I'd like to know if a carrier of hepatitis b can cause symptoms to others by infection even if the carrier themselves aren't affected due to having antibodies. also, how long after getting antibodies due to infection will the immunity expire?

Some people with hepatitis B virus (HBV) without symptoms ("carriers") are more able to transmit infection than others. Additional blood tests can help identify those who are most infectious, but every HBV infected person must take steps to prevent transmission. Once antibodies are present -- from past infection or vaccination -- immunity to new infection usually is life long.