Symptoms not widely linked to the virus – like confusion and abdominal pain – are found to be hallmarks of its most severe forms.
The different forms of the disease are believed to determine its severity among those infected – and whether they are likely to need respiratory support in hospital, Sky News reported.
Those behind the study, led by researchers from King's College London, say it will have major implications on treatment decisions during a potential second wave of coronavirus and could "save lives."
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Although a continuous cough, fever and loss of smell are usually highlighted as the three key symptoms of the illness, data gathered from around 1,600 users of the COVID Symptom Study app in the UK and U.S. shows that people can experience a wide range of different effects.
These can include headaches, muscle pains, fatigue, diarrhoea, confusion, loss of appetite, shortness of breath and more.
And researchers concluded that which of the six main cluster of symptoms each infected person suffered tended to indicate how quickly the disease would progress and how ill they were likely to get.
They presented the six distinct clusters – or "types" of COVID-19 – as follows:
1. 'Flu-like' with no fever – Headache, loss of smell, muscle pains, cough, sore throat, chest pain, no fever.
2. 'Flu-like' with fever – Headache, loss of smell, cough, sore throat, hoarseness, fever, loss of appetite.
3. Gastrointestinal – Headache, loss of smell, loss of appetite, diarrhoea, sore throat, chest pain, no cough.
5. Severe level two, confusion – Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain.
6. Severe level three, abdominal and respiratory – Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain, shortness of breath, diarrhoea, abdominal pain.