Covid: People pinged by NHS app ‘four times more likely’ to have coronavirus, study finds

Medical workers take swabs at a drive-thru coronavirus testing station in southwest London. Credit: PA

People “pinged” by the NHS app in England and Wales are up to four times more likely to have Covid-19 than someone who is not alerted, a study has found.

Those told to isolate had a 3.7 to 4.0 relative risk of testing positive for the virus, according to a survey of more than 750,000 contributors to the Zoe Covid Symptom study, which uses data gathered from people's phones.

In Scotland, this number was even higher, with people pinged by the Protest Scotland app being 10 times more likely to have coronavirus.

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The Protect Scotland app was found to be more accurate at alerting positive-testing people in comparison to the English and Welsh equivalents.

Researchers found only 2.4% of fully vaccinated participants who were pinged, but felt physically normal, went on to test positive.

Those in the same group who had one or more Covid symptoms, however, were 11.7 times more likely to test positive.

A self-isolation message displayed on the NHS coronavirus contact tracing app. Credit: PA

The results come a day after government figures revealed the number of people told to self-isolate by the NHS Covid app has fallen by 20%.

It continued a trend which has seen alerts sent by the app fall for three consecutive weeks- a welcome sign for businesses which have been struggling to stay open due to staff shortages.The research also suggests that a significant number of people who are not infected are being asked to self isolate for the10-day-period in the UK after being alerted by tracing apps.

The government was forced to make changes to isolation rules last month, after businesses faced staff shortages due to the scale of those isolating. Ministers also performed a U-turn on the NHS app itself, tweaking it to so fewer contacts are told to self-isolate.

The survey found that younger people who were told to self-isolate by an app were more likely to be positive compared to older groups, with unvaccinated participants far more likely to contract Covid-19 compared to partially and fully vaccinated users.

Commenting on the findings, Professor Tim Spector, lead scientist of Zoe Covid Study app, said: “On Thursday the Health Secretary announced fully jabbed Covid contacts won’t need to self-isolate from August 16.

“While I welcome efforts to address the ‘pingdemic’, cases are still very high and our research shows that whatever your vaccination status, if you have one of possible 20-plus Covid symptoms recognised by Zoe – not just the classic three – you should be cautious, self isolate and get a test.

“Which makes it even more important for the government to expand the symptom list to help people understand all the symptoms of Covid-19."