Response to Recombinant Hepatitis B vaccine (Engerix-B) and TWINRIX [Hepatitis A & Hepatitis B Vaccine] In Health care Workers at Prince Sattam Bin Abdul Aziz University Hospital, Al-Kharj Saudi Arabia

Background/Aims: Hepatitis B virus (HBV) infection is a major cause of liver-related morbidity and mortality. Infection with HBV can be prevented by vaccination with several forms of HB surface antigen (HBsAg) based vaccines. In the current study we assessed the efficacy and safety of both monovalent vaccine (Engerix) and HBV/HAV combination vaccine (Twinrix). Methodology: Health care workers from Prince Sattam Bin Abdul Aziz University Hospital, Al Kharj with undetectable antibody to HBsAg were given 3 doses of either Engerix-B, 20 µg (1 mL),or Twinrix (720 ELISA units of inactivated hepatitis A virus and 20 µg of recombinant HBsAg protein) at 0, 1, and 6 months The route of administration was intramuscular injection. The primary outcome was the difference in proportion of patients achieving an anti-HBs antibody titer >10 IU/mL at 7 months. Results: Out of 989 participants, 617 had HBsAb titers less than 10 IU/ml. Therefore, HCWs were randomly assigned to receive either Engerix B (n=309), or Twinrix (n=309). In Engerix recipients, 83.7% developed a protective antibody response after vaccination versus (94.7%) in participants who received Twinrix. With Engerix, the antibody titers ranged between 50 mIU/ml, and 683 mIU/ml versus 106 to 964 with Twinrix after the complete vaccination schedule. Antibody response was significantly higher among non-Saudis compared to Saudis. Conclusion: Both HBV monovaccine and combination vaccines are effective and safe. However, given the higher immunogenicity of HBV/HAV combination vaccine, it may be more suitable for adults in regions where HAV is not endemic.