How not to get a cold

Keeping warm really can help you stay well, doctors say. And that's not the only surprising fact about beating winter bugs. Jeremy Laurance reports
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Indy Lifestyle Online

WRAPPING UP WARM CAN STOP YOU FROM CATCHING A COLD

There is a simple measure we can all take to avoid colds this winter. Buy a scarf.

Professor Ron Eccles, director of the Common Cold Centre in Cardiff, says: "As soon as the weather turns cold, I keep my nose warm. The nose dries out in low temperatures or in dry air conditioning, and respiratory viruses become trapped and start to reproduce. We should all wind scarves around our necks and over our noses."

This may be why we get more colds in the winter. For centuries, folklore has suggested a link between illness and the seasons. "Don't go and catch a chill," our grandmothers told us - and now science has proved a link between colds and the cold. When volunteers were chilled by sitting with their feet in bowls of icy water for 20 minutes, almost one in three (29 per cent) developed symptoms of a cold within five days. Among a second group who sat with their feet in empty bowls, less than one in 10 (9 per cent) fell ill.

The study by Professor Eccles and colleagues, published in the medical journal Family Practice this week, demonstrates the link between seasonality, the effects of chilling and infection.

YOU CAN HAVE A COLD WITHOUT KNOWING IT

The reason for the upsurge of illness each winter is that cold viruses are much more prevalent than we realise. For every person with a cold, there are two or three who have sub-clinical infections - that is, they have the virus in the back of their noses but they do not develop symptoms, and may never do so. The body's normal immune response keeps them in check.

During the summer, this works well and relatively few people who harbour cold viruses develop full-blown colds. But in winter the cold weather outdoors causes the blood vessels in the lining of the nose to constrict, a reflex mechanism to save heat. This reduces the blood supply to the nasal lining where viruses can gain a foothold and become established.

"The effect of the cold is that it reduces the flow of white blood cells, the body's immune response, cutting off the troops to fight the infection. The cold also slows the flow of mucus in the nose which is needed to trap the virus so you swallow it and destroy it in the stomach," Professor Eccles says.

So wrapping up well when you go out in winter is not just for softies. It is an effective way of warding off nasty bugs.

YOU MAY BE ABLE TO STOP THE INFECTION IN ITS TRACKS

A similar principle is employed by the latest anti-cold treatment to come on the market. Called Vick's First Defence, it is a nasal spray that makes no claim to cure colds but does claim to prevent them. It says it can reduce the chance of a full-blown cold by up to 50 per cent if taken at the first sign of symptoms, and can cut the severity of those symptoms by 40 per cent. So can you have half a cold? It appears you can. The treatment, which is not a drug, works by trapping the virus in a viscous gel, disarming it and helping the body to flush it out.

There are at least 100 cold viruses, and attempts to develop a single drug effective against all of them have failed, despite efforts made over the last half-century.

The new treatment targets the virus using physical rather than pharmacological means, by preventing it from penetrating the back of the nose. Trials on 400 volunteers have shown that if taken within two days of the appearance of symptoms, enough of the virus is prevented from entering the body to reduce the severity and length of the infection - to leave, in effect, half a cold.

Professor Eccles says: "I think the concept is interesting. The evidence for its effectiveness is not black and white, but it is supportive. Like all seven-day wonders we will have to wait for definitive results."

VITAMIN C ONLY WORKS IF YOU'RE A MARATHON RUNNER

One of the most widely used treatments for colds is Vitamin C. Yet there is no evidence that it works - except for those deficient in the vitamin, who should eat more oranges.

Linus Pauling, the chemist and Nobel Prize winner, popularised the idea of taking huge doses of Vitamin C to ward off colds in the 1970s. The suggestion captured the public imagination and sales of Vitamin C soared and have remained high ever since.

However, a review of 55 studies of Vitamin C by researchers from Australia and Finland found even daily doses of 2g - 33 times more than the recommended amount - failed to protect against colds. The only people who appeared to benefit were skiers, soldiers and marathon runners - those involved in extreme exertion in cold weather.

The authors concluded: "The lack of effect of prophylactic Vitamin C supplementation on the incidence of the common cold in normal populations throws doubt on the utility of this wide practice."

ECHINACEA WON'T HELP

The most popular preventive treatment for colds - the herbal medicine echinacea - suffered a blow to its reputation with the publication in July of a study showing it was useless in warding off infection.

Millions of pounds worth of products including tablets, creams and toothpastes containing echinacea are sold in Britain every year.

But when 400 volunteers were given three different preparations of echinacea for a week before and five days after being dosed with a cold virus, researchers found they were just as likely to develop a full-blown cold as those given a placebo.

The findings were published in the New England Journal of Medicine, and the authors, from the University of Virginia, concluded that the "putative active ingredients" of the herbal preparation "do not have clinically significant effects on the illness or infection".

Professor Eccles said the problem was that the name echinacea on a package did not bear much relation to what was inside. "The contents vary according to where the herb was grown, when it was harvested, which part of the plant was used, how the active ingredient was extracted, its concentration and how it was formulated. We need a standardised product."

KISSING IS FINE - BUT DON'T SHAKE HANDS

For effective measures against the cold virus it is better to focus on physical rather than pharmacological defences - such as the scarf.

Chest specialists know better than most how to protect themselves - and they are unlikely to shake hands with someone who has the sniffles. It is not coughs and sneezes that spread diseases, but hands.

The commonest way of catching a cold from an infected person is by shaking hands with them, or touching a surface they have touched (the cold virus can live on a door knob for hours) and then rubbing your eyes or mouth. This is a more reliable way of transmitting the virus than breathing near or even kissing them.

The virus travels in the respiratory system, so is lodged in the mucus at the back of the nose and throat. Only if you have a bad cough and some of the respiratory mucus becomes mixed with your saliva is there a risk of the virus being transmitted in a kiss. Colds are actually quite hard to catch - they depend on mucus from the respiratory tract of the infected person being transmitted to the respiratory tract of the person to be infected.

Traditionally we have assumed that this process is more likely to occur in winter because we are crowded into overheated spaces where we have closer physical contact with other people. But catching a cold, it turns out, has less to do with close physical contact than cold noses. If you want to protect yourself from marauding viruses this winter, keep your nose warm.

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