Six types of COVID-19 identified: Know the symptoms associated with each type

Understanding the types of COVID-19 can help doctors predict which patients may need hospitalisation and breathing support much earlier.

Overweight and those who have pre-existing conditions such as diabetes or lung disease more likely to develop severe COVID-19 symptoms.

Researchers are coming up with new findings related to the novel coronavirus almost every day. It is clear that the virus enters the body via nose, eyes, or mouth, and it can be transmitted through droplets expelled when an infected person coughs, sneezes, or speaks. Now, researchers have identified six distinct types of COVID-19, each distinguished by a particular cluster of symptoms. In addition, these types also differed in the severity of the disease and the need for respiratory support during hospitalisation.

The researchers from the King's College London in the UK were able to identify the different types of COVID-19 by analyzing data collected from a widely-used COVID-19 symptom-tracking app.

"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 a second wave of coronavirus infections," the researchers noted in a statement published in the college's official website.

Lesser-known symptoms of COVID-19

Cough, fever, and loss of smell (anosmia) are considered as the key symptoms of COVID-19. But data gathered from the COVID Symptom Study app users shows that coronavirus patients can experience a wide range of different symptoms including headaches, muscle pains, fatigue, diarrhea, confusion, loss of appetite, shortness of breath and more. The data also reveals that progression and outcomes also vary significantly between patients. While some develop only mild flu-like symptoms or a simple rash, others suffer severe or fatal disease, according to the data.

To find out whether any particular symptoms are related to the progression of the disease, the research team used a machine learning algorithm to analyse data obtained from 1,600 users in the UK and US with confirmed COVID-19 who had regularly logged their symptoms using the app in March and April.

The researcher found six specific groupings of symptoms emerging at characteristic time points in the progression of the illness, representing six distinct 'types' of COVID-19. They also tested the algorithm on a second independent dataset of 1,000 users in the UK, US and Sweden, who had logged their symptoms during May.

6 clusters of COVID-19 symptoms

The study, released online but not peer-reviewed by independent scientists, described the six symptom clusters as:

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, diarrhea, sore throat, chest pain, no cough.
4. Severe level one, fatigue: Headache, loss of smell, cough, fever, hoarseness, chest pain, fatigue.
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, diarrhea, abdominal pain.

Patients with cluster 4, 5 and 6 types were found to be more likely to be admitted to hospitals and require breathing support in the form of ventilation or additional oxygen. Only 1.5% of people with cluster 1, 4.4% of people with cluster 2 and 3.3% of people with cluster 3 COVID-19 required breathing support as compared to 8.6%, 9.9% and 19.8% for clusters 4,5 and 6 respectively. Nearly half of the patients in cluster 6 ended up in hospital, compared with just 16% of those in cluster 1.

"These findings have important implications for care and monitoring of people who are most vulnerable to severe COVID-19," said Dr Claire Steves from King's College London.

"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," the researcher added.