How do you catch a cold?
The cold virus spreads by droplets in the air and on surfaces, and enters your body through the mouth, eyes and nose.
There are more than 200 cold viruses in total. The main culprits are rhinoviruses, which are responsible for 30-50 percent of colds in adults. The good news is that we catch fewer colds as we get older because our immune system has learned how to fight off the ones we’ve had before.
Scientists don’t yet know why we have more colds in winter than in summer, but they’re working on it. One recent theory is that our noses are colder at this time of year, and each time we breathe in, the lining of our noses cools, reducing the effectiveness of our defence system in that area. And that makes us more prone to infection.
You’re also more likely to catch a cold if you’ve just been through a major event such as marriage, a death in the family or losing your job. Happy, calm people are less likely to be unwell than those who are anxious, angry or depressed.
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Why do you feel ill with a cold?
Interestingly, when you have a cold your immune system is responsible for making you feel ill. It responds to the cold virus by releasing substances called inflammatory mediators, including histamine, interleukins and prostaglandins, and they are what cause the actual symptoms of a cold.
- your blood vessels dilate (making your nose bunged up) and leak fluid
- mucus gland secretion increases, which is why your nose runs
- your sneeze and cough reflexes are triggered
- pain nerve fibres are sparked off, making you feel aching and weak.
"When the virus infects cells, it sets off a chain reaction," explains Professor John Oxford, the UK's top expert on influenza and Emeritus Professor of Virology at the University of London. "You get a sore throat because the virus is replicating in the cells in the throat. Immune cells are attracted to the area to fight off the virus, causing slight swelling, and that’s when you get a sore throat. We’re at the edge of learning here, and there’s a lot of new knowledge coming out."
It seems we don’t all react in the same way to the same virus. "We do quite a lot of work where we get volunteers together in a hotel and infect them with the same virus, and we get a terrific variety of symptoms," explains Professor Oxford. "We don’t know why this is. It could be related to genetics - it’s something we’re working on. If we could find the answer to that it would be ace."
How to boost your immune system
How to avoid catching a cold
Coughs and sneezes really do spread diseases, but recent research from the University of Virginia found that the cold virus can survive on surfaces for 48 hours. So you can touch the TV remote control/fridge handle/door knobs up to two days after your sneezing other half last did so, and pick up the virus on your finger tips.
Catching a cold from your loved ones isn’t inevitable, although home is one of the most common places to pick up the virus. "You can take some preventive action by using what’s called social distancing," says Professor Oxford. "It means if your partner has a respiratory infection, just keep maybe six feet away, so if they do cough you probably won’t be infected so easily. Sleep in another room, don’t sit with your arm around them, just keep your distance.
"You should also increase your hygiene levels," he suggests. "A lot of these infections are transferred by touch. If you cough on a cup, someone else touches it and then touches their mouth, they could be infected. Make sure all your cups, plates and cutlery are washed at a high temperature, and be sure to wash your hands well and you can start breaking the chain of transmission. There’s also some evidence that things like First Defence can help." Wiping all those communal surfaces – the TV remote, telephones and handles – with an anti-bacterial wipe is worthwhile too."
How to feel better with a cold
Short of living like a hermit through the cold season, the chances are that you’ll pick up at least one cold. So do you hot-foot it down to the chemist, make your own remedies, or tough it out? Professor Oxford votes firmly in favour of making yourself feel better. "I’m not sure if there’s any truth in the old wives’ tales, like feed a cold, starve a fever. When those observations were first made, there wasn’t very much you could do about anything. Now there is."
Nor is he convinced that it’s advisable to try and 'sweat it out'. "We know that bacteria don’t replicate in high temperatures, but I think the feeling at the moment is that we keep the afflicted person happy and comfortable. Take something quite simple, like paracetamol and it will bring your temperature down and you’ll feel more comfortable.
"There's nothing wrong with an aspirin and a hot toddy. My suggestion would be honey, to sooth your throat, lemon, hot water and a dash of whisky if you like, and perhaps an aspirin or paracetamol."
The big question, though, is whether anything will make your cold shorter. "There isn’t anything at the moment," says Professor Oxford. "But there are some new drugs coming along. I would be surprised if there’s not something pretty effective in the form of a tablet for instance, in the next four years." There’s something to raise a glass of hot toddy to.
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How to avoid catching a cold on a plane
The risks of picking up a virus (or a bacterium) on planes have been studied by a number of researchers over the years, but it’s a subject that is shrouded in urban myth. Modern aircraft do recirculate a lot of the air in the cabin – rather than take in fresh – but it passes through very efficient HEPA filters that manufacturers claim remove at least 95% of airborne microbes. And, contrary to what you may have heard, pilots don’t routinely shut down fresh-air intake to save fuel; indeed in many planes they can’t adjust it at all.
