Abstract

Background and Aims: Hepatitis B infection is a serious public health problem worldwide. It has been shown that the levels of antibody to hepatitis B surface antigen (anti-HBs) decrease after vaccination. The main objective of this study was to assess the level of anti-HBs among children after primary vaccination against hepatitis B virus (HBV) in Tehran, Iran. Methods: The study was conducted in four selected healthcare centers in Tehran during a 6-month period from September 2005 to March 2006 in Tehran. Blood samples collected from 165 healthy, 1- to 5-year-old children who had been vaccinated against HBV were tested for anti-HBs using enzyme-linked immunosorbent assay (ELISA). Results: Approximately 47.9 of the cases were male. Among the cases, the minimum and maximum titers of hepatitis B surface antibodies (HBsAb) were zero and 1000 m IU, respectively. The mean level of HBsAb titer in this study was 232.64 m IU, with a standard deviation of 278.711 m IU. Conclusions: The results showed that HBsAb titer may decrease over time after vaccination. Finally, along with prevention and control strategies, ongoing investigation and monitoring of antibody levels against HBV in children and other age ranges is recommended.