St Thomas' researchers launch COVID-19 symptom-tracking app

Researchers have developed a symptom tracking app, and are asking members of the public to log their symptoms – or lack of them – every day, to help scientists learn more about the virus.

Of the 1.5 million app users they studied last week, 26 per cent are reporting illness.

A total of 1,702 people on the app have been tested, and 579 have Covid-19.

KCL scientists worked with analysts at nutritional science start-up ZOE to assess symptoms and predict signs of the illness.

These include a persistent cough, fatigue, diarrhoea, abdominal pain and low appetite.

But loss of taste and smell was the most accurate indicator: 59 per cent of those who tested positive for coronavirus reported this symptom, compared to just 18 per cent of negative testers.

It was more strongly linked to a positive result than a self-reported fever.

With more than 400,000 people reporting possible signs of Covid-19 via the app, these findings suggests 50,000 could have the virus undiagnosed.

KCL lead researcher Professor Tim Spector said people who can't smell or taste should self-isolate to prevent further spread of the disease.

He said: "This urgent research is only possible thanks to the now 1.8 million citizen scientists logging their symptoms every day.

"This also gives us an evolving map of the UK of where symptoms are occurring two to three weeks before a strain on the NHS, which is why it's vital to continue logging your health and symptoms, even when you feel completely healthy, and encourage others to use the app."

You can download the app and join the research here: http://covid.joinzoe.com/

ZOE – a spin-out from KCL – is based at the Health Foundry med-tech co-working space at Canterbury House in Royal Street, just across from St Thomas'.

Around 5,000 twins and their families across the UK have been recruited from the TwinsUK cohort study – co-ordinated at St Thomas' – to trial the app, which tracks in real time how the disease progresses.

Twins using the app will record information about their health on a daily basis, including temperature, tiredness and symptoms such as coughing, breathing problems or headaches.

The aim is to send participants COVID-19 home testing kits to better understand which symptoms truly correspond to coronavirus infection.

The app is also available to the general public without the home testing component of the study.

The TwinsUK COVID-19 research study is funded by King's College London, ZOE Global Ltd, the CDRF charity, and the National Institute of Health Research Guy's and St Thomas' Biomedical Research Centre.