The index case imported from abroad in the fifth group involved Patient #16, a 42-year-old woman who developed chills on January 25th after visiting Thailand and tested positive on February 4th. Since Patient #16 developed symptoms after visiting Bangkok and Pattaya, Thailand, between January 15th and January 19th, it is probable that she was either infected at a tourist destination in Thailand or Bangkok airport. The daughter of Patient #16 tested positive on February 5th and was designated as Patient #18. Among the other family members who dined with Patient #18 at her mother’s house on January 25th, the older brother (Patient #22) tested positive for COVID-19 on February 5th. Patients #18 and #22 were initially asymptomatic. Hence, the date of symptom onset could not be estimated. Moreover, Patient #18 had an overlapping history of visiting Thailand and a hospital visit with Patient #16 in Korea thus, the route of transmission was unclear and remained under investigation.