Boris Johnson’s insistence that the UK will be able to roll out a “world-beating” coronavirus test, track and trace regime by 1 June has inevitably drawn comparisons with countries around the world that have already set up effective Covid-19 tracing programmes.
It has also raised questions about timing, as some experts insist a system would have been more useful at the beginning of the pandemic.
Contact tracing is one of the most basic planks of public health responses to a pandemic like the coronavirus. It means literally tracking down anyone that somebody with an infection may have had contact with in the days before they became ill. It was – and always will be – central to the fight against Ebola, for instance. In west Africa in 2014-15, there were large teams of people who would trace relatives and knock on the doors of neighbours and friends to find anyone who might have become infected by touching the sick person.
Most people who get Covid-19 will be infected by their friends, neighbours, family or work colleagues, so they will be first on the list. It is not likely anyone will get infected by someone they do not know, passing on the street.
It is still assumed there has to be reasonable exposure – originally experts said people would need to be together for 15 minutes, less than 2 metres apart. So a contact tracer will want to know who the person testing positive met and talked to over the two or three days before they developed symptoms and went into isolation.
South Korea has large teams of contact tracers and notably chased down all the contacts of a religious group, many of whose members fell ill. That outbreak was efficiently stamped out by contact tracing and quarantine.
Singapore and Hong Kong have also espoused testing and contact tracing and so has Germany. All those countries have had relatively low death rates so far. The World Health Organization says it should be the “backbone of the response” in every country.
Sarah Boseley Health editor
Since mid-March, the World Health Organization has urged countries to scale up the testing, isolation and contact tracing of Covid-19 patients in order to combat the pandemic. Countries that initiated test and trace regimes early – including Germany, South Korea, Hong Kong, New Zealand and Canada – have fared better than those that did not.
One of the most striking success stories has been South Korea, which started its regime several weeks before the WHO’s “test, test, test” appeal in March. The country was quickly able to test an average of 12,000 people a day – and sometimes as many as 20,000 – at hundreds of drive-through and walk-in testing centres, free of charge. Results were sent to people’s phones within 24 hours.
As some commentators have remarked, South Korea’s regime was built on the base of well-funded public services and an effective infrastructure, including widespread digital surveillance.
Germany has emerged as another effective model. The country has carried out a rigorous test and trace programme since the first case of the virus was registered in late January. The Robert Koch Institute (RKI), the government’s main advisory body on public health, has repeatedly referred to the programme as a basic epidemiological tool necessary for the virus’s containment.
The system was hampered by a lack of staff at the overstretched local health authority offices responsible for enacting it, but over the weeks hundreds of containment scouts – often medical students – have been trained by the RKI to help out. About 500 of them are operational around the country.
Typically when a new infection is registered, a hygiene inspector at the health office asks the infected person the following questions: how long have they had symptoms, where might they have been infected, have they been at work, with whom have they been in touch and in what way, and are school or nursery age children in the household?
Contacts are questioned and put into different categories by a team of at least a dozen staff, including doctors and containment scouts, and then quarantined. Contacts are not automatically tested, in order to avoid a negative result that could trigger a false sense of security,
Canada, with its experience of being the only country outside Asia to have deaths in the Sars outbreak of 2003, was also quick to conduct tests and contact tracing. As of mid-May more than a million people had been tested for Covid-19, using a centralised network of laboratories.
Jimmy Whitworth, a professor of international public health at the London School of Hygiene and Tropical Medicine, is among those to express scepticism about the framing of the UK’s test and trace programme as “world-beating”.
“World-beating, at the start of an outbreak, would been to have had a system large enough to be able to cope with number of tests needed,” Whitworth said. “Not just sending them out but doing them and reporting back so that you can take action and having the contact tracing to be able to identify people who might be incubating the disease.
“If we come back to the situation now, there remains a question about [having a test and trace programme] large enough. The ONS [Office for National Statistics] data just released for England identifies 9,000 new cases a day.
“Successful programmes like South Korea and Australia are doing 50 to 60 [contact] tests for every case. So we have got to have a system that can cope with that number of tests.”
Whitworth also said countries that have been successful have deployed large amounts of human resources quickly and effectively, such as Germany’s “contact scouts” and South Korea’s rapid-reporting system.
“The human element is central. If you have a web-based system or an app those are things that add value but they don’t replace the human capital. They are good when tracing becomes difficult like if a confirmed case has got on a bus. That’s where an app can identify potential contacts.
“The other thing very important is to make it convenient. And at the moment the systems here [in the UK] seem to be set up for convenience of the system and operators, not the users.”