More than 18 months after Covid-19 first emerged, scientists continue to be split on what the symptoms actually are.
Since the start of the pandemic, there have been more than 189 million confirmed cases, although the true number is likely to be far higher.
While the NHS recognises three main symptoms – high temperature, continuous cough and loss of smell and taste – health authorities across the world recognise a whole range.
Experts have caused for the NHS’s list of symptoms to be expanded to include sore throats, headaches, fatigue and diarrhoea.
Additionally experts from the Covid Symptom Study identify a total of 21 signs that someone has contracted the virus – including rashes on the skin, nausea, confusion and runny nose.
Calum Semple, a member of the government’s Scientific Advisory Group for Emergencies (Sage) group, said last month: “As older people are vaccinated, proportionally more younger people are having disease and they have a different group of symptoms.
“By extending the symptom list, we think we’ll pick up about a third more cases.
“But, more importantly, we’ll pick them up a day earlier and that offers greater opportunity to break transmission chains and stop further spread of the virus.”
To make things even more complicated, around a third of people show no symptoms at all.
Here we look at the main systems recognised in the UK, the US, as well as 21 used by the Zoe Covid study, which has tracked the number of cases throughout the crisis.
According to the NHS, there are three key symptoms.
Anyone who experiences any of these are required to get tested.
- a high temperature – this means you feel hot to touch on your chest or back (you do not need to measure your temperature)
- a new, continuous cough – this means coughing a lot for more than an hour, or 3 or more coughing episodes in 24 hours (if you usually have a cough, it may be worse than usual)
- a loss or change to your sense of smell or taste – this means you’ve noticed you cannot smell or taste anything, or things smell or taste different to normal
The World Health Organisation
The World Health Organisation has listed 13 known Covid-19 symptoms, with tiredness, sore throats, headaches and diarrhoea among them.
WHO scientists say fever, dry cough and tiredness are the most common symptoms, but then lists a range of other signs that someone could be infected.
Most common symptoms:
- dry cough
Less common symptoms:
- aches and pains
- sore throat
- loss of taste or smell
- a rash on skin, or discolouration of fingers or toes
- difficulty breathing or shortness of breath
- chest pain or pressure
- loss of speech or movement
The US Center for Disease Control and Prevention
Scientists across the Atlantic are in agreement over these three main signs that a person could have contracted Covid-19.
But the Center for Disease Control and Prevention (CDC) lists eight additional symptoms.
Additionally, it has identified five emergency warnings which could mean someone is in immediate danger from possible coronavirus.
The symptoms recognised by the CDC are:
- Fever or chills
- Shortness of breath or difficulty breathing
- Muscle or body aches
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
The Zoe Covid Symptom Study
The Zoe Covid Symptoms study was launched in March last year and has provided vital data used throughout the pandemic.
It was launched by health science firm Zoe with scientific analysis coming from King’s College London, and has over four million contributors around the world.
It has now identified 21 symptoms it believes are signs that a person could be infected.
Scientists say: “At first, it looked like the main symptoms of coronavirus infection were a high temperature and a persistent cough. But it soon became clear that there was more to COVID than cough and fever.”
The symptoms listed by the study are:
- High temperature
- Chills or shivers
- Persistent cough
- Loss or change in smell
- Loss or change in taste
- Unusual tiredness
- Sore throat
- Sudden confusion, especially in older people
- Skin rash
- Changes in the mouth or tongue
- Red and sore fingers or toes
- Shortness of breath
- Chest pains
- Muscle pains
- Hoarse voice
- Skipping meals
- Abdominal pains
- Runny nose
From Monday current restrictions to prevent the spread of the virus will be lifted in England.
This means masks will no longer be a legal requirement – although many companies say they will continue to enforce their use – and businesses will be allowed to operate at full capacity.
The government has admitted that it will cause cases to rocket, with Health Secretary Sajid Javid last week stating that he expects infections to reach 100,000 per day over the summer.