Colds and flu (influenza)
Colds and flu (influenza) are different illnesses caused by different viruses.
Colds are very common. Colds affect the nose, the throat and upper airways and common symptoms include coughing, fever, sore throat, sneezing, blocked or runny nose and general chest congestion. There are more than 200 different viruses that cause colds.
The flu is a viral infection affecting the nose, throat and sometimes lungs. Symptoms of the flu can include fever, sore throat, muscle aches and general soreness.
Its symptoms tend to be more severe and last longer than those of the common cold. The flu can also lead to complications, such as pneumonia.
Three different types of influenza viruses infect humans - types A, B and C with A and B causing major outbreaks and disease. Flu is mainly caused by types A and B and rarely type C influenza. Only types A and B cause major outbreaks, while type C can cause an illness in children similar to the common cold. Influenza A viruses are found in many species although water birds are its natural host. Types A viruses may include Avian (Bird) flu and H1N1 (Swine) flu. Influenza B virus is primarily a human disease.
There is an annual vaccination available for the flu and it's recommended for the elderly or those with chronic illnesses. Flu viruses do change over time and immunity from vaccinations is only temporary, hence why annual vaccinations are suggested.
Good hygiene is one of the most important ways to help prevent colds and flu from being caught and spread.
Other ways to help prevent flu can include antiviral medicines, although these are only recommended for preventing flu if you have been exposed to the flu in the previous 48 hours. While Antibiotics only work for bacterial infections and will not work on colds and flu which are caused by viruses.
What causes colds and flu?
Colds and flus are viral infections that can be caught at any time of the year, not just in winter, although they are more common during the winter months.
Typically they spread through close contact with someone who is infected. With a cold or flu when you sneeze or cough, tiny droplets of fluid containing the virus are dispersed through the air. These droplets spread and other individuals around you breathe in these cold and flu droplets.
These tiny droplets of fluid can also land on surfaces. Anyone who touches these surfaces can also catch a cold or flu if they pick up the virus on their hands and then touch their nose, mouth or face. This is why washing your hands is important in minimising the spread of colds and flu.
Cold and flu symptoms
Symptoms of a cold can include sore throat, fever, sneezing, blocked or runny nose and/or coughing. When you have green or yellow mucous flowing from your nose, this is a good sign that you body has an infection. If these aren’t any better after after 10 days, or you get worse, then we recommend you visit your local GP.
Flu or influenza symptoms include fever and chills – running hot and cold, chesty cough, headaches, exhaustion, body and muscle aches, sore throat, upset stomach and diarrhea, sneezing, difficulty sleeping, rash, and general loss of appetite.
Symptoms of a cold include:
- runny nose – beginning with clear mucus that develops into thicker, green mucus as the cold progresses
- blocked nose
- sore throat
People with a cold may also suffer with a mild fever, earache, tiredness and headache. Symptoms develop over one or two days and gradually get better after a few days. Some colds can last for up to two weeks.
A cold is most contagious during the early stages, when the person has a runny nose and sore throat.
Flu usually comes on much more quickly than a cold, and symptoms include:
- sudden fever of 38-40C (100-104F)
- muscle aches and pains
- feeling exhausted and needing to lie down
- a dry, chesty cough
A person with flu may also have a runny nose and be prone to sneezing, but these are not usually the defining symptoms of flu.
Flu symptoms appear one to three days after infection and most people recover within a week, although you may feel tired for longer. A severe cold can also cause muscle aches and fever, so it can be hard to tell the difference.
Whether it’s a cold or flu, get medical help if you either:
- have a chronic condition such as asthma, diabetes or heart disease
- have a very high fever as well as an unusually severe headache or abdominal or chest pain
Diagnosing colds and flu.
Generally healthy individuals won't need to see a doctor to diagnose a cold and your immune system will fight the infection. Symptoms will likely clear up in 7-10 days without any treatment. However, if symptoms last longer than 10 days we recommend your see your doctor for a face-to-face appointment or if you experience any of the following - a persistent cough, chest pains or difficulties breathing. Or if you have a long term medical condition or are pregnant we would also recommend you visit your GP as they may want to prescribe antiviral medication.
Colds and flu treatments
Most people get better by themselves after 7-10 days without any treatment. But there are things you can do to help you get better faster and these include things like:
- rest and keeping warm;
- consuming plenty of water and other non-alcoholic fluids;
- plenty of fruit and vegetables;
- avoid cigarette smoke;
- inhaling steam from a hot bath or shower to relieve a blocked nose.
If you are suffering a sore throat you try the following remedies:
- gargling warm salty water
- drinking hot water with honey and freshly squeezed lemon juice or
- your mum’s favourite - chicken soup.
