The US Centers for Disease Control and Prevention (CDC) upgraded its travel alerts to South Korea on stage 24, the highest level, with respect to Coronavirus Infection-19 (Corona 19).

The CDC posted on its homepage a trip alert for Korea as a three-stage warning and advised its citizens to refrain from unnecessary travel on the grounds of widespread community dissemination.

"The development of respiratory diseases caused by coronavirus infection-19 is widespread," the CDC said. "The elderly and chronically ill may be at higher risk for serious illness."