What is the needed percentage of people that need to be vaccinated, for there to be herd immunity? And, what is the efficacy of the vaccine for Samoans? That

What is the needed percentage of people that need to be vaccinated, for there to be herd immunity? And, what is the efficacy of the vaccine for Samoans? That is if you need 80% immunized for herd immunity and 95% of the immunized group develop antibodies, then you need more than 80% to be immunized.