Attempts to stem the spread of Covid-19 are being implemented via varied means all over the world. While conclusive evidence confirming what measures work is not always apparent, two key strategies do appear to be fundamental to slowing infection rates. The first, mass testing, is self explanatory, with health experts adamant rigorous screening is a must. The second, that of contact tracing, has also received widespread media coverage, with governments including the UAE, Singapore and South Korea all espousing its success. Here, <em>The National</em> looks at exactly how the process works. This long-standing method is a little like old-fashioned detective work. A team of ‘tracers’ interview newly-infected people about where they have been and who they have been in contact with. They then track those people down too, to interview and test them for the virus. This continues until everyone who has been exposed to the initial infection is identified and isolated. Significantly, despite this method proving its worth in the past, contact tracing for Covid-19 has proved much harder compared to outbreaks like Sars and Mers. This is because Covid-19 sufferers can be asymptomatic, infecting others before they even develop symptoms. Since the very first four cases of coronavirus were detected in the Emirates in late January. At the time, authorities announced they would be retracing the family’s steps to see who they had come into contact with. Days later, in early February, the country already had 500 people working “round the clock on communication, medical investigations and logistical support related to combating the virus”. At the time, the UAE’s health minister, Abdulrahman Al Owais, said about 150 people were tested for each of the confirmed patients. According to a number of media briefings in late March and early April, contact tracing was responsible for the identification of hundreds of cases in the UAE. Yes. Authorities used the same method to limit the spread of Mers, a coronavirus that is a cousin of Covid-19. The first case of Mers was detected in the country in July 2013. Since then there have been 89 cases in the UAE. According to a WHO report into one of the latest cases from last October the country tracked down and tested 61 contacts, including 57 health care workers and four farm employees who lived in the same household as the 44-year-old farmer in Al Ain who had been confirmed as having Mers. Everyone was tested for the virus at the time, but their results were negative. Absolutely. As the outbreaks have grown, it has become harder to manually track and trace each contact. So some governments have invested heavily in applications that can do the tracking for them. One recent study by researchers at the University of Oxford suggests tracking apps can be effective in reducing infection rates, even when only 60 per cent of the population adopts them. In South Korea, the movements of everyone who tests positive are tracked through an app. Anyone nearby receive social distancing alerts via their smartphones. The country, which as of April 12 had 10,500 cases, confirmed its first infection of Covid-19 on the same day as the United States, which now has more than half a million infections. Singapore recently made the code for its contact tracing app, called TraceTogether, available to developers around the world. It can identify people who have been within two metres of coronavirus patients for at least 30 minutes using Bluetooth technology. If a user becomes infected, authorities can quickly identify others they have been in contact with, which allows them to isolate them quickly. This helps get around another potential problem related to manual contact tracing: human memory, which is imperfect. Yes. Apple and Google recently announced they will be teaming up to introduce contact tracing technology as part of a rare collaboration. It will allow smartphone users on the iOS and Android platforms to opt into a system which alerts them if they have been exposed to a person who tested positive for the virus. The system, which works using Bluetooth technology, will also share information from health authorities on what to do next. It does not collect personally identifiable information or user location data.