The number of patients infected with influenza (flu) and norovirus, typical infectious diseases that trend during winter, has doubled in just a week. Both infectious diseases thrive as human contact increases during the year-end and New Year holidays, making it crucial to adhere to hygiene and prevention guidelines for infectious diseases.
According to the Korea Disease Control and Prevention Agency on the 27th, for the period from the 15th to the 21st of this month (week 51), there were 31.3 influenza patients per 1,000 outpatient visits, a 2.3-fold increase from 13.6 in week 50. This figure approaches four times the threshold of 8.6 for the 2024-2025 influenza season. Influenza patients refer to those with sudden fevers of 38 degrees Celsius or higher, cough, or sore throat.
The number of influenza patients during this season maintained an average in the 4s but surged significantly over the past five weeks, starting from the 17th to the 23rd of last month (week 47). In week 51, it jumped to 31.3.
During this period, the number of hospitalized influenza patients also increased. From 67 patients hospitalized from the 24th to the 30th of last month (week 48), the number rose to 409 in week 51.
The Korea Disease Control and Prevention Agency has been conducting the national influenza vaccination for the 2024-2025 season since September as a precaution against influenza. Vaccinations will be available until April 30 next year.
The trend of norovirus infection patients is also on the rise. According to the agency, the number of norovirus patients increased from 69 in week 47 to 247 in week 51, a 1.7-fold increase.
The agency emphasized caution regarding norovirus. This is due to recent outbreaks of norovirus-related food poisoning incidents occurring nationwide. In Gwangju this month, there were a total of three food poisoning cases reported; investigations found norovirus in two of them. Additionally, according to the Incheon Health and Environment Research Institute, soldiers belonging to a unit in Incheon complained of food poisoning symptoms last month, which were confirmed to be caused by norovirus.
Norovirus food poisoning often occurs by ingesting food or groundwater contaminated with norovirus, or through transmission via contact with feces, vomit, saliva, or contaminated hands of an infected person. Therefore, strict hygiene management during food preparation is essential. Norovirus can survive at temperatures as low as minus 20 degrees, so shellfish, including raw oysters, must be sufficiently cooked.
Health authorities stressed that maintaining hygiene practices is the most important way to prevent influenza and norovirus infections. In particular, because there is no preventive vaccine for norovirus, extra attention to hygiene management is necessary.
Yang Jin-sun, head of the Infectious Disease Management Division at the agency, noted, “Norovirus can be transmitted not only through raw oysters but also by every food and by carriers. Even if infected, individuals often do not realize they are infected in the early stages and may continue preparing food, so it is crucial to maintain thorough hygiene of cooking tools such as knives and cutting boards.”