Which medication prevents viral infections by priming the immune system against a specific virus?

• A. Immunosuppressant
• B. Antiviral drug
• C. Antibiotic
• D. Vaccine

Answer: (D)

Verified step by step guidance

1. Understand the role of each option: Immunosuppressants reduce the activity of the immune system, antiviral drugs inhibit the replication of viruses, and antibiotics target bacterial infections, not viruses.
2. Recognize that preventing viral infections by preparing the immune system to recognize and fight a specific virus involves stimulating an immune response before exposure to the virus.
3. Recall that vaccines work by introducing a harmless form or component of a virus to the body, which 'primes' the immune system to recognize and respond quickly to future infections by that virus.
4. Conclude that among the options, the medication that prevents viral infections by priming the immune system against a specific virus is a vaccine.
5. Note that vaccines are a preventive measure, unlike antiviral drugs which are used to treat infections after they occur.