Updated 2013

Seasonal influenza

Introduction

What are flu symptoms

How can I catch flu

How can I prevent flu

You can also reduce your risk

Where is flu found

Can flu be treated

Flu vaccine

Who shouldn't have the vaccine

Reactions to the vaccine

More information (links)

Introduction

Influenza, usually known as flu, is a viral illness which affects the chest and upper respiratory system. It causes a sudden, feverish illness. Most people recover in one or two weeks.

What are flu symptoms?

Fever (a high temperature), chills, headache, cough, tiredness, loss of appetite, sore throat, blocked nose, and muscle and joint pain are all classic flu symptoms. Although flu is usually self-limiting, it can lead to complications such as pneumonia.

Flu can also make existing medical conditions much worse, which can be very dangerous or even fatal. Older people, the very young and anyone with serious medical problems, such as asthma, diabetes or heart disease, are particularly at risk becoming very ill.

How can I catch flu?

Flu spreads when an infected person coughs and sneezes, producing respiratory droplets. If you breathe in these droplets or touch surfaces contaminated with them, you are likely to get flu. Crowded, enclosed environments make it easier to catch the disease. Hands can also be contaminated and the flu virus can survive for up to 24 hours on hard surfaces.

How can I prevent flu?

The flu vaccine is one of the most effective ways of preventing flu. All travellers aged 65 years and older or those with specific medical problems (see Flu vaccine section) should be offered the flu vaccine each year.

You can also reduce your risk by:

•  Avoiding crowds and close contact with anyone with symptoms. The respiratory droplets do not travel more than 2 metres.

•  Covering you mouth/nose with a clean tissue when you cough or sneeze.

•  Disposing of dirty tissues safely.

•  Washing your hands frequently.

•  Keeping hard surfaces clean.

•  Not travelling if you have any flu symptoms.

•  Face masks are not generally recommended.

Where is flu found?

Seasonal flu is present all over the world. In the northern hemisphere the flu season is usually from November to March and in the southern hemisphere, from April to September. In tropical countries, the flu virus may be present throughout the year. The peak time in the UK for flu is December to March, although it can occur outside this period.

Flu can affect all age groups. However, the risk of illness in different age groups can vary from year to year, depending on the type of flu virus circulating. Up to date information on seasonal flu is available from the World Health Organization (WHO).

Your risk of catching flu during travel depends on your destination, the time of year, what you are planning to do and how long you are away.

Travellers can be at risk during the summer months, particularly if travelling in large groups including tourists from areas of the world where flu viruses are currently found. Crowded conditions such as festivals, cruises and pilgrimages such as the Hajj increase the spread of infection.

Can flu be treated?

Your doctor can prescribe drugs to treat flu, such as oseltamivir (Tamiflu®) or zanamivir (Relenza®). However, these medicines are only recommended if you are at risk of complications and start taking the drugs within 36-48 hours of your first symptoms. If you are normally fit and well, you should rest, drinking plenty and take pain relief such as paracetamol, which will also help bring down your temperature.

 

Flu vaccine

The aim of the flu vaccine programme is to protect anyone likely to get seriously ill or die if they catch flu. Flu vaccine is available every year from September. It’s free - if you are 65 years and older or have any of the medical problems listed below:

• An immune system not working properly (immunosuppression) due to illness or a treatment such as chemotherapy.

• Chest complaints like asthma or chronic obstructive pulmonary disease.

• Diabetes.

• Heart conditions such as ischemic heart disease or heart failure.

• Liver and kidney problems.

• Long term neurological illness, such as Guillain Barré syndrome, which affects the peripheral nerves.

 

Pregnant women and poultry workers are also offered vaccine.

If you are going to work or have a lot of contact with poultry while you are abroad, you should ask your GP or practice nurse for the flu vaccine.  This reduces the risk of bird (avian) flu mixing with seasonal flu and creating a new, potentially pandemic virus. Flu viruses change (mutate) every year. This means flu vaccines are adapted every year to ensure they protect against the flu viruses predicted for that year. WHO looks at all the research and information on flu and advises which flu viruses will be a problem that year.

Flu vaccines are prepared using virus strains recommended by the WHO and are grown in hen’s eggs. They do not protect against bird (avian) flu.

Most flu vaccines are given as an injection into the muscle of your upper outer arm or sometimes in young children into the outer thigh muscle.

Current vaccines give up to 80% protection against flu. This is thought to last for approximately a year, although it may be shorter for older people. After vaccination, protection usually takes 10 to 14 days to develop.

Who shouldn’t have the vaccine?

Very few people are unable to have the flu vaccine. It should not be given to anyone with a severe, life threatening reaction to a previous flu vaccine (or any of the vaccine’s ingredients) or to hen’s eggs. As with any vaccine, if you are unwell, especially with a fever, you should wait until you have recovered before having the flu vaccine.

Reactions to the vaccine

You may have a temporary reaction such as a sore, swollen arm. Fever, headache muscle aches and tiredness are less common reactions. Very rare side effects include: seizures (fits), nerve pain and numbness/tingling of the skin.

A severe, life threatening allergic reaction called anaphylaxis can occur after any vaccine. This is extremely rare and usually only happens after flu vaccine because of severe egg allergy. You must tell your doctor or nurse if you have ever had a reaction or allergy to eggs before you have any vaccines

More Information:

Health Protection Agency: Seasonal Influenza

NHS Choices: Seasonal Flu.

World Health Organization: Seasonal Influenza