For the prevention of yellow fever, a single vaccination with 17-D nonpathogenic strain of virus gives full protection to the individual for at least
**Core Concept**
The underlying principle being tested is the duration of immunity provided by the 17-D vaccine, a live, attenuated vaccine used for the prevention of **yellow fever**, an acute viral hemorrhagic disease transmitted by infected **Aedes** mosquitoes.
**Why the Correct Answer is Right**
The 17-D vaccine stimulates a strong immune response, inducing both humoral and cellular immunity, which provides long-term protection against **yellow fever virus**. This vaccine has been shown to offer **lifelong immunity** in most cases, with a single dose being sufficient for full protection.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it underestimates the duration of immunity provided by the vaccine.
**Option B:** Similarly, this option is incorrect as it does not reflect the long-term protection offered by the 17-D vaccine.
**Option C:** This option is also incorrect as the duration of immunity exceeds this timeframe.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the 17-D vaccine is highly effective and offers **lifelong immunity** against yellow fever, making it a crucial tool in preventing outbreaks of this disease, particularly in endemic areas.
**Correct Answer:** D. 10 years, but essentially provides lifelong immunity, however the correct answer choice is not fully provided in the question.