Having a cold is a miserable experience—no doubt about that. Snuffling, sneezing, coughing, and feeling exhausted—we’ve all been there. Colds, however, are not just unpleasant—they present a very real public health problem. Here’s how to stop a virus before it starts, with everything you need to know about them, too.
A cold is an infection of your upper airways, caused by a virus. Around 50% are caused by the human rhinovirus (HRV). HRV belongs to the Picornaviridae family. It is an RNA virus whose genetic makeup has been extensively studied. The remaining colds are caused by other viruses such as the respiratory syncytial virus (RSV), parainfluenza and the corona virus (yes, like the one you’re hearing about in the news).
Nope. These viruses were first identified in the 1950s, but despite 60 years of research, sadly there is still no cure! In that time we sent a bunch of people to the moon, and designed an Instant Pot and figured out a way to have it delivered to our home in a day.
The coating of the viral cell wall—the capsid—contains several specific capsid proteins. These have a high propensity for genetic mutation—which is why new infections are common, and producing a vaccine has so far not been possible.
Once the HRV virus lands on the cell surface, such as the skin lining the inside of your nose, it attaches to the host cell, gains entry, and reproduces inside the cell to produce more viral particles. The host cell then ruptures to allow the new viral particles to escape and these are then ready to attack further host cells.
Catching a cold has nothing to do with feeling cold!
You catch the virus by either breathing it in, by skin to skin contact or by touching an object harboring viral particles on its surface.
The virus can live outside the body for several days in the correct environmental conditions and up to two hours on a skin surface. It usually enters the body through the nasal passages—not through the mouth.
Viral transmission takes place very easily.
- In one experiment, 18 subjects—artificially infected with HRV—played card games for 12 hours with their non-infected opponents. By the end of the study period, 56% of the 18 opponents were now infected.
- In another study, subjects were artificially infected with HRV. The virus was then detected on 40% of their hands and 6% of articles found in the home.
Mind that playing cards for 12 hours straight may cause worse problems than catching HRV. We recommend spending that time cooking stew in an Instant Pot.
The incubation period for the HRV virus is just under 2 days. Symptoms are at their worst days 1-3, often last 7-10 days, and can last 3 weeks.
The most common symptoms are a sore throat, runny nose, runny eyes and feeling lethargic and unwell. Children often have a fever, but this is not so common in adults. Children aged under 2 have 4-6 colds per year, whereas adults have on average only one per year.
Most colds are mild but debilitating. They most often infect your upper airways, however, although sometimes HRV can have more serious consequences, causing exacerbations of asthma, bronchiolitis and pneumonia.
Doctors may find it difficult to be sure of the diagnosis, as several other conditions can present with similar symptoms.
Allergic rhinitis (hay fever) causes a runny nose with sneezing, but a sore throat is unusual. If the throat is very sore, this raises the possibility of streptococcal pharyngitis (bacterial). Facial pain and nasal discharge occur when the sinuses have become infected. Similarly, infection of the eardrum produces severe ear pain, which may follow on from a cold—with an episode of otitis media.
One common difficulty is how to distinguish a common cold from an attack of influenza—”flu” caused by the influenza virus. Generally, people suffering from flu feel weaker and look sicker. They usually have other symptoms such as headache, joint and muscle aches and pains, fever with chills and sweats.
An attack of flu can be very serious for the elderly or for people who have a lowered immune system. It’s important with a serious systemic illness not to miss a potentially life-threatening condition such as meningitis or septicaemia.
The body has a complex immune system. Cells called macrophages are circulating all the time in your bloodstream. These recognize foreign particles and destroy them. However, if the virus is multiplying rapidly, the numbers rapidly overwhelm the macrophages. Other white blood cells called B-lymphocytes and T-lymphocytes are summoned.
B-lymphocytes attach to the virus and produce antibodies which kill the virus. T-lymphocytes kill virus-infected cells. Small numbers of B and T lymphocytes persist which remember the virus and are quick to attack the virus next time if you are re-infected.
