Six different "types' of Covid-19 have been discovered by scientists - each with their own “cluster of symptoms”.
Data gathered from King's College London's Covid-19 symptom study app gives fresh insight into who is most likely to be hospitalised.
Researchers say their work could have “important implications” for caring and monitoring people who are most vulnerable ahead of any second wave of the disease.They found that most people who require support breathing go to hospital around 13 days after they develop the first symptoms, the Liverpool Echo reports.
And knowing who is most likely to suffer a severe infection as early as day five could help save people’s lives.
A continuous cough, fever and loss of smell are recognised as the three main symptoms of the disease.
However, scientists said the data also showed a wide range of symptoms associated with Covid-19 such as headaches, muscle pains, fatigue, diarrhoea, confusion, loss of appetite and shortness of breath.
Study author Dr Claire Steves, from King's College London, said: "If you can predict who these people are at day five, you have time to give them support and early interventions such as monitoring blood oxygen and sugar levels, and ensuring they are properly hydrated - simple care that could be given at home, preventing hospitalisations and saving lives."
The six distinct types of Covid-19
Analysis was made based on the data gathered from around 1,600 users in the UK and US, between March and April, who had a confirmed Covid-19 diagnosis.
The results showed six specific clusters of symptoms, which according to the researchers, represented six distinct types of Covid-19.These clusters include:
Flu-like with no fever - Headache, loss of smell, muscle pains, cough, sore throat, chest pain, no fever
Flu-like with fever - Headache, loss of smell, cough, sore throat, hoarseness, fever, loss of appetite
Gastrointestinal - Headache, loss of smell, loss of appetite, diarrhoea, sore throat, chest pain, no cough
Severe level 1 fatigue - Headache, loss of smell, cough, fever, hoarseness, chest pain, fatigue
Severe level 2, confusion - Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain
Severe level 3, 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
The researchers said they recently identified skin rash as another key symptom of Covid-19 but it was not recognised as a symptom during the time when the data was gathered for their analysis - so it is currently unknown how skin rashes map on to these six clusters.
The team found that those who were older and frailer, overweight and had underlying conditions such as diabetes or lung disease were more likely to get the severe symptoms.
The researchers then developed a model to predict which cluster a patient falls into, and their risk of requiring hospitalisation and breathing support, based purely on age, sex, BMI and pre-existing conditions alone.
They believe prediction tools like these could provide an early warning sign as to who is most likely to need more intensive care, based on their early symptoms.
Sebastien Ourselin, professor of healthcare engineering at King's College London and senior author on the study, said: "Being able to gather big datasets through the app and apply machine learning to them is having a profound impact on our understanding of the extent and impact of Covid-19, and human health more widely."