Therapy: Both case and control groups will receive a 3 year or longer entecavir or tenofovir therapy. Patients will be screen at 24-30 months and enrolled at 30 months after entecavir or tenofovir therapy. They will receive 5 Engerix-B injections at 0,1st ,2nd,3rd and 6th month [30-36 +/-1 month post nucleos(t)ide therapy] post enrollment. Both drugs will be discontinued after completed therapy.