• Richard Beschizza

NHS Test and Trace – What It Is, How It Works and What Employers Need To Know

Updated: Jul 22


To limit the spread of COVID-19, the government instituted several significant control measures, including two systems to identify those at risk of spreading the virus and alert those in danger of being infected.


The first is the Test and Trace system. In England, if you test positive for COVID-19, you will be contacted by the NHS Test and Trace service via text message, email or phone. When contacted by text or email, a link is sent to the NHS Test and Trace website to enter details of recent contacts. These details can also be shared over the phone. Contact tracers will also ask for the email addresses, home address and phone numbers of those who may have been exposed to coronavirus.


As well as the mandatory requirement to input information as part of the Test and Trace system, there is also the NHS COVID-19 app. The downloading and use of the app is entirely voluntary. It can also be uninstalled and deleted at will. It adds an additional level of protection for those who have come into contact with someone who has tested positive but perhaps the identity, time and location were not known and so that person was unintentionally missed off the information supplied to NHS Test and Trace.


However, only people who have been assessed as being involved in “high-risk” encounters will be notified. High-risk contacts are determined by data that is shared and fed into the app’s risk algorithm via Bluetooth technology.


Based on this, someone is likely to be at increased risk of contracting the virus if they’ve been within two metres of someone who has tested positive for more than 15 minutes. To calculate people’s risk scores, the app uses distance (via Bluetooth strength), time around a person and details about when their symptoms started. The NHS confirmed that the distance is measured between people in repeating and periodic five minute intervals.


The app also uses QR codes. Through an in-app camera function, it is able to scan QR codes at venues and log where you have been. Pubs, restaurants and other venues can create their own QR codes through a generator on the government website.


If you’ve been in close contact with someone who later tests positive for the virus, the NHS COVID-19 app can alert you as quickly as 15 minutes after that person shares their test result in the app. This includes people you do not know, such as someone you queued next to in a supermarket or sat next to on a bus.


From 28th September 2020, it was illegal for people not to self-isolate once they had been contacted by Test and Trace with £10,000 fines for breaking the rules. This will continue to be the case after 19th July.


However, according to the government website, users of the official NHS COVID-19 contact tracing app are anonymous and cannot be forced to self-isolate or identify themselves if they are not self-isolating. The app will advise a user to self-isolate if they have come into close contact with someone who has tested positive for coronavirus. Ultimately, use or non-use of the app carries no legal consequence should the user be ‘pinged’ but chooses not to self-isolate.


Issues with the app?


Bluetooth wasn’t built for contact tracing and there’s a chance that measurements may be incorrect, misleading or not truly representative of the risk. There are issues with how the system works when objects are in the way of the signals. This could mean people are asked to self-isolate due to close contact despite the fact that they were standing on the other side of a wall from someone with COVID-19. There is also no consideration of whether risk scores should be calculated differently when people are outside, where the risk of virus transmission is considered to be lower.


Clearly, this may prove problematic for many employers as restrictions relax after 19th July 2021.


Our next blog covers Track and Trace isolation alerts and the implications for employers.