Persistence of antibody to hepatitis B surface antigen among vaccinated children in a low hepatitis B virus endemic area.

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.

Seroepidemiology of hepatitis A virus in children of different age groups in Tehran, Iran: implications for health policy.

BACKGROUND: Hepatitis A is one of the most frequently reported vaccine-preventable diseases throughout the world and remains endemic in many areas. Studies in various communities have shown that Hepatitis A virus (HAV) prevalence rises with age. The current data regarding hepatitis A epidemiology in Iran is limited. The aim of this study was to determine the seroepidemiology of hepatitis A in children of different age groups in Tehran, Iran. METHODS: Plasma samples of 1065 children between ages of 6 months and 20 years were tested for the presence of total anti-HAV. The study population was stratified according to age. RESULTS: The prevalence of total anti-HAV was 61.6%. HAV prevalence rates according to age groups were as follows: 61.5% between 6 months and 1.9 years, 51.7% between 2 and 5.9 years, 52.9% between 6 and 10.9 years, 65.2% between 11 and 15.9 years, 85% between 16 and 20 years. Total anti-HAV seroprevalence was significantly different between age groups. CONCLUSION: The study findings indicate that hepatitis A is prevalent in children in Tehran, Iran and HAV infection is an important public health problem in this region.

Lack of occult hepatitis B virus infection among blood donors with isolated hepatitis B core antibody living in an HBV low prevalence region of Iran.

BACKGROUND: Occult hepatitis B virus (HBV) infection in blood donors is considered a potential threat for the safety of the blood supply, however conclusive studies on this issue are lacking. The aim of this study was to assess the occult HBV infection in blood donors with isolated hepatitis B core antibody (anti-HBc) living in the city of Arak, in the Central Province of Iran, as a low prevalence region for HBV. METHODS: A total of 531 voluntary blood donors in Arak, Iran were included in this study. Hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), anti-HBc, and hepatitis C antibody (anti-HCV) were tested in all subjects. The presence of HBV-DNA was determined quantitatively in plasma samples of cases with isolated anti-HBc (HBsAg-negative, anti-HBs-negative, and anti-HBc-positive) by real-time PCR using the artus HBV RG PCR kit on the Rotor-Gene 3000 real-time thermal cycler. RESULTS: Of 531 subjects enrolled in this study, 11 (2.1%, 95% confidence interval 0.8-3.2%) had isolated anti-HBc. HBV-DNA was not detected in any of the cases with isolated anti-HBc. CONCLUSIONS: Our study showed that all the blood donors with isolated anti-HBc were negative for HBV-DNA, and occult HBV infection did not occur in the blood donors of this low prevalence region for HBV infection.