A viral disease against which vaccine is not available

Options

A. Measles
B. mumps
C. poliomyelitis
D. chicken pox

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a viral disease that does not have an available vaccine. This requires us to analyze the options given.

2. **Analyzing the Options**:
- **Option A: MERS (Middle East Respiratory Syndrome)**: MERS is caused by a coronavirus, and currently, there is no specific vaccine available for it.
- **Option B: Mumps**: Mumps is a viral disease for which a vaccine (MMR - Measles, Mumps, Rubella) is available.
- **Option C: Poliomyelitis**: Poliomyelitis, commonly known as polio, has a well-established vaccine.
- **Option D: Chickenpox**: Chickenpox is caused by the varicella-zoster virus, and there is a vaccine available for it (varicella vaccine).

3. **Identifying the Correct Answer**:
- From the analysis, we see that MERS is the only disease listed that does not have an available vaccine. Chickenpox does have a vaccine, while mumps and poliomyelitis also have vaccines.

4. **Conclusion**: The viral disease against which a vaccine is not available is **MERS**.

**Final Answer**: MERS (Option A).

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