Influenza factsheet

What is influenza?

• Influenza or 'flu' is a viral infection that mainly affects the nose, throat and the lungs.
• There are two main types of flu that cause infection; influenza A and influenza B.  Influenza A is usually a more severe infection than influenza B and although influenza B tends to occur most often in children it can affect any age.
• Flu symptoms include the abrupt onset of fever, shivering, headache, cough, sore throat, aching muscles and joints. There is a wide range of illness ranging from minor symptoms through to pneumonia.  Flu symptoms are different from a cold as a cold is often limited to a runny nose, sneezing, watery eyes and throat irritation. The symptoms usually occur gradually and do not cause a fever or body aches.
• Usually what people call "gastric flu" is a gastrointestinal infection with another virus – usually norovirus or rotavirus.

Who catches influenza?

• Anyone can catch flu; the highest rates of infection are usually in school age children.
• Most influenza infections occur during the winter months.
• The amount of illness occurring each year varies, depending on the particular strain that is circulating. Some influenza viruses cause more severe illness than others. Hence in some winters people may be more unwell with flu than in other years.
• World wide epidemics (pandemics) of influenza occur from time to time and the impact of these can vary enormously. The most recent pandemic caused by H1N1 (2009) in 2009 was relatively mild, however, the most infamous pandemic was the Spanish flu of 1918-19 which killed over 40 million people world wide (more people than were killed in the 1st World War).

How do you catch influenza?

• Influenza is mostly caught by breathing in air containing the virus when an infected person coughs/sneezes or by touching a surface where the virus has landed and then touching your mouth or nose.

How infectious is influenza?

• Influenza is infectious and can spread rapidly from person to person.
  Some strains of virus are more infectious than others, or cause more severe illness.

What is influenza like?

• Influenza is worse than an ordinary cold. It usually starts suddenly with a high fever over 38.0°C which can last for 3-4 days. A dry cough, headaches and chills are common as are general muscle aches and pains. A stuffy nose, sneezing and a sore throat can also be present.  The fever tends to decrease after the second day when a stuffy nose and a sore throat become more noticeable.  Some children may also feel sick (nausea), or have diarrhoea.  Tiredness can last 2-3 weeks.

How serious is influenza?

• Most people recover completely from influenza in a matter of days or a week. For others, for example older people, pregnant women, those with other illnesses (such as chest or heart disease, or diabetes) and newborn babies, influenza can be a serious illness.
• Serious illness from influenza can be caused either by the virus itself causing a severe viral pneumonia, to a secondary bacterial infection causing bronchitis and pneumonia or to a worsening of any underlying chronic medical condition such as heart disease.

Can you prevent influenza?

• Vaccine is available to protect against flu. Each year a new vaccine has to be produced to protect against the flu viruses expected to be in circulation that winter and to boost the immune response.
• The vaccine is very safe and side effects are uncommon and usually mild.
  The vaccine is given in the autumn before the flu season begins. It is not recommended for everyone, but it is advisable for those likely to be more seriously affected by influenza. This includes:
• People of any age with chronic heart, lung, metabolic disorders (including severe asthma and diabetes), kidney problems or a lowered immune system due to treatment or disease.
• Pregnant women.
• Everyone aged 65 years and over
• Those in long stay residential care accommodation where influenza, once introduced, may spread rapidly.
• It is recommended that immunisations be offered to health and social care workers involved in the direct care of and/or support to patients and also anyone caring for a person in the at risk groups.
• Children and fit adults under the age of 65 years who are not in one of the groups mentioned above are not offered the vaccine as part of the national programme.

How can you reduce the risk of influenza transmission in schools?

• Keep children and staff that are ill away from school – they should remain off until they are symptom free.
• Wash hands frequently with soap and water and dry thoroughly
• Avoid touching surfaces (such as door handles) and then the face
• Cover your mouth and nose with a tissue when coughing or sneezing and dispose of used/dirty tissues in a bin – “Catch it, Bin it, Kill it”

How soon should a child be back at school after influenza?

• Influenza is most infectious when symptoms start until about 3-5 days later. There are no recommended times of exclusion for an infected child: a child should return once they are well enough.

How can you treat someone with influenza?

• Most people with the flu need no special treatment. Influenza is caused by a virus so antibiotics do not help unless there is a complication. Occasionally a special 'antiviral' medicine is given to people in the at risk groups or whose illness is getting worse.
• Someone who is ill with flu should keep warm, rest and drink lots of fluids to prevent dehydration.
• Paracetamol can be given to reduce the fever; aspirin must NOT be given to children under 16 years of age as it has been associated with the development of a severe neurological disorder called Reye's syndrome.
• It is best to stay at home while feeling ill with influenza as this reduces the chance of spreading the infection to others.