Why is herd immunity beneficial?

• A. It makes it less likely for infectious diseases to spread through the population.
• B. It vaccinates every individual automatically.
• C. It increases the mutation rate of pathogens.
• D. It guarantees everyone will never get sick.

Answer: (A)

Herd immunity reduces spread by lowering the number of susceptible people in a community. When many individuals are immune, there are fewer opportunities for the pathogen to move from person to person, which cuts the effective reproduction number and can cause transmission to die out. This also helps protect those who cannot be vaccinated or do not respond well to vaccines, because the overall level of transmission in the population is reduced. So the main benefit is making it less likely for infectious diseases to spread through the population. It doesn’t automatically vaccinate everyone, it doesn’t increase pathogen mutation rates, and it doesn’t guarantee that no one will ever get sick.