To clarify transmissibility of the severe acute respiratory syndrome coronavirus 2 Omicron variant, we determined serial intervals and secondary attack rates among household contacts in South Korea. Mean serial interval for 12 transmission pairs was 2.9 days, and secondary attack rate among 25 households was 50.0%, raising concern about a rapid surge in cases.
Keywords: 2019 novel coronavirus disease; COVID-19; Omicron; SARS-CoV-2; South Korea; coronavirus disease; respiratory infections; severe acute respiratory syndrome coronavirus 2; variant of concern; viruses; zoonoses.