herd immunity
(… ih-MYOO-nih-tee)
Protection
from an infectious disease as a result of living in a
community where a large number of people are vaccinated
against that disease. When enough people are vaccinated
against a disease, it is harder for the disease to spread.
Herd immunity helps protect those
who have not been vaccinated, including newborns, pregnant
women, and people with certain illnesses who cannot receive
vaccines. Also called community immunity.