Cold, flu, or COVID-19?
As COVID-19 has many similar symptoms to a cold or the flu, it can be hard to tell the difference and know if you need to self-isolate. The best way to be sure is to familiarise yourself with the symptoms of each condition so that you know what to do to keep yourself and the people around you safe. If you are worried that you have coronavirus and can't tell if it's another condition, you should use the NHS track and trace application or contact NHS 111. You can also order a coronavirus PCR test that will tell you if you have coronavirus right now.
How can I tell the difference between a cold, flu and coronavirus?
While these illnesses have similar symptoms, they usually do not share all of them. And, it's unlikely you will get these illnesses at the same time or all of their symptoms. Below you can find a table detailing their symptoms and the differences between them.
As you can see, both COVID-19 and flu can have a range of varying symptoms which can be severe and, in some cases, 'asymptomatic' (showing no symptoms). The most common symptoms that the flu and COVID-19 can share are:
- Shortness of breath or difficulty breathing
- Fatigue (tiredness)
- Sore throat
- Runny or stuffy nose
- Muscle pain or body aches
The primary way to spot the difference between the two is that COVID-19 may cause some people to lose their sense of taste and smell. Colds differ to both as they tend to result in a less severe illness.
COVID-19 - The most common symptoms of coronavirus are a fever, a new persistent cough (usually dry), and a loss of sense of taste and/or smell. You may also sometimes have symptoms including fatigue, aches and pains, sore throat, headaches and shortness of breath. Diarrhoea and a runny or stuffy nose are rare.
Flu - Flu most commonly consists of fever, fatigue, a dry cough, aches and pains and headaches. Patients will sometimes experience a runny or stuffy nose or a sore throat. There is usually no sneezing with flu, but the shortness of breath can develop. The symptoms of flu usually set in quite quickly.
Cold - The most common symptoms of a cold are sneezing, aches and pains, a runny nose and sore throat. There is sometimes fatigue, but it is rare to experience a fever or headaches. The symptoms of a cold tend to set in quite gradually.
How long does it take for symptoms to appear after infection?
With both coronavirus and the flu, it can take 1 or more days before an infected person starts experiencing symptoms, but this can take longer with coronavirus. With a cold, you may not experience any symptoms until after 3 days of becoming infected.
Coronavirus - Symptoms typically appear 5 days after becoming infected, but symptoms can occur any time between 2-14 afterwards.
Flu - Symptoms can take 1-4 days to appear following an infection.
Cold - It can take up to 3 days to notice the symptoms of a cold following an infection.
How long am I infectious for?
For both COVID-19 and flu, it's possible to spread the virus for at least 1 day before experiencing any symptoms. With a cold, you are infectious a few days before showing any symptoms, and you can remain infectious until you no longer have symptoms.
Flu - Most people with flu are contagious for approximately one day before they start showing symptoms and will be most contagious during the first 3-4 days of the illness, but they can still be contagious for up to 7 days.
COVID-19 - How long you're contagious for after catching COVID-19 is still being researched. However, it's currently thought that most people are infectious 2 days before showing any symptoms and can remain contagious for the first 10 days of the illness.
Cold - If you have a cold, you tend to be infectious until all of your symptoms have gone (which can take 2-3 weeks). Symptoms are usually worse during the first 2 to 3 days, and this is when you're most likely to spread the virus.
How do these illnesses spread?
All of these conditions are viruses which tend to spread through the air and close personal contact. They can also be spread through droplets from coughing or sneezing by an infected person or from a contaminated surface.
And, while these illnesses do spread in similar ways, COVID-19 can be more contagious among different populations and age groups. There have also been more COVID-19 'super spreader' events recently, leading to a much higher rate of transmission.
Can I get a vaccine for the cold, flu or coronavirus?
Flu - You can currently only get a vaccine for the flu. There are multiple flu vaccines produced annually, and it's recommended to get one if you are in a vulnerable group.
Cold - There is no cure or vaccine for the common cold as they would be complicated to make. This is because there are over 200 varieties of viruses that can cause colds and it wouldn't be feasible to vaccinate against all of these. Colds also tend to be less dangerous than the flu or COVID-19 making developing a vaccine less of a priority.
COVID-19 - There is currently no vaccine available for COVID-19, but multiple vaccines are being tested with the hopes of one being widely available in the near future.
Dr Babak Ashrafi Clinical Lead for Service Expansion
Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.Meet our doctors
Last reviewed: 13 Nov 2020