Chills, loss of appetite, headache and muscle aches are among new symptoms identified with coronavirus infection, a new study in England has found.
Data collected from swab tests and questionnaires from June last year until January 2021 as part of Imperial College London’s REACT study on more than one million people found people with the symptoms listed above were more likely to test positive for Covid-19
This is in addition to the existing, more commonly recognised “classic” symptoms described by the NHS, which includes fever, a new persistent cough or loss of sense of smell and/or taste.
The study pointed out while these symptoms were associated with increased likelihood of infection, around 60% of infected people did not report any symptoms in the week leading up to their test.
There was also a variation in symptoms reported in relation to age.
Chills were linked with people testing positive across all ages, headaches were reported in people aged five to 17, appetite loss in 18-54 and 55+, and muscle aches in people aged 18-54.
Infected five to 17-year-olds were also less likely to report fever, persistent cough and appetite loss compared with adults.
What does this mean for testing?
Currently, people in England are encourage to take a coronavirus test if that have one of the “classic” symptoms as part of “Pillar 2 testing”.
Based on these findings, researchers estimate the existing, widely recognised symptoms for Pillar 2 testing would pick up around 50% of all symptomatic infections if everyone eligible were tested.
Experts believe if the new, additional symptoms were included in this list, around 75% of all symptomatic infections could be detected.
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.”
Are the new symptoms linked to the Kent variant?
It’s hard to say so far.
Researchers compared self-reported symptoms and swab test results collected from the REACT study from November to December, when Public Health England (PHE) estimated around 16% of infections were from the new variant, and compared that with data in January, when around 86% of infections were from the Kent variant.
While symptoms were broadly similar when comparing January to data collected in November and December, loss or change of smell was less predictive of having coronavirus.
Meanwhile, the proportion of people testing positive who had a persistent cough appeared to increase in January.
Dr Joshua Elliott, from Imperial College London’s School of Public Health, said: “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.
"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.”