Early symptoms resulting from a Covid-19 infection differ between men and women and among different age groups, research suggests.

The study, which looked at data from the Zoe Covid Symptom Study app, found that following Covid-19 infection, men were more likely to report shortness of breath, fatigue, chills and fever, while women were more likely to report loss of smell, chest pain and a persistent cough.

The researcher from King’s College London (KCL) 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.

The findings, published in the journal Lancet Digital Health, are based on modelling using artificial intelligence to predict early signs of Covid-19 infection.

Lead author, Claire Steves, Reader at KCL, said: “It’s important people know the earliest symptoms are wide-ranging and may look different for each member of a family or household.

“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.

However, they added, that the findings suggest the symptoms of the Delta variant and subsequent variants will also differ across population groups.

Dr Marc Modat, Senior Lecturer at KCL, said: “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.

“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.”