1. General Features

In contrast to chemical medicines, vaccines usually exert their effects at or near the site of their introduction into the body. They do not need to be distributed through the bloodstream. Individuals often experience redness , tenderness or swelling at the site of the injection, and it is also common to have a slightly raised temperature following vaccination . Serious side effects are very rare. The risks associated with contracting the disease the vaccine prevents are considered to be greater than the risks associated with giving the vaccine. The same dose often works for most people, whatever their age, because of the way vaccines work.