Health authorities repeated its warnings on concurrent outbreaks of the seasonal flu and COVID-19, as the latter's infection reproduction number surpassed one for the first time in nine weeks.

Second vice health minister Lee Gi-il during a COVID-19 meeting on Friday called on authorities to prepare for a so-called “twindemic,” noting that the reproduction number stands at one-point-09.

The number indicates how many people one person infects with the virus; if it exceeds one, it means the virus is spreading and the transmission is growing.

This comes as experts, including Jung Ki-suck, the head of the nation's expert advisory panel on infectious diseases, previously warned that the nation may see a dual outbreak in November or December.

The vice minister also called for vigilance against the influenza, saying six-point-two out of every one-thousand outpatients had the flu as of the second week of October, higher than the standard of four-point-nine.

He then urged seniors and children, who are more prone to suffer from severe flu symptoms, to receive their flu shots.