Influenza

What is influenza?

Influenza is characterised by a runny nose, sore throat, headache, fever and aching muscles and joints.

Influenza is a viral disease that usually strikes between October and May.

It lasts from three to five days and can be followed by fatigue for two or three weeks. It usually causes aching muscles and joints, headaches, cough and fever with a temperature of between 38^o and 40^oC.

Although it can become a much more severe illness, leading to pneumonia, nerve and brain damage and even death – such complications are rare.

Because it is a viral infection, it cannot be treated with antibiotics. Antiviral agents can reduce the severity and duration of infection, but these are generally prescribed only if there are concerns regarding complications of the infection or transmission of more severe strains of the virus. The best remedy is rest while drinking plenty of fluids.

It's possible to get vaccinated against influenza, which is especially advisable for the elderly and other people who are at increased risk of experiencing complications of flu. These include people with chronic heart, lung, kidney, liver and neurological diseases, people with diabetes, people with HIV infection and those who have an underactive immune system.

In 2009, a pandemic (global outbreak) of swine flu (H1N1 influenza A) was associated with high complication rates in pregnant women and pregnant women are now recommended to have a flu vaccine.

In the UK vaccination is recommended for:

• anyone over 65 years of age
• anyone with a chronic heart condition
• anyone with chronic respiratory conditions, such as asthma or COPD
• anyone with chronic kidney or liver diseases
• anyone with chronic neurological diseases
• anyone with an underactive immune system and those who live with them
• pregnant women
• residents of nursing or residential homes
• carers and healthcare workers who have direct contact with patients
• anyone who may otherwise be at increased risk.

What are the symptoms?

• Headache.
• Fever (38^o to 40^oC).
• Aching muscles and joints.
• Chest pains.
• Lack of appetite.
• Fatigue and weakness.
• A runny nose and sore throat.
• Dry cough.
• Restless sleep.
• Chills and shivering.
• Indigestion.
• Vomiting or diarrhoea.

What can I do?

• Step up your fluid intake – you lose a lot of liquids during a fever.
• Rest, preferably by staying in bed.
• Try to get plenty of sleep.
• If you have a cough, an over-the-counter cough remedy may ease your symptoms. The pharmacist is the best person to advise on this.
• Avoid smoking and drinking alcohol.
• Paracetamol (eg Panadol, Calpol) or aspirin (eg Aspro clear) will reduce fever and muscle aches. (Note that aspirin should not be given to children under 16 years of age, unless on the advice of a doctor.) Ibuprofen (eg Nurofen) will also relieve these symptoms. These painkillers are also found combined with medicines such as nasal decongestants in various over-the-counter cold and flu remedies. Ask your pharmacist for advice about which are most suitable for relieving your symptoms.
• Consult a doctor if the symptoms do not disappear after a week, or sooner if you feel worse.

How is influenza spread?

Influenza is a viral disease, which is passed from one person to another through the air. The disease infects the nose, throat or lungs. Droplets can contaminate the skin and frequent hand washing is advised.

It often breaks out as an epidemic, which quickly spreads from town to town and country to country. Typically, an area can have epidemic conditions for a period of four to six weeks before it eases off.

Are there different types of influenza?

Yes, there are three types of influenza.

Type A

The most serious type with the most acute symptoms. It is also the most common form, usually breaking out every two or three years. The 2009/2010 pandemic was caused by influenza A H1N1.

Type B

Similar symptoms to type A, but not as serious. The outbreaks happen every four to five years.

Type C

The mildest type, with symptoms similar to a cold.

How long will the influenza last?

Usually, influenza lasts three to five days. If it goes on for more than a week or if the symptoms are very severe, you are advised to consult your doctor.

A bad case of influenza has the potential to develop into a more serious condition like pneumonia or sinus trouble, and in rare cases it can be life-threatening.

Who is at risk?

Influenza can be dangerous to the elderly, especially those who live in residential homes where there is more risk of contracting the virus through contact with others.

People with lung and heart diseases are also more likely to develop complications due to an attack of flu. Those at risk are advised to get a yearly vaccination. Consult your doctor if you have any problems or questions.

Other important facts

• Both colds and flu are caused by a virus but the symptoms of influenza are usually more severe.
• Antibiotics have no effect against influenza.
• Damp or cold cannot cause influenza. However, sudden changes in temperature may cause the symptoms to appear more quickly.
• People are seldom infected by the same type of influenza twice because resistance develops within two or four weeks. However, the influenza virus constantly mutates into slightly different versions of itself, which is one reason why vaccination is sometimes ineffective. The vaccination also needs to be done yearly to keep up the person's level of immunity. The type of vaccination given each year changes slightly, as this is the ‘best guess’ vaccination to cover the likely type of influenza virus that will be most common that year.
• It's possible to pass on the infection the day before you develop the symptoms yourself. You can also pass on the infection until the day after your fever has disappeared.

Current evidence does not support a preventative effect of homeopathy in influenza and influenza-like syndromes. Vaccination should still be the preventive measure for patients at risk, ie those over 65 years and with heart or lung diseases.

Antiviral agents such as oseltamivir (Tamiflu) and zanamivir (Relenza) can shorten the duration of infection.

There are concerns that widespread use of such agents can encourage the emergence of resistant strains of virus. These agents are generally used therefore when there are particular risks of complications or to limit transmission of the more severe strains of the virus.

Despite the bewildering number of over-the-counter remedies for 'flu', all are symptom relievers only, and the number of active ingredients is quite small.

People taking other medicines should check with the pharmacist before taking a flu remedy in case of interaction between medicines.

References

Cates CJ, Jefferson TO, Bara AI, Rowe BH. Vaccines for preventing influenza in people with asthma (Cochrane Review). In: The Cochrane Library, Issue 1, 2000. Oxford: Update Software.

Demicheli V, Rivetti D, Deeks JJ, Jefferson TO. Vaccines for preventing influenza in healthy adults (Cochrane Review). In: The Cochrane Library, Issue 1, 2000. Oxford: Update Software.

Jefferson TO, Demicheli V, Deeks JJ, Rivetti D. Amantadine and rimantadine for preventing and treating influenza A in adults (Cochrane Review). In: The Cochrane Library, Issue 1, 2000. Oxford: Update Software.

Marrie TJ. Community acquired pneumonia. Clinical Evidence 1999;2:563-70.

Vickers AJ, Smith C. Homoeopathic Oscillococcinum for preventing and treating influenza and influenza-like syndromes (Cochrane Review). In: The Cochrane Library, Issue 1, 2000. Oxford: Update Software.