After news of the coronavirus outbreak began to emerge from Wuhan, China, earlier this year, the Korean government activated a 24/7 emergency response system to screen all travelers entering the country from that city. A woman was stopped at Incheon Airport en route for Japan at a fever monitoring station and transferred to a hospital where she was quarantined for 14 days. The Covid-19 diagnosis was confirmed on January 20. As it happens, that’s the same day the first US case was reported.

Since the first cases were confirmed, Korean public health authorities and local governments collaborated to precisely document the movement of infected people down to the minute. Authorities sought testimony, watched closed-circuit television, investigated smartphone GPS data and more, publicizing the so-called moving histories of Covid-19 patients. All local governments share information through websites, text messages, and media. Companies have developed apps that allow users to visualize the information. Koreans can now learn where infected people went, when they were there, and how they got there. If someone learns they might have been exposed, they can quickly visit a doctor and begin self-quarantine if they have similar symptoms.

On February 4, the Korea Centers for Disease Control and Prevention took advantage of the post-MERS reform and authorized an unlicensed Covid-19 test; the government went on to test an extraordinary number of people. By February 26, Korea had tested 46,127 cases, while by that point, Japan had tested just 1,846 cases and the United States only 426.