Author Affiliations: Clinical Research Dept., Pasteur Institute of Iran, Tehran, Iran (Aghakhani A, Khadem-Sadegh A, Eslamifar A, Ramezani A); Iranian Society for Support of Patients with Infectious Diseases, Tehran, Iran (Banifazl M); Iranian Blood Transfusion Organization Research Center, Iran (Izadi N); University of California, San Francisco, USA (McFarland W); Arak University of Medical Sciences, Arak, Iran (Sofian M); Pediatric Dept., Shahid Beheshti University of Medical Sciences, Tehran, Iran (Pournasiri Z); Iranian Research Center for HIV/AIDS, Tehran, Iran (Foroughi M)

Corresponding Author: A Ramezani, Clinical Research Dept., Pasteur Institute of Iran No 69, Pasteur Ave., Tehran, 13164, Iran (Tel: +98 21 66968852; Fax: +98 21 66465147; Email: amitisramezani@hotmail.com; iiccom@iiccom.org)

doi: 10.1007/s12519-011-0286-4

Background: A potential problem of hepatitis B immunization is that vaccine-induced antibody to hepatitis B surface antigen (anti-HBs) declines to low levels with age. This study investigated the persistence of anti-HBs in vaccinated children in a low hepatitis B virus (HBV) endemic area.

Methods: Plasma samples of 938 children between ages of 8 months and 15 years were tested for the presence of anti-HBs.

Results: The seroprotection rate was 60%. Protective antibody level was detected in 65% of children one year after vaccination, and in 30%, 29% and 24% 5, 10 and 15 years after vaccination, respectively. The mean anti-HBs titer declined with post-vaccination time (to 66 mIU/mL in 1 year, 60 mIU/mL in 5 years, 40 mIU/mL in 10 years to 37 mIU/mL in 15 years after vaccination).

Conclusions: Children vaccinated against HBV during infancy may show low levels of antibody during adolescence. Our data suggest that a booster dose of vaccine may be required in low HBV endemic areas.

Key words: children; hepatitis B surface antibody; hepatitis B virus; Iran

World J Pediatr 2011;7(4):358-360