@ 42--56 days old. Here in washington state we have just had a pertussis epidemic so early pertussis vaccine in a newborn is important. 42 days is the earliest day to vaccinate but it may be better to wait until 8 weeks old in case the vaccine causes a fever.
Depends. The hepatitis B vaccine was originally tested in infants of Hep B positive mothers, giving it shortly after birth. It was not only effective in reducing Hep B in the states population but within years reduced the frequency of liver failure & need for transplants. It can be given within hours of birth. Others are done around 6- 8 wks because this is when they have shown the ability to be effective.