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Patients reporting loss of taste and smell ‘three times more likely’ to have Covid-19

Losing your sense of taste and smell may be one way to identify coronavirus (Covid-19) infection, early-stage research suggests.

Nearly 60% of patients, who subsequently tested positive for Covid-19, had reported losing their sense of smell and taste via the COVID Symptom Tracker app. This compared with just 18% who tested negative.

The app, developed by King’s College London, asks its 1.5 million users to log their symptoms (or lack thereof) daily. Of these users, 1,702 have been tested for the virus, and 579 reported they were confirmed positive.

Using this data, the research team developed a mathematical model to identify which combination of symptoms – from loss of taste and smell, to persistent cough – was the most accurate in predicting the infection.

These results were much stronger in predicting a positive Covid-19 diagnosis than self-reported fever, the researchers said.

Lead researcher Professor Tim Spector said: ‘When combined with other symptoms, people with loss of smell and taste appear to be three times more likely to have contracted Covid-19 according to our data, and should therefore self-isolate for seven days to reduce the spread of the disease.’

When applied to the 400,000 users who had not been tested but were reporting symptoms, the researchers found that up to 50,000 individuals are likely to have as yet unconfirmed Covid-19 infections.

The data, published online, has not been peer-reviewed.

Professor Spector also said: ‘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.’

This week, NHS England stated GPs are expected to carry out ‘proactive’ monitoring of some symptomatic patients.