How effective is the 1st dose of the hepatitis b vaccine? can newborns catch hep b from close family after given the 1st dose?

It is effective - but the other doses has to be given too. There is also a vaccine to protect new-borns.

Newborns are often given their 1st HepB vaccine with booters given with other childhood vaccines. The boosters are necessary to maintain protection in the long term (years). The newborn use was started after they realized it could prevent infected mothers from passing it to their infants. Close family gatherings have little to no risk. It is a bloodborne disease. (and a bad one) not like staph