People often ask me why we give hepatitis B shots so early, given that there is a relatively low risk of infection in the US.
Well... first off, the low risk of infection is because we have diagnosed and vaccinated and no longer take blood products from hepatitis B patients. The number has fallen dramatically in recent years. We also have an effective treatment that cures the disease. Mind you, the treatment does not reverse the damage caused by the virus, it just halts it when you receive it.
The problem is that early infections in childhood are usually not discovered for years and the chronic damage is significant in this population and life long. And hepatitis B is only found in humans, so vaccination would have wiped it out at some point, although it seems unlikely that we will have this opportunity now.
The hepatitis vaccine is also extremely safe with a very low risk of side effects.