الفهرس 
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Abstract
Hepatitis B virus (HBV) infection is a worldwide health problem affecting about two billion people and resulting in more than 520,000 deaths each year. In 1985 the overall prevalence among blood donors in Egypt has been shown to be 10.1% which has been decreased to be 2.1% in 2002 due to introduction of the HBV vaccine. Healthcare workers (HCWs) are at a greater risk for hepatitis B virus infection; According to WHO 5.9% of HCWs are exposed each year to blood-borne HBV infections which is about 66,000 HBV infections among HCWs worldwide.
The main transmission routes for HBV include perinatal infections, sexual contacts, the skin and mucous membrane infections due to contaminated blood or body fluids like in blood transfusion, use of contaminated syringes, hemodialysis and invasive tests or surgery. Clinical features of HBV infection ranging from asymptomatic carriers which often progress to chronic hepatitis, cirrhosis, and hepatocellular carcinoma.
HBV vaccination is an important strategy in prevention of HBV primary infection to decrease the risk of chronic HBV infection and its subsequent complications. HBVvaccines simulate an immune reaction by introducing the HBsAg in the body thus stimulating the innate and the adaptive immune system to develop anti-HBs antibodies. Seroprotection against HBV is defined as having an anti-HBs level above 10 IU/L one to three months after immunization; 90% or more of healthy adults demonstrating anti-HBs seroconversion after a vaccination series.
Anti-HBs levels after vaccination decrease over time. Serologic testing for anti-HBs is recommended for HCWs 1–2 months after the last dose of the vaccine. Many factors may be involved in the immune response to the vaccine and decreased vaccine immunogenicity include age (≥ 40 years), obesity, smoking, male gender, immune deficiency for any reason.
This cross sectional study was carried out to evaluate anti-HBs level among the vaccinated health care workers and to study risk factors for non-responders. Quantitative Enzyme Linked Immunosorbent Assay (ELISA) was used on blood samples collected from health care workers who were HBV vaccine compliant from different hospitals in Alexandria. Our study results showed a lower HBsAb titer in males rather than females, smokers, candidates with BMI ≥25, individuals vaccinated at old age (especially age ≥40) and in those who were vaccinated since more than 10 years.
Conclusion
- Our work shows that Enzyme Immuno Assay (ELISA) for determination of anti-HBs in human plasma and sera is important to evaluate antibody level especially in those at risk for occupational exposure.
- Anti HBs titer decreased over time.
- Male gender was associated with lower anti-HBs level than female gender.
Summary, Conclusion & Recommendations
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- We conclude that there is a negative correlation between anti-HBs titer and age at the time of vaccination; those who were vaccinated after the age of forty shows lower anti-HBs titer than those who were vaccinated at younger age.
- In our study we conclude that smoking has a negative effect on anti-HBs titer as smoking can affect humoral immune response.
- Anti-HBs titer was inversely associated with body mass index.
Recommendation
- Based on our study results we recommend to do post vaccination serologic testing routinely for HCWs especially among those at risk for occupational exposure.
- This study provides a basis for future investigations to determine true non responders through administration of booster dose of HB vaccine to candidates with zero titer and evaluate antibody response after 1-2 months.
- Further investigations are recommended to evaluate the specific immune memory for HBsAg among those with zero titer to determine the persistence and duration of immune memory after vaccination