Compared to the flu, a cold is not a big deal. Some people think they have the flu when they have a cold. The following info may be helpful (for everyone):
"Influenza, commonly called the flu, can be a serious illness that is sometimes fatal. Infection with the influenza virus may lead to a stay in hospital for any age group but particularly if you are elderly or have an ongoing medical condition. Influenza can make an existing medical condition, such as asthma or diabetes, a lot worse.
Even if you do not end up in hospital, influenza can keep you in bed for a week or more, preventing you from doing work,sport or just about anything that requires leaving the house
Influenza is different from a cold. A cold virus only affects the nose, throat and the upper chest and lasts for a few days, whereas influenza can be a serious illness that affects the whole body and can last up to a week or more.
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Source:
http://www.fightflu.co.nz/faq "How can I tell the difference between a cold and influenza"