Vaccines and herd immunity. Which statement is true?

• A. Vaccines protect only those who are vaccinated
• B. Vaccines have no effect on community
• C. Vaccines help create herd immunity that protects the community, including those who cannot be vaccinated
• D. Herd immunity can be achieved without vaccines

Answer: (D)

Herd immunity happens when enough people are immune to a disease that transmission drops, protecting those who aren’t immune. Vaccines contribute to this by giving individuals immunity without getting sick, which reduces spread in the whole population. That indirect protection reaches people who can’t be vaccinated or don’t respond well to vaccines. While herd immunity could theoretically occur if many people gain immunity through infection, relying on natural illness would cause avoidable sickness and death. Vaccines provide a safer, practical path to achieve herd immunity.