The symptoms of the disease process reflect what is happening inside the body. The presence of the virus leads to an increase in body temperature. The virus cannot survive unless conditions are favorable, and so the rise in temperature is part of the body’s response to defeat it.
The immune system works by signaling different cells and cell processes using chemical messengers—called cytokines. The defence process is called inflammation. The symptoms of inflammation are warmth, redness, swelling and pain.
When you get a cold, there is a lot of inflammation in your nasal passages and upper airways. Blood vessels in your nasal passageways dilate, and excess mucus is produced. This is why you sneeze, your nose runs, your eyes run, and you cough.
However, if you have a mild dose of infection you may not even know you have been ill. This is called a subclinical infection.
Smokers seem to be more susceptible to colds. This is because their airways are already inflamed from the irritant effects of cigarette smoke. When the HRV then appears on the scene, this additional threat is too much to cope with, and the virus can take hold.
Lack of sleep may increase susceptibility to colds. In a 2015 study reported in the journal Sleep, a group of volunteers were artificially infected with a cold-causing virus and then monitored for cold symptoms over the next few days. Subjects who slept less than 5 hours per night were 4 and a half times more likely to catch a cold than those who slept 7 hours per night.
Colds are much more common in babies and small children. Being in the company of other small children is a risk factor as this is a breeding ground for infections. Breastfeeding, if possible, offers a distinct advantage because there are antibodies in breast milk. Regular hand-washing has been shown to help reduce viral transmission. Wash and dry your child’s hands regularly throughout the day and before mealtimes. Germs collect on dummies, doorknobs, work surfaces, and telephones, for example, so keep all these surfaces clean. Wash your baby’s toys regularly using a mild detergent. Don’t smoke around your baby.
Vitamin D deficiency seems to be associated with an increased frequency of catching a cold. In fact, vitamin D deficiency is also surprisingly common. Around 1 in 5 UK adults and 1 in 5 children are vitamin D deficient. Vitamin D is made in the body after exposure to sunlight. In the winter, when days are short, vitamin D levels may be depleted.
In a 2018 study reported in the British Medical Journal (BMJ), data from 25 randomized controlled trials including 11.321 participants, concluded that taking vitamin D supplements daily, or weekly, reduced the risk of acute respiratory tract infections. The results were most pronounced in people who had the lowest vitamin D levels.
Vitamin D is found in oily fish, red meat, liver, eggs and in fortified cereals.
Vitamin D supplements are recommended in babies and small children. Also in adults who are at risk, for example, the elderly or people who live in institutions.
Lack of exercise is linked to an increased risk of catching a cold. In a 2011 study in the British Journal of Sports Medicine, people who exercised five times or more per week had almost a 50% reduction in the frequency of colds. Fitness keeps your immune system in good shape. Inactivity does the reverse.
Being overweight or obese also increases your susceptibility to many different types of infections. Obesity is associated with metabolic syndrome. This is a complex condition in which your body is resistant to the hormone insulin. As a result, blood sugars remain unnaturally high. Your body is in a state of chronic inflammation. Your immune system is continually being activated, and overall, your cellular defence mechanisms are weakened.
Stress has been proven to increase susceptibility to colds. People with higher exposure to stress have been shown to have higher levels of glucocorticoid receptor resistance (GCR). This results in an inability to switch off the process of inflammation.
Moreover, people who are stressed have higher levels of cytokines, which are directly responsible for many of the typical cold symptoms. Chronic stress can make people more susceptible to colds.
It’s certainly true that all the parameters which increase the likelihood of getting a cold should be reversed. This means: stopping smoking, getting enough sleep, avoiding vitamin D deficiency, losing weight and maintaining a healthy weight, and getting regular exercise.
Despite considerable research, there is little evidence that most attempts to prevent the spread of cold-causing viruses are effective.
Medical studies have examined the effectiveness of control measures such as screening at entry ports, isolation, quarantine, social distancing, barriers, personal protection, and hand hygiene. The only measure which reduces transmission is regular hand washing.
