In conclusion, the use of IFN as an immune adjuvant to HBV vaccine is safe and achieves an earlier and higher seroprotection rate improving Th1-dependent immune response in HD patients, suggesting that a similar strategy of IFN-adjuvanted HBV vaccination could be useful in other populations of HBV vaccine hyporesponders, such as cirrhotics and liver transplant recipients, who are at high risk of acquiring HBV infection [68]. This evidence concerns the gene IFNA1 and Huntington disease.