Intended for healthcare professionals


Covid-19: How does the NHS test and trace service work?

BMJ 2020; 369 doi: (Published 29 May 2020) Cite this as: BMJ 2020;369:m2174
  1. Elisabeth Mahase
  1. The BMJ

After numerous calls from public health experts since national contact tracing ended in March, the UK government has reimplemented the measure for covid-19 as of 28 May. The new NHS test and trace service is part of the government’s move to ease lockdown measures and reopen parts of the economy.

How will the new system work?

When people show symptoms of covid-19 they must isolate at home, along with the rest of the household, and order a test using the website or by calling 119. If people with symptoms then test positive they must complete the remainder of their seven day self-isolation, and their household must complete the 14 day isolation period. However, if the test is negative no one needs to isolate.

If people do test positive the NHS test and trace service will text, email, or call them with instructions on how to share details of people they have had close contact with. This will apply to contacts made and places visited two days before and seven days since the onset of symptoms.

The tracers will contact the people to tell them that they have been in close contact with someone who has tested positive, but they will not provide the name or details of this person. The alert will usually come by text, email, or phone call, but they may also come by post if needed. The contacts will be told to begin self-isolation for 14 days from their last contact with the person who tested positive. The contact’s household members do not need to self-isolate but should avoid contact with the person at home.

If a contact develops symptoms, the whole household must self-isolate for 14 days and the contact must order a test. However, this time if contacts test negative they must still isolate for the 14 day period, as the virus may not have become detectable yet, meaning that they could still go on to develop symptoms.

How do people get tested?

They can be tested using drive-through regional testing sites, mobile testing units, or test kits delivered to their home. The service aims to provide results within 48 hours of taking a test, along with advice on what to do next.

What are the symptoms?

The official symptoms listed are: high temperature; new, continuous cough (three or more coughing episodes in 24 hours); and loss or change in sense of smell or taste.

Who is defined as a contact?

This is someone who has been in the same household as the person who has tested positive or has been within two metres of the person for at least 15 minutes. For example, this may be people who have travelled in the same car.

Will people have to isolate if contacted?

Currently, people will just be asked to follow the advice, but more powers could be brought in to enforce the rules if they are not followed.

Dido Harding, who is leading the NHS test and trace service, said in a press briefing on 27 May, “I really do have faith in the British public. Everyone wants to get out of national lockdown, and they will see this as a way that they can play their part and make that possible. That’s the spirit in which we should go into this. It’s worth noting, however, that the secretary of state for health does have the power to mandate this if needed. But we will start by appealing to everyone that it is our civic duty to do this, and do this well.”

What about those who have already had covid-19?

They will still be asked to isolate if they have symptoms or are a contact, as not enough is yet known about immunity to covid-19.

What about those who may lose pay if they cannot work?

Harding, who was formerly chief executive of the TalkTalk Group, has said that anyone who is told to isolate by NHS test and trace will be eligible for statutory sick pay. Those who are self-employed will be able to claim a grant through the self-employment income support scheme. She added, “Last week we also announced £300m [€333m; $370m] to be allocated out to all higher tier local authorities to develop their own local test and trace plans, to make sure at a local level we are able to support people to isolate for two weeks.”

Are the tests accurate enough to allow people to stop isolating?

Concerns have been raised over how often the swab tests produce false negative results, which could release people from self-isolation under even though they are infected.

Margaret McCartney, GP and former BMJ columnist, said, “The experts I’ve spoken to think the false negative rate is probably now less than 30% but don’t know how much by. The point is we don’t know, but it could be that a third of people who have symptoms of covid test negative . . .

“It’s absurd for the government to roll out a hugely expensive programme without knowing a rough false negative rate and making sure it’s used rationally—ie, in context with symptoms. Worryingly, there is a possibly big chance that believing unreliable negative results will result in more covid-19 being spread.”

Who is doing the tracing?

Private call centre operators have been given the contracts to run the system,1 and around 25 000 people have been recruited to carry out the contact tracing. However, some issues with the training have been reported. A number of the tracers told the Guardian newspaper that there had been some technical difficulties and that, since they had done only a few hours’ training, they feel unprepared.2

The Sheffield contact tracing team, a group of retired doctors and public health experts who piloted local contact tracing after becoming frustrated with the lack of initiative from the government, also warned that a call centre based national system might be “too centralised and too remote.” The team warned that the “minimum wage based proposal is fraught with difficulties” and said that a more local approach would be better.3

What happened with the app?

Matt Hancock, England’s health secretary, previously said that the app, which started trials on the Isle of Wight in early May, would be available by mid-May, but this did not happen. Since then the launch date has been repeatedly pushed back, and now it seems that dates have been completely dropped.4 Harding has said that it is “coming soon.”

How will personal information be protected?

The government has said5 that all information provided to the service will be held in “strict confidence and will only be kept and used in line with the Data Protection Act 2018.” However, it has been reported that the personal data about people with coronavirus will be kept for 20 years, while contacts will have their information, except their date of birth, stored for five years.6

What about phishing scams?

A number of phishing scams have already been reported regarding covid-19, with people receiving text messages appearing to be from an official source telling them that they have been in contact with someone who has the virus and that they therefore need to provide personal details. The Action Fraud reporting centre says that covid-19 related scams have already led to £2m being stolen.

To counter this, the government has set out exactly what official contact tracers will and won’t ask. This includes that tracers will call from 0300 013 5000; send any text messages from “NHS”; ask people to sign into the NHS test and trace website; ask for full name, date of birth, and postcode; and ask about symptoms. However, they will never ask people to: dial a premium rate number (such as numbers starting 09 or 087); make any form of payment or purchase; provide any bank details; provide any social media identities or login details; or access any non-government or NHS website.

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