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Coronavirus (COVID-19) Expert interview: What is contact tracing?

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The COVID-19 outbreak is a rapidly evolving situation and information and guidance is therefore updated frequently. This blog was last updated on 13 February 2020 and the information below has since been superseded.

Please visit for the latest health advice or for all other information.

One of the ways we protect the public from infectious diseases like novel coronavirus (COVID-19) is contact tracing. In this blog Nick Phin, Deputy Director at PHE’s National Infections Service answers some questions about how this works.

For more information about novel coronavirus see our regularly updated Q&A blog.

What is contact tracing and how are we using it to tackle novel coronavirus?

So far in the UK we’ve seen a small number of novel coronavirus cases.  At the moment we undertake contact tracing to prevent the infection spreading further. Contact tracing is a fundamental part of outbreak control that’s used by public health professionals around the world.

If a person tests positive for novel coronavirus, we speak to the patient to identify anyone who has had close contact with them during the time they are considered to be infectious and go all out to find these people as soon as possible.  Once we have made contact with them we can then give them the advice they need. If they are in groups considered to be a higher risk, we make sure that we follow up with them on a daily basis to see how they are.  If they become unwell we are then able to assess them quickly and take appropriate action.

When we identify a UK case linked to another country or territory, we’ll notify the public health authorities there so that they can investigate potential contacts and take steps to prevent further cases. Equally, if any public health authorities in other parts of the world are investigating an outbreak and find a link to the UK, they’ll notify us, either directly or through the World Health Organization. We’ve blogged in the past about how we successfully used contact tracing to follow up after a case of a different type of coronavirus called MERS-CoV.


How does contact tracing work?

Specialist labs will quickly test anyone suspected of having the novel coronavirus and, if someone is found to have the infection, a clinician will speak to them to gather details of places they visited and the people they’ve been in contact with since they became unwell or, in the case of international travellers, since they arrived in the UK.

We use this to build up a detailed picture of the people we need to get in touch with, such as family members, colleagues or fellow travellers.

When we talk about “close contact” it’s important to point out that we’re not looking for people the person may have passed on the street or in a shop, as the risk in these situations is very low. A close contact involves either face to face contact or spending more than 15 minutes within 2 metres of an infected person.

Once we have recorded the close contacts the patient had, we can categorise them into high or low risk, then contact them to provide advice on what they should do.  Obviously, family members or work colleagues are easier to find, but for international visitors we may need to source information from airlines or Border Force, for instance.

What advice is given to the close contacts?

When we get in touch with a contact we provide them with advice on what to do if they become unwell or develop certain symptoms.  This way they can speak to the right health expert, so that the right advice can be given and right action taken .

If we believe a contact is at higher risk of infection they may be asked to self-isolate, remaining in their home and staying away from work, school or public places and we contact them daily until they can be given the all-clear.

If the person being monitored does develop symptoms, we would test them and provide them with specialist care if they have the novel coronavirus.

How do you know contact tracing works?

Contact tracing is a tried and trusted approach that has been used for many years to prevent the spread of infection and to contain and stop outbreaks

The confirmed novel coronavirus cases linked to an individual from Brighton were all rapidly identified through PHE’s comprehensive contact tracing approach, tested quickly and provided with appropriate support.

Why don’t you release information about the exact whereabouts of confirmed cases to help reach potential contacts?

In the majority of cases it’s not necessary to release these details as we can gather the information we need and approach people who we believe to be at risk directly and quickly.

And of course, we have an overarching duty and obligation to maintain patient confidentiality.  For this reason we would only release information that could identify individuals in exceptional  circumstances.

If we believed it was necessary, we would use the media or social media to help us get in contact with people.

How will PHE cope with demand if more coronavirus cases are confirmed?

Our experts have considerable experience at using contact tracing to prevent and contain outbreaks and to keep the public safe.

However, it does involve a lot of resources so as part of our comprehensive approach to tackling novel coronavirus in the UK, we’re putting extra resources into our contact tracing efforts. If the virus becomes established in the UK then we may need to move to a different phase of the response which focuses less on containment – but we are a long way off that.

How long will contact tracing continue?

All aspects of our response to novel coronavirus are kept under constant review and informed by a range of public health experts and scientists.

Contact tracing may continue for many weeks and successfully contain the virus, or we may reach a point where we are seeing sustained transmission, at which point there would be less emphasis on contact tracing as a key element of the response.

Dealing with large outbreaks and new infections is something we have prepared for over many years.  Other measures we may use include increasing the emphasis on public health messaging, such as advising people to wash hands frequently or catch their coughs and sneezes with a tissue.

We plan for many eventualities and are ready to take all proportionate and necessary measures to keep the public safe.

What can I do if I’m worried about catching novel coronavirus?

We are still learning about novel coronavirus, but we know that similar viruses spread through droplets produced by coughing and sneezing.

There are a number of simple actions we can all take to help stop germs like novel coronavirus spreading:

  • Wash your hands often with soap and water, especially after using public transport. Use a sanitiser gel if soap and water are not available.
  • Avoid touching your eyes, nose and mouth with unwashed hands.
  • Avoid close contact with people who are unwell.
  • Always carry tissues with you and use them to catch your cough or sneeze, then bin the tissue and wash your hands (or use a sanitiser gel).

Download public information materials on good hygiene from PHE's campaign resource centre.

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