14/02/2020 12:33 GMT | Updated 03/03/2020 12:25 GMT

The Coronavirus Chasers: These People Are Racing To Stop Infection In The UK

If you're diagnosed with Covid-19, it's the job of 'contact tracers' to find out who else you might have infected. Here's how they work.

Update: See the latest stories on the coronavirus outbreak.

For epidemiology expert Dr Freya Jephcott, the most important weapon against coronavirus Covid-19 isn’t hand gel, masks or soap – it’s your phone book.

There have been 36 confirmed UK cases of the infection, and the battle by health professionals to contain it has so far centred around contact tracing.

Whenever someone is diagnosed, experts face a race against time to identify the people they might have infected – before those people spread the illness themselves without knowing.

The identification of a patient in Haslemere, Surrey, has thrown experts a curveball after it became apparent the man concerned had not travelled to any areas where he might have been expected to contract the virus.

But the process for finding out exactly how he became ill remains the same, health officials told HuffPost UK.

There are currently about 400 Public Health England staff on standby across the country to quiz coronavirus patients on where they’ve been, and who with, since they fell ill. Dr Jephcott has experience in the field – a research fellow in epidemiology at the University of Cambridge and an expert in the outbreak and spread of the Ebola virus.

A woman wearing a face mask packs her suitcase in the departures area of Terminal 5 at Heathrow Airport, after it was announced British Airways had suspended all services to and from China.


She participated in the large-scale programme of contact tracing carried out in Western Africa during Ebola’s most widespread emergence in 2014 – a time-consuming and manpower-heavy process.

The search for those who may have been contaminated with Ebola in some cases required literally chasing people through thickets in Sierra Leone. By contrast, the detective work being undertaken to contain Covid-19 is rather more bureaucratic – so far, anyway. 

“It is often a case of literally sitting down for hours with a patient, going through sometimes weeks of where they have been, who they have spoken to, who they might have come into contact with – then trying to trace those people, which could throw up even more potential exposure cases,” she told HuffPost UK. 

“Couple that with a patient who is feeling ill and may need to take breaks, and you have a process that may take days and days for just one person.  It’s extremely labour-intensive and takes a huge number of people.”

It is this “shoe-leather epidemiology” that is being deployed by Public Health England – but teams are able to speed up the process by contacting potential cases by text and email if they can’t reach them immediately, and by utilising the health service’s information databases.

Dr Freya Jephcott
Dr Freya Jephcott, research fellow at Cambridge University

The pay-off can be worth it, Dr Jephcott says, as contact tracing is proven to be very effective in fighting some infectious diseases.

“In the case of Covid-19 there has been some suggestion that people may be contagious before they show any symptoms, which would likely diminish the effectiveness of contact tracing if we start to see a larger number of cases,” she added. 

“It’s really too early to tell with this particular virus. But even if contact tracing doesn’t work in completely preventing the spread of infection, it can still slow it considerably, and that’s also really important.  

“If such a virus such as this one spreads through a population very quickly, then you risk the health service becoming overwhelmed, and in turn you could see lots of people off work either sick or caring for someone who is sick too, which in turn can disrupt supply chains and other services.”

Public Health England is currently applying contact tracing from the moment a patient starts feeling ill.

It defines “close contact” with an infected person as spending 15 minutes or more within two metres of them, or holding a face-to-face conversation, and encourages those who have done so to “self-isolate” for two weeks.

But those who may have simply passed an infected person in a corridor, or at an airport or train station, are not usually contacted as the risk is thought to be minimal.

Dr Tom Wingfield, a physician and lecturer in infectious diseases, works at the Liverpool School of Tropical Medicine (LSTM).

The specialist facility is among a network across the country equipped to deal with patients diagnosed with “high consequence” infections and has treated cases of monkey pox, Mers (Middle East respiratory syndrome-related coronavirus) and Sars (severe acute respiratory syndrome-related coronavirus) in the past.

He says contact tracing is undoubtedly the best way to contain a virus when the number of diagnosed cases is relatively small, as is the case with Covid-19 in the UK. 

Liverpool School of Tropical Medicine
Dr Tom Wingfield, of the Liverpool School of Tropical Medicine

Dr Wingfield said LSTM’s process relies heavily on in-depth conversations with newly-diagnosed patients – called “index cases” – to build up a detailed picture of where they have been, who they have been with and the people who could be most at risk as a result. 

“We would ordinarily have a conversation with them about all of their movements, the people they have shared a meal with, shared a room with, or those they have just fleetingly passed.  We then assess which of those individuals who have been exposed to the virus are at higher risk and monitor them extremely closely for any signs of illness,” he added. 

“In the vast, vast majority of cases patients are more than happy to help. In the small number of cases when a patient does not want to share information, or is too ill to do so properly, we rely on information from family members [who are present] as much as we can, without breaking patient confidentiality.

“This enables us to act quickly, get treatment for the individual quickly and identify anyone else who may be at risk. It means an individual is also likely to recover much more quickly.” 

If the virus were to spread further, health officials would be likely to change tactics. However, contact tracing would still be applied if the index case were a healthcare professional, or someone else likely to have been in contact with vulnerable people. 

“It’s not possible to predict with 100% certainty how these things will develop, but contact tracing has worked extremely well in the past against other infectious diseases,” Dr Wingfield said.

“I can’t provide exact numbers, but if the volume of cases were to increase, then contact tracing may no longer be a viable activity and other approaches may be looked at.

“But we are in extremely regular contact with the network of facilities set up to deal with the potential spread of the virus, as well as Public Health England, and I think people can feel reassured that we are extremely well prepared.”