According to a study conducted by researchers from King’s College London, there are six distinct kinds of coronaviruses, each distinguished by a particular cluster of symptoms.

The team noted in their study that these types differed in the severity of the disease and the need for respiratory support during hospitalisation.

The findings have major implications for clinical management of Covid-19 and could help doctors predict who is most at risk and likely to need hospital care in the second wave of coronavirus infections.

The data gathered for the study revealed that people can experience a wide range of different symptoms including headaches, muscle pains, fatigue, diarrhoea and confusion, among others. These are not the typical symptoms of the coronavirus which include cough, fever, and loss of smell (anosmia).

The progression and outcomes also vary significantly between people, ranging from mild flu-like symptoms or a simple rash to a severe or fatal disease, the study said.

To find out whether particular symptoms tend to appear together and how this related to the progression of the disease, the research team used a machine-learning algorithm to analyse data.

It was gathered from a subset of around 1,600 users in the UK and the US with confirmed Covid-19 who had regularly logged their symptoms using the app in March and April.

The analysis revealed six specific groupings of symptoms emerging at characteristic time points in the progression of the illness, representing six distinct ‘types’ of Covid-19.

The algorithm was then tested by running it on a second independent dataset of 1,000 users in the UK, the US, and Sweden, who had logged their symptoms during May.

Six key clusters

The six 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 one, fatigue: Headache, loss of smell, cough, fever, hoarseness, chest pain, fatigue.

Severe level two, confusion: Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain.

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.

Early intervention

Commenting on the study, Dr Claire Steves from King’s College London said in a media statement: “These findings have important implications for care and monitoring of people who are most vulnerable to severe Covid-19.”

He added: “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 hospitalizations and saving lives.”