Hepatol. Pol.1998, 5, supl.1, 93-98.4. Woźniakowska-Gęsicka T.: Przewlekle WZW – aspektyepidemiologiczne i kliniczne. Fam. Med. Prim. Care Rev.2007, 4, 1021-1025.5. Baytan B., Gunes A.M., Gunay U.: Efficacy of primaryhepatitis B immunization in children with acute lymphoblasticleukemia. Ind. Pediatr. 2008, 45, 265-270.6. Januszkiewicz D., Wysocki J., Nowak J.: Hepatitis B andC virus infections in Polish children with malignancies.Eur. J. Pediatr. 1997, 156, 454-456.7. WHO: Weekly epidemiological record. 2004, 79, 253-264.Address for correspondence:Jan Styczyński, MD, PhD,Chair and Clinic of Pediatric Hematologyand OncologyNicolaus Copernicus UniversityCollegium Medicum in Bydgoszczul. Curie-Sklodowskiej 985-094 BydgoszczPolande-mail: jstyczynski@cm.umk.pltel: +48 52 585 4860fax: +48 52 585 4867Received: 9.10.2008Accepted for publication: 20.12.2008