Colds and flu medication and treatments
There are a number of over-the-counter medicines that can assist in relieving cold and flu.
Paracetamol can be used to relieve pain and fever in adults and children over two months. However, it is important to ensure you have the correct dosage for children which is based on their age and weight. If you are in unsure please contact your local doctor or chemist.
Ibuprofen can be used for pain and fever in adults and children of three months and over who weigh more than 5kg. it is important to ensure you have the correct dosage for children which is based on their age and weight. If you are in unsure please contact your local doctor or chemist.
Decongestants and saline nasal sprays or drops can be used to relieve a blocked nose. They should only be used for a maximum of 4 or 5 days. Only use saline nasal sprays or drops in children younger than six months and prior to using a decongestant please check with your doctor or pharmacist if it is safe to use.
Cough and Cold medicines
Cough and cold medicines can be used but there is insufficient evidence as to whether they work or not. Cough and cold medicines are not recommended for children under six. Please seek advice before giving cough and cold medicines to children aged between 6 and 11 years of age. Cough and cold medicines often contain paracetamol, so it is important to check the label and avoid ‘doubling up’ with other medicines that also contain paracetamol.
Antibiotics do not cure a cold or flu and they will not assist in relieving symptoms of a cold or flu or stop them from spreading. Colds and flus are viral infections and antibiotics are only effective against bacterial infections.
Here is a short summary of the postives and negatives of available treatments as you would find at your local chemist:
Antihistamines– common brands include Zyrtec and Clarityne.
Positives: shown to reduce overall symptoms on day 1 & 2 of a cold, but little help after that.
Negaitives: some people may experience side-effects, such as feeling drowsy.
Analgesics: commonly Panadol or an anti-inflammatory such as Nurofen.
Positives: may reduce fever, aches and pains a little.
Negaitives: no effect on how long the cold lasts or on runny nose/nasal stuffiness;
Ipratropium nasal spray such as Atrovent.
Positives: can reduce runny nose, but not blockage/stuffiness.
Negaitives: may cause dryness, irritation or mild bleeding from the nose.
Nasal saline rinses/sprays– a common example is Fess.
Positives: because it’s just salty water, side effects are unlikely, and it may help runny nose/blockage a little.
Negaitives: studies so far have not been large enough to confirm a benefit.
Steroid Nasal Sprays– common examples include Flixonase, Nasonex and Avamys.
There is no evidence that these assist in any way
Decongestant nasal sprays– common brands include Dimetapp, Otrivin & Sudafed sprays.
Positives: may make a small difference to stuffy/blocked nose.
Negaitives: may cause side effects such as dryness or irritation.
3 in 1 combination tablets with painkiller, decongestant & antihistamine.
For example Sudafed PE and allergy and pain relief.
Positives: may reduce overall symptoms and improve recovery time, in adults and older children.
Negaitives: potential for side effects, from any of the 3 components.
Positives: taking regular daily doses may reduce the duration of the common cold, but it won’t stop you getting colds in the first place, and won’t reduce severity of symptoms if you do catch a cold.
Negaitives: Consistent preventive dosing would be needed and the benefits are little if any.
Zinc tablets or capsules:
Positives: if taken in the first 1-2 days of a cold, these might reduce how long a cold lasts.
Negaitives: benefits are slight, and it should never be used in spray form as it can lead to permanent loss of one’s sense of smell
Colds and flu prevention
Good hygiene is the most important way to help prevent a cold or flu from being caught or spreading. Other ways to prevent a flu from being caught is an annual flu vaccination or the use of an anti-viral medicine but this only assists if taken within 48 hours of being exposed to the flu. In the end, it’s good hygiene practices that make the big difference. These include:
- washing your hands regularly and properly with soap and water,
- sneezing and coughing into tissues then throwing them away and immediately and washing your hands,
- cleaning surfaces such as your keyboard, telephone and door handles regularly to get rid of germs,
- not sharing cups, plates and cutlery.
You can watch this public information film from 1946, which advised the public to use a handkerchief to stop the spread of diseases - Coughs and sneezes spread diseases (1946)
The flu vaccine is available for anyone from six months of age. The best time to get the flu shot is early autumn to allow time for your immunity to be strengthened before the flu season commences. It is important to have the vaccine each year to continue to be protected because immunity decreases over time and the fact that flu strains also change over time.
People more at risk
Some people need to take extra care as they're more at risk of serious chest complications, such as pneumonia and bronchitis. People over 65 are more at risk of complications. People under 65, including children, are more at risk of complications if they have:
- serious heart or chest complaints, including asthma
- serious kidney disease or liver disease
- lowered immunity due to disease or medical treatment
- had a stroke