Disease Detectives: the 101 of Contact Tracing

How do we control an easily spread disease without a vaccine or strict, permanent lockdown measures? Contact tracing. Australia launched its contact tracing app this week (Apr 27th), and with the UK to follow in a few weeks, it’s time to explore what contact tracing is and how it has been used before.

As we come to the end of our second set of lockdown weeks in the UK, governments across the globe are beginning to outline what the easing of measures may look like. As a country which has not been too heavily hit by covid-19, Australia is one of the first to ease it’s strict lockdown measures. The country has reported only 90 deaths due to covid-19, with areas such as Sydney impacted more (as London has been in the UK). Australia is well past the peak of the disease now and ready to lift some lockdown measures, slowly. To aid this, the government are encouraging the public to download a contact tracing app, COVIDSafe. The website states: “The COVIDSafe app is part of our work to slow the spread of covid-19. Having confidence we can find and contain outbreaks quickly will mean governments can ease restrictions while still keeping Australians safe.” So what is contact tracing?covidsafe

In February 2020, a blog entry was uploaded to the UK government’s public health website detailing how contact tracing could be used to tackle covid-19. The basic idea of contact tracing is for an individual, who tests positive, to list all those they have been in close contact with during the time they were likely to be infectious. Using this information, these individuals can be contacted or regularly checked upon if they are in a high risk category, to see if they too become ill. If any of these people subsequently fall ill, they can be tested quickly (in theory) and receive care faster as they are more likely to have the disease. Close contact is classed as face-to-face contact, or spending more than 15 mins within 2 metres of an infected person. Traditionally contact tracing is conducted by individuals, contact tracers (or disease detectives): these are the people who track and trace the spread of a disease from an individual, following up and contacting those at risk of catching the disease.covidtracingapp

Another segment of the post read: “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.“- again, that was back in February. Whilst they do not specifically detail what another phase may be, it could include the use of a covid-19 contact tracing app, and with the UK government’s announcement of such an app in use 3 weeks from now, I’d say it’s quite likely this is part of phase II. If the app is like the Australian version, it will run in the background of your device, using Bluetooth to recognise if you have come into contact with another person (also using the app). The app may log the time, date, distance and duration of contact, but may not collect exact location data. The information is encrypted and may be stored for 21 days. If someone you have been in contact with tests positive, contact tracers will be able to use the app data to get in touch with those people affected and provide advice for next steps (e.g. self-isolation etc.). The UK government is currently recruiting more contact tracers to work alongside this app.covidtracing

Although not used on an international scale before, contact tracing and disease detectives are not new. I teach a course through The Brilliant Club entitled Disease Detectives, all about how we can prevent the spread of diseases, treat those with diseases and track outbreaks. An example of contact tracing in use in the UK was in 2018, when an individual in Leeds tested positive for MERS (Middle East Respiratory Syndrome – another from the coronavirus family). While there have only been 5 confirmed cases of MERS in the UK, public health England (PHE) are aware of its dangers, and track it closely. In 2018, the individual flew to the UK from the Middle East and was the first reported case since 2013. A national incident was declared, and contact tracers had to inform family members, passengers in close proximity on the plane, and healthcare workers who had been in contact with the patient, to watch for symptoms over the next 14 days. This quick response meant there was no onward transmission. Other diseases which have benefited from contact tracing are Ebola, and sexually transmitted diseases such as HIV.

What does this mean for us? We are well beyond a handful of covid-19 cases in the UK, but contact tracing, helped by an app, could provide a safe and effective way to aid the slow lifting of restrictions. The deaths linked to a sustained financial crash could quickly surpass those linked to covid-19 and therefore, the government will need to carefully formulate a way to start the economy moving with social-distancing still in place, and a contact tracing app could really help. Here are two open access papers if you wish to read further about contact tracing, both provided by the Royal Society: 2003 and 2005. Watching how different countries approach this period could show us how the UK may choose to proceed, but only time will tell. It is a waiting game dictated by covid-19.

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