Extensive contact-tracing was used to identify and contain an outbreak of COVID-19 in South Korea that was linked to Seoul's LGBTQ+ nightclubs. Authorities relied upon cellular location data, credit card payment history, GPS data, drug utilization review, public transportation records, and closed-circuit television footage. The national effort raised concerns over discrimination against and privacy violations of South Korea's LGBTQ+ community, even though it was effective in containing the outbreak.