Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Med Princ Pract 2007;16:306–309 DOI: 10.1159/000102154 Assessment of Anti-HBs Antigen in 6- to 9-Year-Old Children Routinely Vaccinated via Vaccination Program in Iran Nahal Hadi a Negin Hadi b a Department of Bacteriology and Virology, and b Department of Community Medicine, Medical School, Shiraz University of Medical Science, Shiraz, Iran Introduction More than 300 million people worldwide are persis- tently infected with hepatitis B virus (HBV) and a sig- nificant proportion of these people develop severe patho- logic consequences such as chronic hepatitis, cirrhosis and hepatocellular carcinoma [1]. In Iran, hepatitis B car- rier rate was reported to be 1.7% in 1996 [2]. Among Ira- nian patients with cirrhosis, 70–84% had evidence of ex- posure to HBV and 51–56% are carriers. Patients with hepatocellular carcinoma show a 72% rate of exposure [3]. Immunization with hepatitis B vaccine is considered an effective means of prevention of infection with HBV and reducing occurrence of chronic sequelae related to the illness [4]. However, the disease still remains a global problem. Many factors contribute to the failure to control hepatitis B infection and morbidity, including the limit- ing nature of vaccination programs implemented initial- ly. Universal childhood HBV immunization may have a significant impact in decreasing the number of people with chronic HBV infection and this may limit its spread. The most common method employed for the prevention of HBV infection in the Middle East is by active immu- nization [5]. In Iran, since 1984 HBV vaccination of chil- dren at birth and high-risk groups was implemented by the Expanded Program of Immunization (EPI) [6] . Key Words Hepatitis  Vaccination  Anti-HBV antigen  Children  Iran Abstract Objective: To determine persisting antibody levels to hepa- titis B virus (HBV) antigen in healthy children, aged 6–9 years, vaccinated at birth. Methods: Blood samples were collected from 374 vaccinated children (178 girls and 196 boys) and 57 unvaccinated children, attending Shiraz Primary School, Shi- raz, Iran from September 2002 to April 2003. An HBV surface antibody (anti-HBs) was determined using enzyme-linked immunosorbent assay. Results: The anti-HBs titer was de- tected in 17% of the 8-year-old children, 7.7% of the 7-year- old children and 46.6% of the 6-year-old children. The de- crease was greatest in the 9-year-old children; more than half (54.3%) had a titer of less than 10 IU/ml, indicating a de- crease in antibody levels with increasing age/time. Con- versely, more than 35% of the 6-year-old children had a titer greater than 150 IU/ml compared with 24, 12 and 7% of chil- dren at the age of 7, 8 and 9, respectively, whose antibody titer was less than 150 IU/ml. Conclusion: Antibody titer de- clined with time. In comparison with other countries, the an- tibody titer in Iranian children was much lower. Copyright © 2007 S. Karger AG, Basel Received: January 29, 2006 Revised: June 18, 2006 Nahal Hadi Department of Bacteriology and Virology College of Medicine, Shiraz University of Medical Science Zand Street 71345, Shiraz (Iran) Tel. +98 7112 307 927 567, Fax +98 7112 304 356, E-Mail hadina@sums.ac.ir © 2007 S. Karger AG, Basel 1011–7571/07/0164–0306$23.50/0 Accessible online at: www.karger.com/mpp