CORONAVIRUS affects everyone differently - killing some while leaving others blissfully unaware that they have been infected at all.
For the majority of people who get the deadly bug, their symptoms will be classified as “mild” and they will be able to stay at home and recover.
⚠️ Read our coronavirus live blog for the latest news & updates
However, for an estimated one in five people with Covid-19, they will develop more severe symptoms and hospital care will be vital.
Medics have been classifying the range of levels of coronavirus into five different categories to help people better understand the nature of their illness.
It comes as the number of cases of coronavirus yesterday rose to 55,242 - with the death toll standing at 6,159.
This terms generally used to classify the illness are:
Each of these 'levels' of illness is considerably less common than the previous one - so severe is less common than moderate, which is less common than mild and so on.
But it is not an exact science and you may well not fit into a single specific classification.
For example, you may move from mild to moderate symptoms, then back to mild and you may have symptoms from more than one group.
In each category, most people will not progress to the next.
However, you are more likely to progress if you have an underlying health condition or if you are over 60.
Here, we take you through each of the five categories and where you might fit in...
1. Asymptomatic Covid-19
For as many as 25 per cent of individuals infected with Covid-19, the deadly illness can be practically invisible as they develop none of the typical symptoms.
And if you don't display any signs - known as being 'asymptomatic' - then the risk of infecting others increases as people do not know to self-isolate.
The US Centers for Disease and Control (CDC) said: "Some spread might be possible before people show symptoms; there have been reports of this occurring with this new coronavirus, but this is not thought to be the main way the virus spreads."
Those who are asymptomatic are most likely to be healthy, younger and even children.
There are reports of loss of sense of smell in asymptomatic people but technically even that isn't a symptom.
2. Mild Covid-19
According to Patient Info, people with mild coronavirus have flu-like symptoms - these may include a dry cough and mild fever.
Your temperature may not reach 37.8C, and there may sometimes be little or even no cough.
Patients might notice a feeling of being a bit more breathless than normal on exercise, but they are not out of breath on normal household activity.
You may also lose your sense of taste and smell and experience tiredness, fatigue and muscle aches.
CORONAVIRUS CRISIS - STAY IN THE KNOW
Don't miss the latest news and figures - and essential advice for you and your family.
To receive The Sun's Coronavirus newsletter in your inbox every tea time, sign up here.
To follow us on Facebook, simply 'Like' our Coronavirus page.
Get Britain's best-selling newspaper delivered to your smartphone or tablet each day - find out more.
Around 81 per cent of symptomatic Covid-19 cases are mild and remain mild in severity.
The illness typically seems to last about seven to ten days.
However, patients with mild disease can deteriorate, sometimes quickly, and this is more likely in at-risk groups.
3. Moderate Covid-19
For those with more moderate symptoms, the illness seems to last about seven to 14 days.
These patients will have a more troublesome cough due to inflammation lower down in the lungs and your temperature is more likely to reach or exceed 37.8C.
They may also be a little sore from the coughing but will not be in pain.
Dr Mary Lowth, GP and medical writer, said: "The lungs consist of large airways (bronchi), smaller airways (bronchioles) and the tiny air sacs on the end (alveoli) where oxygen is extracted from the air.
"They contain a fluid called surfactant which keeps the lungs stretchy and compliant and helps keep the air sacs open.
"Patients with moderate Covid-19 may have inflammation moving down into the bronchioles.
"They are more breathless and tend to have an increased heart rate, particularly if they are moving around."
People with moderate Covid-19 may also find their sleep is disturbed by their cough and they may get diarrhoea or a headache.
4. Severe Covid-19
Severe Covid-19 means that you have pneumonia, which is inflammation caused by infection of the lungs themselves, right down into the tiny air sacs.
You are much more likely to develop this severity of coronavirus if you are older or have an underlying health condition.
It is not impossible in the healthy but it is much less common.
Patients with severe disease are very breathless - and may be unable to breathe at a comfortable rate on slight moving around or even at rest.
They will also breathe faster than usual, even when sitting still and cannot finish a sentence without extra breaths. They may even avoid speaking.
Their chest, tummy or back will hurt when they breathe and they will have a high temperature.
Dr Lowth adds: "Their oxygen levels may have fallen so the urge to breathe faster is strong.
"Doctors will measure breathing rates when assessing this condition.
"Normal adults breathe at about 12-18 breaths per minute when they are not thinking about it. In pneumonia the rate rises, sometimes markedly."
5. Critical Covid-19
Critical coronavirus patients are very unwell and will need help inflating their lungs with a ventilator.
They usually develop a condition called acute respiratory distress syndrome (ARDS).
According to the NHS, this is a life-threatening condition where the lungs can't provide the body's vital organs with enough oxygen.
This occurs when the lungs become severely inflamed due to an infection or injury and the inflammation causes fluid from nearby blood vessels to leak into the tiny air sacs in your lungs, making breathing increasingly difficult.
Give now to The Sun's NHS appeal
BRITAIN’s four million NHS staff are on the frontline in the battle against coronavirus.
But while they are helping save lives, who is there to help them?
The Sun has launched an appeal to raise £1MILLION for NHS workers.
The Who Cares Wins Appeal aims to get vital support to staff in their hour of need.
We have teamed up with NHS Charities Together in their urgent Covid-19 Appeal to ensure the money gets to exactly who needs it.
The Sun is donating £50,000 and we would like YOU to help us raise a million pounds, to help THEM.
No matter how little you can spare, please donate today here
Symptoms of ARDS can include severe shortness of breath, rapid, shallow breathing, tiredness, drowsiness or confusion and feeling faint.
About 15 per cent of coronavirus cases develop this, according to the Chinese Center for Disease Control and Prevention.
The most critical of all of these patients develop sepsis, and other bodily organs stop working - a very dangerous situation for the body.
The risk of getting critical coronavirus rises with age and if you have an underlying health condition - but this doesn't mean healthy younger people also aren't at risk.
More on coronavirus
People can survive critical Covid-19 with help from intensive care, but even that is not always enough, as we are seeing worldwide.
You should call 999 immediately if you think you or someone you know have the symptoms of severe or critical Covid-19.
Make sure you tell the call handler that you think you have coronavirus or coronavirus symptoms.