## **Core Concept**
The concept of measles eradication revolves around achieving a high enough vaccination coverage to prevent sustained transmission of the measles virus. This requires understanding the basic reproduction number (R0) of measles, which is one of the highest among infectious diseases. The R0 for measles is estimated to be around 12-18, meaning one infected person can spread the disease to 12-18 others if the population is completely susceptible.

## **Why the Correct Answer is Right**
The correct answer, , is based on the principle that to achieve herd immunity and prevent outbreaks, the vaccination coverage must exceed the threshold required to keep the effective reproduction number (Re) below 1. For measles, with its high R0, this threshold is estimated to be around 93-95% of the population immune, either through vaccination or previous infection. This high threshold is necessary because measles is highly contagious and can spread quickly in a susceptible population.

## **Why Each Wrong Option is Incorrect**
- **Option A:** is too low because it does not account for the high contagiousness of measles and the need for a high level of herd immunity to prevent outbreaks.
- **Option B:** is still below the estimated threshold needed for measles eradication and does not ensure that the effective reproduction number (Re) will be below 1.
- **Option D:** exceeds the minimum required threshold but is not necessary for measles eradication; aiming for is sufficient and practically achievable.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that achieving and maintaining high vaccination coverage is critical for measles eradication. This requires not only initial high coverage but also ongoing efforts to vaccinate new birth cohorts and address any gaps in immunity. Measles elimination has been achieved in some regions, demonstrating that with sustained effort, it is possible.

## **Correct Answer:** .