Hi @DBuddha,
Just moving this to the appropriate thread. As mentioned above, HDV infection (which is caused by a completely separate virus) is only possible if you are also infected with HBV.
If you are protected against HBV via vaccination, you are also protected against HDV.
Interferon can be used to treat HDV, but it has poor efficacy in most cases. It can also be treated with bulvertide, which is not widely available or accessible in much of the world.
Hope this helps,
Thomas