Fig. 1
From: Timeliness of contact tracing among flight passengers during the COVID-19 epidemic in Vietnam
Procedure of contact tracing for flights with COVID-19 infected cases in Vietnam. * Direct contact information: email, telephone, social media accounts. ** Indirect information: residential address, workplace address, tourism company. *** Supplementary information: temporary/permanent residential registration at local authorities, police department records, tour registration at tourism bureaus, relevant embassies, and immigration bureau data