Influenza vaccines prevent or mitigate infections. They are designed to induce a protective immune response in the body against the viruses represented in the vaccine. When vaccinated, the immune system of the body produces a specific response, consisting of specific T cells and specific antibodies that fight off the infection when exposure to the virus occurs at a later stage. More importantly, vaccination also leads to the induction of a specific immunological memory against the viruses represented in the vaccine. Upon contact with the virus at a later stage, the immune system is able to mount a specific response much more rapidly than the non-primed immune system.
Antivirals are drugs that can treat people who have already been infected by a virus. They also can be used to prevent or limit infection when given before or shortly after exposure, before illness occurs. A key difference is that the antiviral drug is effective only when administered within a certain time frame before or after exposure and is effective during the time that the drug is being administered.
Antibiotics are medicines that interfere with the reproduction of bacteria and are, therefore, only useful for treating bacterial infections. Viral diseases, like influenza, can therefore not be treated with antibiotics. What is worse, inappropriate use of antibiotics contributes to the development of antibiotic resistance, a growing health concern. Secondary bacterial infections that may occur in tissues that have been damaged by influenza virus infection may well be treated with antibiotics.