Final answer:
Custom virus fighting molecules are known as antibodies, and they are specific to particular pathogens. Vaccines are designed to prevent viral infections by eliciting an immune response without causing the disease, and antiviral drugs work by inhibiting viral replication within host cells.
Step-by-step explanation:
Custom virus fighting molecules are called antibodies. These molecules are critical components of the immune system and are produced in response to antigens, which are proteins typically found on the surfaces of pathogens like viruses. Antibodies have the ability to attach to specific antigens, thereby neutralizing the pathogen, marking it for destruction, or inhibiting its activity. This interaction is highly specific; antibodies produced in response to one virus generally won't recognize or bind to another.
Vaccines are a primary method of preventing viral diseases, including those caused by influenza and coronaviruses like SARS-CoV-2. They work by stimulating an immune response in the body without causing the disease itself. Vaccines may be prepared using live but attenuated (weakened) viruses, killed viruses, or molecular subunits like viral proteins which cannot cause disease but still provoke an immune response.
Moreover, antiviral drugs, such as Tamiflu and Relenza for influenza, work by interfering with the virus's ability to replicate within host cells. Some antiviral drugs are designed to mimic DNA building blocks, thus stopping the viral replication process, leading to inactive viral DNA. Unfortunately, viruses can evolve and become resistant to these treatments, as seen with HIV that constantly changes the proteins on its surface to evade the immune system.