Most people when they complain of flu are only experiencing a bad cold whether it be a head, throat or chest cold or all three.
If someone has "real" flu then they will be so ill they cannot get out of bed.
With real flu people have fever, sore muscles and often a nasty chest infection.
It would be interesting to find out how the government etc do their surveys and if it's the case of a large number of people self
reporting then this surely must be suspect?