Should you self-isolate after being ‘pinged’? Here are the signs to look out for

August 13, 2021

As the rules on self-isolation ease, it’s important that we all stay vigilant to help stop the spread of COVID-19 and protect those who are most at risk from the virus. 

Our recent ‘pingdemic’ survey shows that people who have been ‘pinged’ after coming into contact with a COVID case are more likely to test positive if they have any of the 20+ symptoms of COVID-19. 

Here’s what we found and what it means for you.

How are the rules on self-isolation changing?

The Government has announced that from Monday 16th August, people in England who have been fully vaccinated won’t be legally required to self-isolate if they’ve come into contact with someone who has tested positive. Instead, they’ll be asked to take a PCR test as soon as possible to check whether they’re infected, but will otherwise be able to go out and about as usual.

This move is designed to address the ‘pingdemic’, which has seen transport, food supplies and businesses disrupted by the number of people being asked to isolate, despite the fact that tens of thousands of people are still testing positive every day.

Although we know that vaccines provide good protection against becoming seriously ill with COVID-19, it’s still possible to catch and pass on the virus even if you’ve been double jabbed, leaving children, unvaccinated adults and those who are less well-protected by the vaccine at risk.

Results from our ‘pingdemic’ survey

Over one week in July, we asked contributors to the ZOE COVID Study app to confidentially tell us whether they’d been ‘pinged’ and told to self-isolate by anyof the UK contact tracing apps. More than 750,000 of you responded - thank you!

Next, we compared people who said they had been ‘pinged’ with those who had not, to see who went on to report a positive test.

We found that only 2.4% of fully vaccinated participants who were ‘pinged’ by either the NHS COVID-19 App or Protect Scotland App app and who felt physically welll went on to test positive for COVID. 

However, those who were pinged and also reported having one or more of the 20+ possible COVID-19 related symptoms, were nearly 12 times more likely to test positive. 

Figure 1: Positivity rate in people ‘pinged’ and ‘not pinged’ according to whether or not they had any symptoms of COVID-19


People who reported being ‘pinged’ by the NHS COVID-19 app in England and Wales were around four times more likely to have COVID-19 than someone who wasn’t. 

However, participants who got ‘pinged’ by the Protect Scotland app were around 10 times more likely to have COVID-19 than someone who wasn’t. 

This suggests that the Scottish app is doing a better job of alerting those who are likely to be positive after coming into contact with an infected person than in the other two nations. 

Figure 2: Relative risk of being positive of COVID-19 if pinged across NHS COVID-19 app and Protect Scotland app

We also discovered that younger people who were told to self-isolate after being ‘pinged’ were more likely to test positive compared to older age groups. And we found that unvaccinated participants were much more likely to test positive for COVID if they were ‘pinged’ compared with partially vaccinated and fully vaccinated users.

Figure 3: Positivity rate in ‘pinged’ and ‘not pinged’ people by vaccination status 

Should you self-isolate if you get ‘pinged’?

Overall, our findings tell us that a combination of symptom monitoring and contact tracing is more accurate when it comes to identifying who should self-isolate than ‘pinging’ alone, especially for people who have been vaccinated. 

Not only does this include the ‘classic three’ symptoms of fever, cough and loss of smell (anosmia), but also symptoms such as headaches, runny nose, sore throat or chest pain

Even though restrictions are easing, the only way out of the pandemic is to bring down the number of infections while protecting as many people as possible through vaccination. 

The message is clear: if you get ‘pinged’ and feel unwell, you should stay home and get tested to protect your loved ones and the community around you - even if you’ve been double vaccinated.

Professor Tim Spector, lead scientist at ZOE COVID Study and professor of genetic epidemiology at King’s College London, says,

“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+ COVID symptoms recognised by ZOE, you should be cautious, self isolate and get a test.”

Our findings also make it even more important that the Government expands the current list of COVID-19 symptoms beyond the ‘classic three’ of cough, fever and loss of smell, to help raise public awareness of the full range of symptoms of infection. 

Stay safe and keep logging.

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