There isn’t much you can do about breathing the same air as hundreds of other passengers, but watch where you sit and what you touch: bugs can lurk on all sorts of surfaces too. Research by an American microbiologist, who took swabs on more than 20 planes, suggests window seats are less hazardous from a viral point of view than aisle ones. And try to avoid going to the loo, or riffling through the magazines in the pockets in front of you, as he found both were heavily contaminated with bacteria and viruses.
Other research suggests that the biggest risk comes from people in your row. If one of them has a cough or cold, you are far more likely to catch it than if they are sitting in front or behind. So book your family into the same row(s) when you check in. Wash your hands when you get the chance, or use an antiseptic gel (although these are often not as good as soap for many viruses).
How to avoid a Christmas cold
It’s just what you don’t want for Christmas – a red and runny nose, a sore throat, and a head that seems to be stuffed with cotton wool. It can feel as though this unwanted gift comes every year at this time, but there are steps you can take to reduce your risk of catching the Christmas cold.
Christmas is a great time to spoil the youngest members of your family, and it’s hard to resist hugs and kisses when your grandchildren come round. Be careful, though. Because children are too young to have build up immunity against cold viruses they can be walking reservoirs of one of the 200 or so cold viruses we know about.
Before any little ones come to visit – or you visit them - ask their parents to check them for signs of cold symptoms. If they’re sneezing and have runny noses, they could probably infect you. Ask if they could come to visit when they’re feeling better, and less contagious. School children have seven to 10 colds a year, but adults generally only have between two and five colds each year, as they have built up immunity over the years.
It isn’t just grandchildren with colds you should be avoiding – friends of your own age can pass on their cold virus too.
As we grow older, our bodies go through many bouts with cold viruses. As a result our immune systems learn how to tackle the different viruses, so we do get better at fighting them off.
However, you still may not want to risk a Christmas cold. Check with friends if they have a cold, and let them know if you have one, before you visit.
10 ways to avoid catching a cold
1. Wash your hands
Wash your hands after being in a crowded place or in the same room as someone with a cold. This really works. A survey published in the American Journal of Preventive Medicine showed that episodes of colds and flu among 1,442 naval recruits at a training centre in Great Lakes Illinois almost halved after they were commanded to wash their hands more frequently.
The old theory about colds was that cold viruses were spread through the air, carried on tiny droplets of moisture that were then breathed in by other people. This is certainly one method of catching a cold, but experts now believe that many or even most colds are passed on via hands.
2. Avoid touching your nose, mouth and eyes
We touch our nose, mouth and eyes many times a day without realising it. Once the virus is on your hands it's all too easy to transfer it and tears drain from the eyes via a duct into the nose so virus can easily spread from the eyes to the nose.
During a cough or sneeze, 40,000 infected droplets may be expelled as far as 30 feet. Some of these droplets will be deposited on objects, where the virus may survive for up to three hours, to be picked up by anyone who touches the object.
Door handles, handrails on public transport, light switches and crockery are common culprits. You can also pick up cold virus by shaking hands with someone who has recently blown their nose.
3. Wear gloves on public transport
We often pick up colds from people we have never met so wear gloves when you travel on public transport. This might seem a bit over the top but it is very easy to pick up cold virus from handrails on the bus or tube.
4. Wrap up warm
Your granny was right: you need to wrap up. In an experiment at Cardiff University's Common Cold Centre 90 volunteers spent 20 minutes with their feet in cold water and, surprise, surprise: 29 per cent developed cold symptom within five days compared to 9 per cent of the control group who simply dangled their feet in an empty bowl.
5. Cover your nose
When wrapping up don't forget your nose - you should cover it with a scarf when the weather is cold. Professor Ron Eccles, former director of the Cardiff Cold Centre (which closed in 2017), said that viruses multiply in the cells that line the nose, and they breed faster when the cells are cool.
Take a walk to boost your immune system: even on a cold day it still helps. Again it is to the USA that we have to turn for the relevant research.
A study published in the American Journal of Medicine examined the risks of catching a cold among a group of post-menopausal women over a 12 month period. Their findings revealed that the women who walked for 45 minutes five times a week reduced their chance of catching a cold
7. Try to avoid stress
Banish stress. It might be easier said than done, but it really seems to help. Researchers at the University of Pittsburgh asked 276 healthy volunteers about the stresses in their lives, and then deposited cold viruses in their noses. Those who had reported chronic stress (especially personal difficulties with friends or relatives) were more than twice as likely to become ill with a cold. It seems that chronic stress affects the immune system, and makes people less resistant to infection.
8. Get some sleep
A small study carried out in 2015 found that lack of sleep was associated with an increased risk developing a cold. The volunteers who took part and had only five hours sleep were more likely to catch a cold than those who slept for more than seven hours a night.
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