Fact Sheet: The common cold

What is a common cold exactly, and how is it different from the flu?


A common cold is an infection that develops over a few days. It is usually caused by a virus and generally begins with a sore or scratchy throat. Within a few days, more symptoms start: a blocked and/or runny nose, sneezing, coughing, sore throat and/or a headache. Sometimes you can have a mild fever and general aches and pains.

Even though a cold can make you feel really sick, if there is nothing else wrong, a cold will mostly get a lot better by itself within a week. The worst is usually over within three or four days.

Colds are very common, especially in children. It is not unusual for a child to pick up a cold at school, childcare or from home, between six and ten times a year. In babies and small children, the cold can cross over from the throat to the ear, and cause a middle ear infection (called "acute otitis media"). Adults get between two and four colds a year on average, usually in winter. You can find out how to protect yourself and your family from all these respiratory viruses here.

The viruses that cause colds and the flu (influenza) are not the same. The flu usually causes more severe symptoms than a cold. It can be hard to tell the difference, though, between a very bad cold and a mild case of the flu.

The flu usually starts more suddenly, with a high fever, shivering, and achy joints and muscles. Flu hits faster, harder, and lasts longer than a cold.
Seeing a doctor may be worthwhile if:

• you have a high temperature (over 38 degrees Celsius)
• your symptoms are severe or getting worse
• you have pain, especially in the chest or
• the symptoms do not get better within a week or so

The cold is an upper respiratory tract infection (URTI). The upper respiratory tract is the breathing system, around the nose and throat. Typical symptoms include a runny or blocked nose. Doctors call this rhinitis. Inflammation of the throat, causing a sore throat, is also common. This is called pharyngitis.




You can have other illnesses at the same time as a cold, such as:

• Sinusitis: an infection in the sinuses, which are little spaces under the bones around the nose. Pressure from having these blocked by infection can cause headaches
• Laryngitis: an infection of the voice box (larynx), which can make it hard to talk
• Tonsillitis: infection of the tonsils, which are on either side of the throat
• Bronchitis and pneumonia: infections that affect the lungs. These so-called "lower respiratory tract” infections are caused by other types of germs.

What helps against colds?

Colds are a part of life. The viruses that cause colds can quickly change over time, which means that having one cold does not give you immunity from colds in the future. That is also one of the reasons why there is no 'cure' for the common cold.

Your body will generally fight off colds without needing any help. However, there are a number of remedies or medicines you can try out that could help relieve the symptoms and discomfort.

These include, for example, bed rest and inhaling steam, as well as taking zinc tablets or herbal remedies containing echinacea. These cough and cold remedies have not been proven to work. There is some evidence to suggest, though, that some echinacea products from the coneflower called Echinacea purpurea might relieve the symptoms if they are taken at the beginning of a cold. You can read more about the research into echinacea here.

There is more evidence for things like paracetamol (acetaminophen) and acetylsalicylic acid (ASS). Children should not take ASS, as it can cause a rare but dangerous side effect.

People are often advised to drink plenty of fluids if they have a cold, but this has not been scientifically proven to help, at least not in children and teenagers. So there is no medical reason to drink more than feels comfortable when you have a cold.

Can antibiotics help?

Although many people believe that antibiotics can help with any infection, this is not the case. They only work for infections that are caused by bacteria. They are powerless against viral infections.

That is why antibiotics cannot usually do much against the common cold. Most colds are caused by viruses, although sometimes there is also bacterial infection. The streptococcal bacteria, for example, can cause sore throats (so-called "strep throat"). Antiviral drugs for colds are being developed, but these have not yet been thoroughly tested and approved for use.

Many trials have shown that antibiotics only have a limited effect in the treatment of common colds. Out of 10 people who do not take antibiotics and just rely on their own immune systems to help them get better, about 8 are over the cold in a week. Out of 10 people with colds who take antibiotics, 9 are better within a week. In other words, only 1 person out of every 10 who use antibiotics gets any benefit. At the same time, about 1 in 10 people who take antibiotics will get adverse effects from the medication. The most common of these include diarrhoea, nausea, vomiting, headaches, skin rashes and vaginal thrush (vaginitis).

If the runny or blocked nose symptoms are not better after a week, it is possible that a bacterial infection has developed. If that is so, antibiotics might be more likely to help. One possible sign of bacterial infection is if the mucus discharge from the nose is coloured.

Antibiotics are not very helpful against sore throats either, with the exception of bacterial infections like "strep throat". Sore throats also get better on their own within about a week. Around 4 out of 10 people (40%) will have got over a sore throat within three days. Antibiotics increase this to about 6 out of 10 people (60%). But here again, you need to take the same risk of adverse effects into account.

What about vitamin C?

Many people regularly take vitamin C tablets to prevent a cold, or take them when they have a cold to try to cure it. However, trials show that vitamin C cannot prevent the common cold in the average person, although it might lessen the amount of time you are sick just a little. Taking vitamin C at the start of a cold is not likely to relieve symptoms or shorten the illness. Very high doses of vitamin C can also cause side effects, especially diarrhoea. This can be a worse health problem than the cold, particularly for older people and young children. You can read more about research into the effect of vitamin C on the common cold here.

What can you do to limit the spread of colds?

The viruses and bacteria are spread to others from everything that has touched the mouth or nose. This includes cups and glasses people have been drinking from, as well as their hands and used tissues and handkerchiefs. These should not be left lying around on surfaces that other people might touch.

Every time a person with a cold sneezes or coughs, lots of tiny virus-containing droplets are sprayed into the air. If someone touches something that these droplets have landed on, the viruses could spread to their hands. When they then touch their own noses or mouths, they can get infected. This means that keeping your hands away from your face could help reduce your chances of getting a cold.


Author: Institute for Quality and Efficiency in Health Care (IQWiG)

© IQWiG (Institute for Quality and Efficiency in Health Care)