Flu, Influenza and flu vaccination
Flu, or Influenza as it is officially called, is not the same as a common cold. Whilst both are viruses, the Influenza virus is usually more serious and can often be prevented by having an annual vaccination. These are usually available in March, some years (eg 2015) the manufacture of the vaccine is delayed due to a late change in the virus strain. Most years the virus tries to outwit its host by underging a slight change or mutation. By doing this it can circumvent our natural immunity from last years flu infection. Recent evidence suggests protection against influenza may start to decrease from 3 to 4 months following vaccination and early vaccination needs to be balanced with this.