A study of more than a million people in England has revealed a range of symptoms that are linked with having COVID-19, according to a news release from Imperial College London.
Of these symptoms, seven were found to be best predictors of having COVID-19 among symptomatic individuals and could, therefore, improve case detection if included in testing criteria.
In addition to the symptoms used to identify who is eligible for a PCR test in England (fever, new continuous cough, loss or change to sense of smell or taste) –– 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-1 study showed that in addition to the symptoms above, chills, loss of appetite, headache and muscle aches were together most strongly linked with being infected. Having any of these either alone or in combination, was associated with higher risk of infection with the coronavirus and the more symptoms people showed the more likely they were to test positive.
People in England are currently encouraged to take a COVID-19 PCR test if they have at least one of the following symptoms: fever, new continuous cough, loss or change of sense of smell or taste. This is part of ‘Pillar 2 testing. Based on these findings, the researchers estimate that current Pillar 2 PCR 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.
These findings are from the ongoing REal-time Assessment of Community Transmission (REACT-1) program, led by Imperial College London.
The research also explored whether the emergence of the Alpha variant (B.1.1.7, first identified in Kent) was linked with a different profile of symptoms.
Comparing self-reported symptoms in participants infected by the ‘wild type’ (the first identified novel coronavirus) and those by the Alpha variant, showed that the symptoms that are predictive of Alpha variant infection were broadly similar to those predictive of the wild type infection. Nevertheless, in keeping with findings from the Office for National Statistics, new persistent cough and sore throat were more predictive of B.1.1.7 infection and loss or change of sense of smell was more predictive of the wild type.
The REACT-1 study is monitoring current coronavirus infections in the community by testing around 100,000 randomly selected people each month over a two-week period. The study recruits new people each month to help ensure the sample represents the wider population and offers a high-resolution snapshot of the situation across a particular time-period.
