How early can orphan pups be innoculated safely please

From what I understand, because Orphans have very little, if any Maternal Antibody protection it can be done much earlier than normal. Be guided by your vet, but I would think 5 or 6 weeks, though they may want to do 3 Jabs instead of two, an early one and then at the normal times, which varies with th4e diferent makes of vaccine!