HBV is the most common chronic viral infection in the world and represents a major global healthcare challenge with significant morbidity and mortality. An estimated 887.000 people die annually from complications of persistent infection, liver cirrhosis and HCC.
In Egypt, despite shifting to low endemicity area of HBV with HBsAg prevalence (< 2%) with the rapid expansion of the coverage of hepB vaccinations following their addition to the national immunization program, HBV still represents disease burden in Egypt.
There are three major modes of HBV infection: perinatal, sexual transmission and unsafe injections. In addition to these modes of transmission, horizontal transmission through household/close contact which causes "intra-family clustering" also plays a crucial role in spreading HBV.
A series of three doses of HepB vaccination can induce long-term protection as it excites antibody response and anti-HBs level ≥10 IU/L are usually sero-protective. More than 90% of healthy individuals younger than 40 years of age drop to 60-70% in adults over age 60 y and more than 95% of healthy infants achieve protective immunity.
As some individuals do not develop sufficient levels of anti-HBs, testing for evidence of protective immunity to HBV vaccination is required.
Regarding the immunogenicity of hepB vaccine our study estimated 72.9% sero-positive results among vaccinated participants with significant reduction of the titer or being negative with increasing the age or the time since the last vaccination dose. Interfamilial spread was detected in (27.8%) of the families included (29/104).