Credit Imperial College London
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The course of illness with COVID-19 is highly variable, ranging from asymptomatic carriage to mild or moderate illness to life threatening. While some symptoms are common (e.g. fever, cough, fatigue, etc.) they are not universal, and other - less obvious - symptoms, sometimes occur.
We've been following various aspects of Imperial College London's multi-faceted Real-time Assessment of Community Transmission (REACT) Study since last summer, including:
UK: Results From REACT (Real-Time Assessment Of Community Transmission of COVID-19) Study - Jan 2021
Yesterday, Imperial College London published a press release on the latest findings - presented in a Preprint study (see link below) - which describes a growing panoply of symptoms from COVID-19, including some subtle differences noted with the Kent Variant (B.1.1.7).
COVID-19 linked with wider set of symptoms than previously thought – REACT study
by Justine Alford 10 February 2021
A study of over a million people in England has revealed additional symptoms that are linked with having the coronavirus.
In addition to the ‘classic’ symptoms – loss of sense of smell and taste, fever and new persistent cough – a wide range of other symptoms were associated with COVID-19. However, around 60% of infected people did not report any symptoms in the week leading up to their test.
Swab tests and questionnaires collected between June 2020 and January 2021 as part of the Imperial College London-led REACT study showed that among these other symptoms, chills, loss of appetite, headache and muscle aches were together most strongly linked with being infected, alongside the four classic symptoms. Having any of these other symptoms or the classic ones, either alone or in combination, was associated with infection with the coronavirus and the more symptoms people showed the more likely they were to test positive.
The study also found that there was variation in symptoms with age. While chills were linked with testing positive across all ages, headaches were reported in young people aged 5-17, appetite loss in 18-54 and 55+, and muscle aches in people aged 18-54. Infected 5-17-year-olds were also less likely to report fever, persistent cough and appetite loss compared with adults.
Implications for COVID-19 testing
People in England are currently encouraged to take a COVID-19 test if they have at least one of the four classic symptoms: loss of sense of taste, loss of sense of smell, fever, new persistent cough. This is called ‘Pillar 2 testing’. Based on these new findings, the researchers estimate that current Pillar 2 testing would pick up around half of all symptomatic infections if everyone eligible were tested. But if the additional symptoms were included, this could be improved to three-quarters of symptomatic infections.
Professor Paul Elliott, director of the REACT programme at Imperial, said: “These new findings suggest many people with COVID-19 won't be getting tested – and therefore won't be self-isolating – because their symptoms don’t match those used in current public health guidance to help identify infected people.
"We understand that there is a need for clear testing criteria, and that including lots of symptoms which are commonly found in other illnesses like seasonal flu could risk people self-isolating unnecessarily. I hope that our findings on the most informative symptoms mean that the testing programme can take advantage of the most up-to-date evidence, helping to identify more infected people.”
These findings from the ongoing REal-time Assessment of Community Transmission (REACT-1) programme, led by Imperial and carried out in partnership with Ipsos MORI, are available in a pre-print report and will be submitted for peer-review. REACT is funded by the Department of Health and Social Care.
New coronavirus variant symptoms
The research also explored whether the emergence of the UK’s new coronavirus variant, first identified in Kent, was linked with a different profile of symptoms.
The researchers compared self-reported symptoms and swab test results collected for the REACT study in November – December, when PHE estimated the variant made up around 16% of infections, with similar data collected in January, when an estimated 86% of infections were from the variant.
While symptoms were broadly similar, in January compared to November – December, loss or change to sense of smell was less predictive of having COVID-19, while the proportion of people testing positive with a new persistent cough appeared to be increased, in keeping with findings from ONS.
“As the epidemic progresses and new variants emerge, it’s essential that we keep monitoring how the virus affects people so that testing programmes meet changing needs," said Dr Joshua Elliott, from Imperial College London’s School of Public Health. "We hope that our data will help inform testing guidance and the development of systems which could help better identify people who should take a COVID-19 test based on their symptoms.”
Authors: Elliott, J Whitaker, M Bodinier, B Riley, S Ward, H Cooke, G Darzi, A
Chadeau-Hyam, M Elliott, P Item
