Seasonal flu, which is medically referred to as influenza, is a highly infectious illness, which is spread through the flu virus. Affecting the upper airways and the lungs, it manifests itself by a sudden increase in bodily temperature and a feeling of pain and aching throughout the entire body. But how long does the flu last, and who is most at risk from it?

Sufferers can expect to have symptoms for up to a week or more, though some people can get over the illness within a day or two. This duration varies according to the severity of the strain of the flu as well as other factors.

Throughout this period, sufferers can expect to remain infectious throughout the majority of this period. However, it is important to stress that sufferers will be infectious a day before any symptoms actually show themselves, whilst primary infection can occur up to four days before any symptoms are felt.

Whilst this is the case for otherwise healthy adults, the elderly, those with weakened immune systems and the young could remain infectious for longer periods of time.

It is the young, the elderly and those with preexisting respiratory conditions that are most vulnerable. However, it is not so much that they are more vulnerable to infection, but more with the severity of the symptoms.

This can result in severe reactions, and as a result, there are a significant number of deaths throughout the winter period. Many countries suggest that you have a flu jab at the start of the winter season to help reduce the effects.

The flu virus can spread alarmingly quickly through the populous, as it is passed through the transfer of saliva, or simply through close bodily contact, no matter how brief. A handshake can be all it takes for example.

Whilst there is no clear answer to how long does the flu last, being that it does vary from person to person, it is advisable that you stay away from public areas, including work, for at least three days.