It is estimated that there are over 200 viruses that cause the common cold.

This large number of viruses has made the development of a single effective cold vaccine impossible thus far. The viruses cause infection by penetrating the mucous membrane in the nose. Most of these infections seldom cause anything more than normal cold symptoms although some can lead to more serious illness.

The common cold is the result of a viral infection within the nose and throat. It causes a barrage of symptoms (familiar to most of us) that include:

• A runny or blocked nose.
• Sore throat.
• Sneezing.
• Coughing.
• Some people may also suffer from a mild fever, headache, earache or tiredness.

The symptoms of flu come quicker than the common cold and can include the some or all of the above symptoms in addition to the following:

• Sudden fever of 38-40°C (100-104°F).
• Muscle aches and pains.
• Sweating.
• Feeling of exhaustion.
• Dry, chesty cough.

If you have a fever or high temperature of 38°C (100°F) and two or more of the following symptoms you may have H1N1 Flu commonly known as swine flu:

• Unusual tiredness.
• Headache.
• Runny nose.
• Sore throat.
• Shortness of breath or cough.
• Loss of appetite.
• Aching muscles.
• Diarrhoea or vomiting.

If you suspect that you may have swine flu then please seek advice from your pharmacist.

Viral infection

The viruses that cause the cold are spread by airborne droplets and through touch. A person carrying the infection may carry the virus on their hands after touching their nose and face, and can then transmit this through touch.

A carrier of the virus becomes ‘contagious’ a day or so before their symptoms first appear and for two to three days after the infection.

The cold virus can survive outside of the body for several hours and so hard surfaces such as door handles and telephones can harbour and transmit infection.

There are several myths that are not supported by clinical evidence. These include being exposed to cold temperatures or going outdoors with wet hair.

These myths also known as ‘old wives tales’ tend to come about due to the fact that colds are so much more common during the winter months. This is actually because the climate during the winter months, with low levels of humidity, suits the virus so much more than summer and spring time.

The common cold is also easily transmitted during winter months because people tend to spend more time indoors in enclosed spaces with others.

Treatment and prevention

There are a wide range of cold and flu remedies available at your local pharmacy. Most of these help relieve specific symptoms. Many contain painkillers that relieve the discomfort of a sore throat or headache, or decongestant ingredients that reduce the inflammation of the mucus membrane in the nose or throat.

There are many combination remedies that attack the main cold and flu symptoms.

Some simple tips for preventing cold infection include:

• Staying away from crowded and enclosed places where the risk of infection is greater.
• Washing your hands thoroughly after contact with anyone who has a cold to remove traces of the virus possibly transmitted through touch.
• Keeping rooms well aired.
• Using alcohol gel and wipes to clean surfaces and hands.

Many people now use vitamin C as a dietary supplement to help releive cold symptoms. Vitamin C has antioxidant and immune boosting properties.

Many vitamin C supplements are also combined with zinc because zinc is believed to have anti-viral properties.

It is thought that if you take zinc within a few hours of the onset of a cold it may help to speed recovery from the infection and reduce symptoms.

Research is still being conducted upon these claims.

A healthy diet is certainly likely to help prevent cold infections because it generally supports the immune system, meaning your defences against viruses will be stronger.