Evaluation of the Effectiveness of Hepatitis B Vaccine among Vaccinated Adults in Misurata, Libya

Hepatitis B virus (HBV) is a blood-borne and sexually transmitted virus. Rates of new infection and acute disease are highest among adults, especially medical staff. Hepatitis B vaccination is the most effective measure to prevent HBV infection and its consequences particularly unvaccinated adults at increased risk for infection. This study was planned to evaluate the effectiveness of HBV vaccine among adults in Misurata city, Libya and to identify personal factors associated with serologic evidence of the immune response. This field trial study was conducted on 143 randomly selected adults attending Shohada Almakasba and Central Public Dental Clinic hospitals at Misurata city during the period from March 2013 to February 2014. They were classified into 3 catigories; 56 non health care worker adults (30 males and 26 females), 67 medical staff member (34 males and 33 females), in addition to twenty controls (10 males and 10 females) who did not receive any dose of hepatitis B vaccine). The hepatitis vaccine (Engerix ™ -B) used in Libyan vaccination centers, were chosen to vaccinate the participants. Serum samples for each participant were tested for the quantitative determination of anti-HBs antibody using Enzyme Linked Fluorescent Assay (Biomeureux). In our study, after vaccinating the studied group by three doses of HB vaccine, majority of them achieved a protective level of anti-HBs (84% and 86.3% for males and females respectively). While, only 16% of vaccinated males and 13.7% of vaccinated females showed immunoprophylaxis failure. The percentage of negative response to the first and second dose of hepatitis-B vaccine was 41% and 27% in males and 59.3% and 47.5% in females respectively. There is a statistical significant difference in the Mean (SD) of the expression of Hepatitis Bs antibodies titer after 1st , 2nd and 3rd doses of vaccination from that of control group. There is a strong negative correlation between Hepatitis Bs antibodies titre after vaccination (1st dose, 2nd dose, 3rd dose) and age. Also there is no statistical significant difference between health care workers and non health care groups as regard response to vaccination after1st, 2nd or 3rd dose of vaccination. Finally, univariate analysis illustrated that there is a high statistical significant association between age and expression of Hepatitis Bs antibodies titre. While, other factors (gender, co-morbidity, parent vaccination, smoking habit); showed no significant association. These results suggested that Hepatitis B vaccination is the veryeffective measure to prevent HBV infection especially when given at younger age. All adults should be vaccinated by Hepatitis B vaccine with focusing on high risk groups.