Q: What is meant by ‘test and trace’?

A: Test and trace is an accepted way of trying to limit the number of people each person with an infection passes it on to. This method is now being used to combat COVID-19. By testing people with symptoms, doctors find out whether they have SARS-CoV-2, the virus that causes COVID-19. If the person does have SARS-CoV-2, contact tracers then contact everyone that person has recently been in close contact with. These people are told to isolate themselves at home to stop them spreading the virus. If they develop symptoms they will also be tested.


Q: What type of test is used?

A: The common test used to assess whether you are currently infected with the SARS-CoV-2 virus uses a technique called PCR to look for the virus’ genetic material in the nose and/or throat swabs. Antigen tests, which gives a faster result can also be used. If the result is negative, it means you probably do not have the virus at the time of testing. If the result is positive, it means you are currently infected with the virus. The test does not show whether you have had COVID-19 in the past.


Q: What happens if you test positive?

A: If you test positive, you should self-isolate along with members of your household. The exact period you are advised to isolate for depends on whether you have symptoms, and which country you live in. If you have symptoms, you should self-isolate for at least 7 days after your symptoms started (UK advice) or 10 days after symptoms started (US advice). If you or your household do not have symptoms, you should self-isolate for 14 days after exposure (UK advice and US advice). Follow the instructions from your local health authority, as different countries have different advice.


Q: What happens if you test negative?

A: If you test negative, you probably do not have COVID-19. However, the test is not 100% accurate and it can take a while to become positive. So, if you have been tested because you were in contact with someone who has tested positive for SARS-CoV-2, UK advice is that you need to self-isolate for 14 days, in case you develop symptoms. However, members of your household who have also tested negative do not need to self-isolate.


Q: How does the health authority trace your contacts?

A: This system is different in different countries. In Germany, people who test positive are contacted by contact tracers, who ask how long they have had symptoms, who they have been in contact with, whether they have been at work, and whether they have school or nursery age children. They are then given a risk category, and their contacts (which could be up to around 50 per person) are traced and given advice on self-isolating for 14 days.

In South Korea, widespread testing was combined with technology to trace people’s movements through mobile phone GPS tracking and credit card transactions. People who had been close to people who had tested positive were sent messages telling them to self-isolate.

In the UK, people who receive a positive result are contacted, either by phone, email or text message and asked where they have been and who they have been in contact with recently. The information will be used to try to contact everyone the infected person has been in contact with and to advise them to self-isolate. These contacts are not told the identity of the infected person they have been in contact with. An app for contact tracing which was itself being tested to work alongside the system has not yet been rolled out.

The system differs from state to state in the US, but in most states contact tracers will call people who have been in close contact with someone who has tested positive, and tell them to stay isolated for 14 days.


Q: What should you do if you are contacted and told you have been in close contact with someone with a positive COVID-19 test?

A: You should self-isolate at home for 14 days after the day when you had contact with the person with COVID-19. It can take 14 days to get symptoms after being infected with the virus. Some countries or states may offer you a test, but not all. Even if you have a negative test, you will still be asked to self-isolate for 14 days, as the test may not have picked up the virus in the early stages of infection.


Analysis by EIU Healthcare, supported by Reckitt Benckiser


Reading list

  1. Centers for Disease Control and Prevention, US. When You Can be Around Others After You Had or Likely Had COVID-19. May 24, 2020. https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/end-home-isolation.html (Accessed 17 June 2020)
  2. Robert Koch Institute, Germany. Answers to frequently asked questions about the SARS-CoV-2 coronavirus / COVID-19 disease (infection protection measures). June 16 2020. https://www.rki.de/SharedDocs/FAQ/NCOV2019/gesamt.html (Accessed 17 June 2020)
  3. NHS, UK. Testing and tracing for coronavirus. https://www.nhs.uk/conditions/coronavirus-covid-19/testing-and-tracing/ (Accessed 16 June 2020)
  4. The Guardian. Covid-19 track and trace: what can UK learn from countries that got it right? https://www.theguardian.com/world/2020/may/21/covid-19-track-and-trace-what-can-uk-learn-from-countries-got-it-right (Accessed 16 June 2020)