Nature wades through the literature on the new coronavirus — and summarizes key papers as they appear.

10 July — Massive contact-tracing effort finds hundreds of cases linked to nightclubs

Mobile phone and credit card data helped to identify nearly 250 coronavirus infections linked to a fast-moving outbreak that began in a popular nightclub district in Seoul.

Soon after South Korean nightclubs reopened 30 April, public-health officials noted a cluster of COVID-19 cases among people who had visited Seoul’s Itaewon club district. Jin Yong Lee at Seoul National University Boramae Medical Centre and his colleagues used mobile phone location data, credit card payment records and other information to identify more than 60,000 people who had spent time in or near Itaewon clubs (C. R. Kang et al. Emerg. Infect. Dis. http://doi.org/gg4fhj; 2020) in late April or early May. All were encouraged to undergo testing for SARS-CoV-2.

By late May, officials had tested more than 40,000 people. The effort turned up 246 infections — including several that were 3, 4 and even 5 steps along the transmission chain from club-goers.