Final answer:
Vaccines are harmless derivatives of viruses that stimulate the immune system to prevent infections by preparing it for future encounters with the pathogen, whereas antiviral drugs target viral replication during active infections.
Step-by-step explanation:
Vaccines for viral diseases are harmless derivatives of pathogenic viruses and help prevent infection by stimulating the immune system to mount a defense against the actual pathogen. Vaccines work by eliciting a protective immune response without causing the disease itself. They may include live attenuated viruses, inactivated viruses, or molecular subunits of the virus that trigger immunity. This immunity prepares the body to fight off future infections from the virus more effectively.
Antiviral drugs, on the other hand, include antiviral drugs like nucleoside inhibitors, protease inhibitors, and others that can target viral replication or other essential viral proteins. These are especially important in the treatment of active infections, as they help to control viral propagation and alleviate symptoms. However, when it comes to preventing viral diseases, vaccination is the primary and most effective strategy.