study of hepatitis B vaccine efficacy 10 years after compulsory vaccination in Egypt

This study aimed to determine the protective efficacy of hepatitis B vaccine against infection and chronic carriage in 720 children aged 10 years who were vaccinated in infancy. All children were tested for hepatitis B serologic markers including hepatitis B surface antigen [HBsAg], antibody to hepatitis B surface antigen [anti-HBs], and antibody to hepatitis B core antigen [anti-HBc] using 3rd generation ELISA technique. Only 37.9% of vaccinated children had protective anti-HBs indicating its decay with time. Hepatitis B infection occurred in 6.8% of the vaccinated children and it induced a boosting effect on anti-HBs level. HBsAg was detected in 0.6% only of the vaqinated children. Thus we could conclude that up to 10 years, booster doses are unnecessary possibly due to protective anamnestic response to antigenic challenge. Further follow-up studies for longer duration than 10 years are needed especially during adolescence with the onset of sexual activity to monitor the vaccine efficacy in preventing chronic carriage and the possible necessity for booster doses.

Chronic hepatitis B antigenameia in bilharzial patients treated with praziquantel

One hundred and fifty two bilharzial patients together with one hundred and eighty four individuals as free controls were tested for HBsAg using ELISA technique. 6.6% of the former were carriers compared to only 2.2% in the later. It was found that past history of antibilharzial therapy, jaundice and presence of hepatosplenomegaly increased the risk of contracting HB virus infection. Praziquantel therapy showed 60% parasitological cure rate and 90% reduction in the mean egg count of bilharzial carriers of HBV infection. It improved both simple and early hepato-intestinal schistosomiasis as 5 out of 10 HBV carriers became free either from schistosoma ova or HBsAg after 6 months of treatment. In this work all chronic bilharzial carriers [5] had hepatosplenomegaly, 1 patient showed parasitological cure after treatment and the other four patients had a reduction in the mean egg count denoting the failure of praziquantel in improving their immunologic status and thus still HBsAg carriers