The vaccinations are given by GPs and nurses, usually in doctors' surgeries. It tends to start suddenly with symptoms such as fever, chills, headache, aching muscles and feeling generally unwell, together with a cough or sore throat. It is usually much more than a simple head cold, although people sometimes call a heavy cold 'flu'. Colds are more likely to start gradually with a sore throat and stuffy or runny nose and to be less severe. Flu is spread by coughs and sneezes from people who are already infected with the virus and it can spread very rapidly.
Influenza is around every winter.
Most of it occurs within a few weeks, so that a lot of people are ill at the same time. The viruses are always changing, so this winter's flu will be slightly different from last winter's. If it is a very bad year, this may amount to what is called an epidemic. How much flu there will be each year is difficult to predict. For most people, flu is a nasty experience.