In recent years, vaccines have come under scrutiny for possibly causing autism and other potentially serious side effects. Even though those concerns have been proven false, and the benefits of vaccines outweigh their risks, the rate of vaccines is declining, which is affecting herd immunity. Which of the following statements about herd immunity is correct

Herd immunity protects those individuals who are not immune to the disease because the number of susceptible individuals is reduced greatly.

Explanation:

The immunity provided by the major population which is immune to a particular contagious disease to some of the individuals of population which is not immune to the disease is called herd immunity.  

Herd immunity is achieved when a large percentage of the population is vaccinated for that infectious disease for example herd immunity for measles requires 92-95% of the population to be vaccinated.  

In this case, the disease is not able to cross the barrier of the immune population and so do not able to infect susceptible individuals.