The flu – or influenza – is a respiratory infection, caused by viruses that are circulating all over the world.
There are actually four different types: A, B, C, and D, but the D viruses mostly just affect cattle, and the C virus is not very common.
The B and A viruses on the other hand, typically cause seasonal epidemics, most of which occur during the winter months.1
Who can catch flu?
The flu spreads quite easily, with crowded spaces such as schools and nursing homes seeing more rapid transmission.
Anyone can get the flu, but some people are more susceptible to getting it or to developing complications.
These people include babies and toddlers, pregnant people, the elderly, and people with specific medical conditions.
Health care workers are also at a high risk of acquiring the influenza virus.2
Cold and flu symptoms – what are the differences?
The most typical symptoms of seasonal influenza are a sudden onset of fever, a usually dry cough, headache, muscle and joint pain, a runny nose, sore throat, and a general feeling of being unwell.3
You may also feel tired or exhausted, have difficulty sleeping, a loss of appetite, diarrhoea, or stomach pain.4
A cold, on the other hand, appears quite gradually and mainly affects your nose.
You can usually carry on as normal with a cold, whereas the flu may make you feel too exhausted to work or carry out your tasks.5
High risk demographics – particularly people over the age of 65—may be susceptible to a more severe version of the flu, or even death.
People in poorer countries make up the vast majority of deaths, likely due to lack of access to care.6
If you get more severe symptoms, such as chest pain, shortness of breath, difficulty breathing, or you start coughing up blood, you should see a doctor as soon as possible.
Likewise, if your symptoms get worse and worse and you have not started to improve after a week.7
Why do we get fevers?
A fever in adults is a body temperature over 38 degrees Celsius. For children, their temperatures can get higher, at 39 to 40.6 degrees Celsius.8
Along with the increased body temperature, you can also sweat and shiver as a result of a fever, have flushed skin, and feel weak or dizzy.9
A fever is a part of your body’s natural immune system response to an infection.
By raising your body temperature, your body can make it harder for the virus to replicate.
Elevated body temperatures also trigger mechanisms within your cells that encourage your immune system to take the appropriate action against bacteria or a virus.10
If your flu is mild though, your body could be able to fight it off without raising your temperature, so in that case, you would not get a fever.11
How long does the flu last?
Most people though will recover from the fever and other flu symptoms within a week, without medication.12
You may feel quite tired beyond the one week mark however.13
The best way to treat the flu
Usually you can treat the flu from home, with a lot of rest and water and herbal teas.
There are medications you can take to relieve the symptoms and to speed up recovery, though they are typically used in more severe cases or by people who are at risk of complications.
In most cases you can trust your immune system to fight off the infection.14
The flu is most infectious within the first five days. It is spread by germs from coughing and sneezing. These germs can live on your hands or on other surfaces for 24 hours.
So, to avoid spreading the flu, be sure to wash your hands with warm water and soap, use tissues to trap the germs when you sneeze or cough (or your elbow if you are caught off guard), and bin used tissues quickly.15
It is also worth regularly cleaning surfaces such as your computer keyboard, your phone, and door handles, to get rid of any germs.16
Another way to reduce the likelihood of getting the flu is through vaccination. Because immunity through vaccination does wane, it is recommended that you get vaccinated once a year.17
Last updated: 29 October 2020