Since the early days of the pandemic, we’ve been aware that the main symptoms of COVID-19 are a persistent cough, a high temperature and a loss of smell or taste. But now, new research from King’s College London suggests that early symptoms could be far more wide-ranging and even seem to differ between men and women, and among different age groups.
The study, which analysed data taken from the Zoe COVID Symptom Study app from 20 April to 15 October 2020, found that following COVID-19 infection, men were more likely to report shortness of breath, fatigue, chills and shivers, while women were more likely to report loss of smell, chest pain and a persistent cough. The researchers also found those aged 60 and above were more likely to report diarrhoea symptoms, but loss of smell was less common among this age group.
In the paper, which was published in the journal Lancet Digital Health, the scientists compared the ability to predict early signs of COVID-19 infection using current NHS diagnostic criteria and a type of machine learning. The machine-learning model was able to incorporate some characteristics about the person affected, such as age, sex and health conditions, and showed that symptoms of early COVID-19 infection are different among various groups.
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“It’s important people know the earliest symptoms are wide-ranging and may look different for each member of a family or household,” said lead author Dr Claire Steves. “Testing guidance could be updated to enable cases to be picked up earlier, especially in the face of new variants which are highly transmissible. This could include using widely available lateral flow tests for people with any of these non-core symptoms.”
Overall, the research team examined 18 different symptoms associated with COVID-19, and the early signs included loss of smell, chest pain, persistent cough, abdominal pain, blisters on the feet, eye soreness and unusual muscle pain. The academics also found fever was not an early feature of the disease in any age group – despite being a known COVID-19 symptom.
They said their modelling study was used on the the original strain of the virus that first appeared in Wuhan, China, as well as the Alpha variant of coronavirus. They added that the findings suggest the symptoms of the Delta variant and subsequent variants will also differ across population groups.
“As part of our study, we have been able to identify that the profile of symptoms due to COVID-19 differs from one group to another,” said co-author Dr Marc Modat. This suggests that the criteria to encourage people to get tested should be personalised using individuals’ information such as age. Alternatively, a larger set of symptoms could be considered, so the different manifestations of the disease across different groups are taken into account.”