Final answer:
Prophylactic agents are drugs used to prevent or lessen the severity of diseases, one class of which is antiviral drugs that treat viral infections by inhibiting the development of the virus.
Step-by-step explanation:
Certain drugs that are used to ward off or lessen the severity of a disease are called prophylactic agents. These agents include a variety of medications such as antiviral drugs and vaccines, used to prevent viral infections or reduce their severity. Antiviral drugs, like Tamiflu and Relenza, are specifically designed to treat viral infections by inhibiting the virus's development rather than destroying the virus outright. It's essential to understand that while antibiotics are intended to kill or inhibit the growth of bacteria, antiviral drugs are used against viruses and do not affect bacteria. Some antiviral medications are developed to be virus-specific, whereas others, known as broad-spectrum antivirals, are effective against a wider range of viruses.