Trill a bit of vacc history for you..
originally the hep b was only given to those babies whose parents lived "risky" lives(sex workers, aboriginals ) Then becasue australia become more accepting of others and there were more "mixed" (i dont like this terminology) Marriages and drug use was no longer just for those in lower socio econmical areas or sex workers it was decided it would be offered to everyone. That way those who lie about sexual encounters or drug use wouldnt miss out on thier children having the vax.

for the sceptics this information is from a women who has been working with women and babies for 40 years(and still is) and has seen these at birth vax come in and out over the years.