Not clear. One 2012 randomised controlled study reported that taking Echinacea (3 x 0.9ml drops), four times a day for 4 months, reduced the number and length of a cold, by 26% compared to a placebo. However, research has not confirmed Echinacea to be effective in treating a cold when it presents as an acute illness.
Having a cold makes you feel lousy. However, unfortunately, there is still no quick fix remedy. A cold is caused by a virus and so an antibiotic will not be effective. Antibiotics kill bacteria only.
Antiviral medicines do exist but these are not required for most people most of the time. Because the virus mutates regularly many antivirals are also unlikely to shorten the illness.
When you have a cold you need to be kind to yourself and treat your symptoms.
- Rest – You may not feel well enough to go to work. Put your feet up and get plenty of sleep if you can.
- Drink plenty of fluids – keep well hydrated. Any fluids are good but avoid alcohol.
- Take acetaminophen – the adult dose is 2 x 500 mg tablets four times in a 24-hour period.
Take ibuprofen (assuming you are medically suitable, and for example, you have not had any indigestion/gastritis or peptic ulcer from taking ibuprofen or other nonsteroidal anti-inflammatory (NSAID’s) drugs.) The adult dose is 2 x 200mg tablets, three times a day. This will help reduce your temperature and relieve pain.
This will also relieve pain: You can take acetaminophen and ibuprofen at the same time.
- Try steam inhalations for blocked nose and sinuses. You do this by pouring boiling water into a bowl, covering your head with a towel and breathing the steam in deeply through your nose. Take care not to scald yourself with the hot water.
- Use a Vicks inhaler and/or a vapor rub on your chest. Menthol soothes irritated nasal passages.
- Have hot baths and showers—again the steam and the heat are soothing.
- If your throat is sore try gargling with saltwater. Just mix half a teaspoon of salt in a cup of water, gargle and spit it out. Do this several times and repeat during the day.
- Prop yourself up with extra pillows.
Consider taking a decongestant. Most of these contain antihistamines which may make you feel drowsy. This is not a bad thing if you are having trouble sleeping because of your cold. Take care as some may contain paracetamol and you don’t want to overdose. Speak to your pharmacist if in doubt. Decongestants are not advisable for example for children aged under 6, diabetics and people on various other medicines.
- Don’t smoke. This will make your symptoms worse.
- Don’t take cough medicines. Your cough is a much-needed reflex to stop mucus and debris getting into your lungs. Cough medicines are not likely to be effective. The best advice is to drink honey and lemon, Squeeze half a lemon into a cup. Add 2 teaspoons of honey and top up with boiling water. Stir well. Repeat as necessary.
There is no evidence that taking vitamin C while you have a cold is therapeutic. In one study, researchers found daily vitamin C during an episode, shortened the duration of the illness in adults by approximately one day. Foods naturally rich in vitamin C include citrus fruits, cabbages, greens and potatoes.
Yep. Mom’s always right. Chicken soup really is good for colds. A study in the journal Chest looked at the movement of white blood cells called neutrophils when combined with soup. The cells exposed to chicken soup showed significantly less movement, which suggested anti-inflammatory properties. “Chicken soup contains certain chemicals that may turn down the level of inflammation in your nasal passages from a cold,” says Dr. Amesh A. Adalja, MD, FIDSA, Senior Scholar at Johns Hopkins Center for Health Security. Beyond that, chicken soup is packed with nutrients and feels good on a sore throat.
Garlic, honey, elderberries, and probiotics help too.
Efforts continue to find a cure for the common cold, but these have so far been elusive.
Researches at Imperial College, London, have announced some promising results about a new chemical compound, IMP-1088, which stops the rhinovirus reproducing. It inhibits an enzyme called N-myristoyltransferase, which all rhinoviruses need to survive. So far this has only been tested in a laboratory setting and not on humans, but it looks like it may provide an effective remedy.
Dr. Deborah Lee is a medical writer at Dr Fox Online Pharmacy.
And to avoid being sick at all, don’t miss this essential list of the 50 Unhealthiest Things That You Touch Every Single Day