Parliament passed the Infants Amendment Bill 2019 on Wednesday.
Dubbed by prime minister as the 'Law of Compassion', it was rushed through Parliament under urgency.
It comes as the death toll reached 76, most of whom are young children.
Prime Minister Tuilaepa Sailele Malielegaoi said the law would allow for stiff penalties for those who did not adhere to the compulsory vaccination law.
School principals stand to be fined up to $US3700 if they allow a child to be registered in school who has not been immunised.