The Korea Disease Control and Prevention Agency (KDCA) is reportedly considering adjusting the vaccination schedule for high-risk groups, such as the immunocompromised, ahead of the national influenza vaccination campaign slated for the 21st.

"We are discussing specific targets and detailed schedules regarding the adjustment of the vaccination schedule," a KDCA official said. "We plan to make a decision next week by comprehensively considering vaccine supply schedules and expert opinions."

The review of the schedule adjustment comes as the influenza epidemic has arrived earlier than usual.

In fact, as the flu epidemic has continued since late August, the KDCA issued an influenza advisory on the 11th of this month—more than a month earlier than the previous season.

Last year, the advisory was issued on October 17.

According to infectious disease sentinel surveillance statistics, the number of influenza patients hospitalized in hospital-level medical institutions surged by more than 200, from 78 in the second week of last month to 300 in the first week of September three weeks later.

The proportion of patients suspected of influenza infection stood at 25.3 per 1,000 outpatients, an increase of nearly fourfold compared to 6.6 during the same period last year.

Hospitalized COVID-19 patients also increased about 3.4-fold from 57 to 193 over the same period.

Amid a steady rise in hospitalized COVID-19 patients as well, concerns are rising in the medical community over a "twindemic," a simultaneous outbreak of both influenza and COVID-19.

A professor of infectious internal medicine at a university hospital advised, "If a high fever persists for more than three days, does not subside even after taking fever reducers, or is accompanied by symptoms such as difficulty breathing, chest pain, or cyanosis, you should visit a medical institution immediately."

Reported by Kim Jiuk | Video by Lee Eui-seon | Graphics by Yook Do-hyun | Produced by SBS Digital News