Intended for healthcare professionals


Covid-19: UK pledges to reintroduce contact tracing to fight virus

BMJ 2020; 369 doi: (Published 21 April 2020) Cite this as: BMJ 2020;369:m1591

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  1. Gareth Iacobucci
  1. The BMJ

The government is to reintroduce contact tracing of people who have had symptoms of covid-19, England’s health secretary, Matt Hancock, said last week.

Hancock told MPs on the health select committee that the planned increase in testing capacity (the government has promised to conduct 100 000 tests a day by the end of April) would enable it to restart a policy that it stopped in March when the prevalence of the virus began to increase in the UK.

He said, “Community testing is part of the strategy, and we will be introducing it when we can. It wasn’t possible when we had small numbers of tests, but as we have expanding numbers of tests it will be possible.”

Hancock said that a central team would be set up to implement the strategy, which includes an app for people to trace and report their contacts themselves, alongside more traditional methods such as using health professionals to proactively contact and trace people.

“That [central team] brings together teams from NHSX, who are leading on the app, with a huge array of partners that are working within that, [and] from Public Health England, who are the experts on what we refer to as external contact tracing,” Hancock said.

Hancock said the app would “assist individuals to do contact tracing themselves by notifying people they have been in close contact with, and of course link that to testing so people can get the tests.”

If delivered, the ramping up of community testing would bring the UK back into line with countries such as South Korea, Singapore, Hong Kong, and Germany, which have all deployed extensive testing and contact tracing and so far have experienced relatively low fatality rates.

The World Health Organization has repeatedly emphasised the importance of contact tracing as a means for controlling the spread of the virus.

Approaches have varied. While the likes of South Korea have successfully used a tracking app through smartphones to trace contacts, there are some concerns about privacy with this approach. Other areas have adopted more low tech approaches. For example, San Francisco has asked public health professionals to conduct voluntary phone interviews with covid-19 patients, and they then call anyone that the patient has been in contact with and ask them to quarantine themselves for 14 days.1

There are also question marks over how effective digital technology is for contact tracing, with a rapid evidence review from an independent research institute published last week warning that there was currently no evidence to support the immediate national deployment of contact tracing apps in the NHS.2 It said, “The significant technical limitations, and deep social risks, of digital contact tracing outweigh the value offered to the crisis response.”

Anthony Costello, professor of global health and sustainable development at the UCL Institute for Global Health and a former WHO director, also appearing at the select committee hearing, said that the UK needed to adopt a traditional public health approach to contact tracing, and he suggested that retired clinicians could help with contacting people by phone. “Just asking people to self-isolate [via an app] is not going to achieve the quarantine you want to,” he cautioned.

“Now that we have a national lockdown, the aim must be to make sure we have all the logistics set up—digital apps, public health teams, maybe volunteers and primary care—to have an absolute plan to protect the community as soon as we lift the lockdown, and then focus on the people we really want to lock down, which is cases and contacts.”

Costello said he believed it was a mistake to abandon contact tracing in March across the whole of the UK, rather than just in areas such as London with a high prevalence of the virus.

He said, “As the WHO has said all along, you need to find cases, you need to test them if you can, you trace their contacts, you isolate them, do social distancing, and most importantly you do it all at speed. We have to face the reality of that—we were too slow. But we can make sure in the second wave that we are not too slow.”

But at the Downing Street press conference on 19 April England’s deputy chief medical officer, Jenny Harries, defended the government’s approach and questioned the link between low death rates and comprehensive contact tracing. She said, “We had a containment phase and it was very successful. We had strict quarantine regimes from high risk areas. We followed up individual cases and families.

“But once you end up with seeding and cases across the community, our focus has to be on managing the clinical conditions of those individuals.”

Costello took to Twitter to criticise Harries’s comments: “I cannot believe what I am hearing. Deputy CMO Jenny Harries still believes testing policy has been correct. And she doesn’t understand links between tests and Covid death rates. Is this CMO policy? If so, they should resign.”3

John Ashton, former regional director of public health for northwest England, who has also criticised the government’s decision to stop contact tracing, said he believed that cuts to public health had contributed to a lack of testing capacity. He said, “They started doing the right thing with quarantining the Wuhan returnees at Arrow Park, but then they only did that for a couple of weeks. It was quite bizarre that they threw their hands up and gave in.

“Reading between the lines, there seems to be a capacity issue for doing contact tracing, which is not surprising given that they’ve presided over such a significant reduction in the size of local and regional public health teams, with big cuts in budgets, big cuts in staff.

“If we had had the capacity for testing, there’s no reason why we shouldn’t have carried on doing what we were doing.”


  • Correction: On 29 April 2020 we corrected Anthony Costello’s job title.

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