Baker points out that more than 200 viruses have been implicated as being the cause of the common cold. To complicate things further, the cold is a syndrome with a collection of features, rather than a specific disease with a single cause.
"Influenza viruses are also commonly identified in patients whose illness is described as a cold, showing how the common cold overlaps with mild cases of more serious illness. Unfortunately, it is not possible to vaccinate against a cold because of the large number of different viruses that cause it. However, influenza vaccination which prevents cases of serious influenza may also prevent some milder cases that would be labelled as a cold by some people."
Colds are seasonal. Most of the viruses occur in winter and spring. There are many theories about why this should be so; people may congregate indoors more in winter, the lower temperature and higher humidity of indoor air in winter may assist virus survival and transmission and winter conditions may make people more vulnerable to infection due to factors such as lower vitamin D levels and reduced immunity.
In the absence of a cure or vaccine, the best we can do is treat the symptoms. Baker recommends drinking plenty of fluids and resting at home. Over-the-counter products can tackle some of the unpleasant symptoms but, he adds, patients who are particularly unwell should see a doctor. Upper respiratory tract infections can be serious and result in more than 4000 acute overnight hospital admissions a year.
The advice on preventing transmission is to cover coughs and sneezes (with a tissue or sleeve rather than the hand), wash and dry hands regularly and stay away from work or school when infected.
The good news is that getting a cold will build up immunity to the specific virus that has caused it. "Unfortunately, so many different viruses can cause a cold so immunity to just a few of them doesn't help a great deal," says Baker.
There are a number of traditional remedies for colds, from chicken soup to alcoholic hot toddies.
Jaine Kirtley, spokesperson of the NZ Society of Naturopaths, says many of them do help, and are more gentle than some commercial medicines.
"A lot of medicines contain caffeine," she says. "It may stimulate you so you can go to work, but it's not going to help the cold at all. This is a real problem because the body is not fighting the infection. Two weeks later, you've still got the runny nose. It's terrible. Everybody wants instant results, but our bodies are not machines."
Kirtley describes colds as as the body's way of saying it needs to rest. We are particularly vulnerable to colds in the winter because chilly and damp conditions put more strain on the body's immune system. When we don't look after ourselves we get run down and we are more susceptible viruses.
"A cold is quite a good thing because it encourages you to slow down," she says. "It's better to have a few colds than a heart attack."
Natural way
Naturopath Jaine Kirtley says rest is the best way to get through a cold. Other treatments and protection against colds which she recommends include:
* Vitamin C
* Echinacea
* Zinc
* Manuka and eucalyptus oils
* Onion syrup
* Garlic, preferably raw or as a tea
* Cinnamon
* Avoid dairy products and sugary foods
