Which statement best describes the role of herd immunity in school vaccination policies?

• A. Herd immunity means everyone must be vaccinated to avoid disease.
• B. Herd immunity is only relevant for adults.
• C. Herd immunity is achieved without high vaccination coverage.
• D. Herd immunity reduces disease spread and protects those who are not vaccinated.

Answer: (D)

Herd immunity occurs when a large portion of a population is immune, typically through vaccination, which interrupts disease transmission. In school vaccination policies, this creates a protective shield that lowers the chance of spreading the disease to others and helps safeguard students who cannot be vaccinated. Therefore, the statement that herd immunity reduces disease spread and protects those who are not vaccinated best captures its role in school policy. It does not require that every individual be vaccinated, it applies to all ages, and it relies on maintaining high vaccination coverage to be effective.