A virus is a very small microorganism and it is different to other microorganisms as they are not classified as living things because viruses are not living cells. Viruses are much smaller than bacteria and living cells, therefore they are able to enter cells and reproduce quickly using the host cell’s mechanisms to survive and reproduce.
A cell will eventually burst after numerous viruses are produced and the viruses that are released will infect other cells. The symptoms of illness are caused by the bursting of cells. Aches, pain and high fever, as the body’s immune system fights the infection, are common symptoms of viral infections.
Vaccinating against viruses can prevent the body from developing the infectious viral diseases as the body’s immune system is prepared to destroy the virus.