How does Herd/Community Immunity work?

• Herd/Community immunity works by breaking the chain of infection. If 90% of people are immune to an infection, it is hard for the organism to find a person to infect and thus the spread of infection is broken. n• Many vaccine preventable diseases are highly contagious – for example Measles is so contagious that 90% of people susceptible to the infection who come into contact with someone who has the disease will be infected.