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20 January 2022

One in four people who had COVID-19 symptom do not test

Analysis by King’s researchers of the ZOE COVID Study app finds one in four people who had a symptom associated with COVID-19 did not undergo testing.


Research found older age groups were most likely to not recognise they had a key symptom that qualified for a COVID-19 test. These symptoms are fever, cough, or change or loss of smell/taste. The findings suggest there is still work to be done to raise public awareness of symptoms and access to testing.

The team, led by Mark Graham from the School of Biomedical Engineering & Imaging Sciences, analysed health reports submitted by more than 4 million contributors to the ZOE COVID Study app, along with the results of COVID tests. They targeted a survey to users to reported having one or more test-qualifying symptoms for the first time between 14 November and 8 December 2020 and who did not take a test.

In this survey, only two in five people could identify the classic ‘triad’ of symptoms – fever, cough and change or loss of smell/taste – which triggers a COVID-19 test. The lowest recognition of the tria was among the oldest age groups.

Two in five survey respondents recalled having at least one test-qualifying symptoms in the past month. Of those who recalled their symptoms, just half recognised these symptoms qualified them for a COVID-19 test.

In a separate follow-up survey from a sub-cohort of the University of Maryland Global COVID-19 Trends and Impact Survey from 21 December 2020 to 21 February 2021, researchers attempted to understand the reasons preventing people from getting a test. Among those who wanted testing, “I don’t know where to go” was the most frequently selected option (32.4%). Other reasons were: “I am unable to travel to a testing location” (29.1%), “I tried to get a test but was not able to get one” (25.6%), “I am worried about bad things happening to me or my family (including discrimination, government policies, and social stigma)” (18.4%), “I can't afford the cost of the test” (17.9%), and “I don't have time to get tested”(13.3%).

Our study allowed us to survey app users who had reported symptoms that would qualify them for a PCR test but had not reported getting a test. The results of the survey gives valuable insight into why people do not get tested. We were surprised by just how many respondents could not identify that cough, loss of smell, and fever were the three test-qualifying symptoms.

Dr Mark Graham, from the School of Biomedical Engineering & Imaging Sciences

He added: "This shows that efforts need to be made to educate the public about symptoms for COVID-19. Any expansion of the list of test-qualifying symptoms will need to be accompanied by clear and memorable messaging.”