Trend of Norovirus Infection Cases by Age Group Over the Last 5 Weeks [Provided by Korea Disease Control and Prevention Agency]

The number of norovirus infection cases, which primarily occur in winter, has increased by nearly 60% compared to the same period last year, centering around infants and young children.

According to sample surveillance conducted by the Korea Disease Control and Prevention Agency (KDCA) on 210 hospital-level medical institutions, there were 127 norovirus cases in the 48th week of this year (November 23-29). This represents a 58.8% increase from 80 cases during the same period last year.

Norovirus cases have been on a continuous upward trend for four consecutive weeks since the 45th week (70 cases).

As of the 48th week, the age group of 0-6 years accounted for 38 cases, or 29.9% of the total. Patients aged 7-18 years also numbered 33 cases (26%).

In Korea, norovirus primarily occurs from winter to early spring of the following year (November to March).

It particularly occurs centering on infants and young children (0-6 years), who have difficulty with personal hygiene management and frequently engage in group activities.

Norovirus has diverse viral genotypes and the duration of immunity after infection is short, lasting up to approximately 18 months, meaning re-infection is possible even after a previous infection.

Infection typically occurs after consuming contaminated water or food, such as seafood. Person-to-person transmission through contact with infected individuals is also possible.

Symptoms of norovirus infection, such as vomiting and diarrhea, appear within 12-48 hours. Some individuals may also experience abdominal pain, chills, and fever.

To prevent infection, it is recommended to wash hands thoroughly with soap for at least 30 seconds, rather than using hand sanitizer. Food ingredients should be washed with running water and cooked thoroughly at 85 degrees Celsius or higher for at least one minute.

Individuals with norovirus infection should refrain from attending school or work for up to 48 hours after their symptoms disappear and should use separate bathrooms and living spaces from other family members.

When using the toilet, it is advisable to close the toilet lid when flushing after defecation to prevent the spread of norovirus through aerosols.

 Korea Disease Control and Prevention Agency