The influenza (flu) epidemic, which usually peaks in the spring and dies down as the weather heats up, hasn’t slowed down this year. In fact, the number of cases has been on the rise lately, reaching the highest level in the last 20 years.

The number of patients with suspected influenza symptoms (influenza case-fatality rate) per 1,000 outpatient visits in week 20 (May 14-20) was 25.7, up 2.3 from 23.4 the previous week, according to the Centers for Disease Control and Prevention on Monday. This is a 29.1% increase from 19.9 four weeks earlier in Week 16.
The rate dipped to a low of 11.6 in Week 8 and has been steadily rising since then, driven by the start of school for school-aged children. The week 20 rate is 5.24 times the epidemic threshold (4.9).

KCDC collects influenza doctor-patient information from 196 clinics nationwide and releases the doctor-patient ratio through sample surveillance. Patients are classified as pseudo-cases if they have a cough or sore throat with a sudden fever of 38℃ or higher.

By age group, the pseudo-patient rate was highest among children and adolescents aged 13-18 years (52.6) and 7-12 years (49.1), followed by 19-49 years (28.1), 1-6 years (29.5), 0 years (17.4), 50-64 years (10.5), and 65+ years (6.5).

Flu cases tend to taper off in the spring, but this year’s epidemic has a long, thick tail.

Influenza doctor-patient ratio by age at week 20 (courtesy of the Centers for Disease Control and Prevention) /photo=News1
After peaking at 60.7 percent in the final week of last year’s seasonal influenza season (Dec. 25-31), the rate has been on a downward trend, dropping to 11.6 percent in the eighth week of this year’s season (Feb. 19-25).

At that point, it looked like the epidemic was ending, but since then, the trend has been on the rise, approaching a “double peak. Between the eighth and twentieth week, the doctor-patient ratio suddenly increased.

According to the KCDC’s Infectious Disease Clearinghouse, this year’s week 20 doctor-patient ratio is the highest since 2000, when KCDC statistics were available. During that time, the flu doctor-patient ratio was mostly in the low 5s.

The previous highest week 20 doctor-patient ratio was 11.3 in 2019, and this year’s ratio is more than double that. There have only been five other years with a doctor-patient ratio above 5: 2015 (6.6), 2016 (6.3), 2017 (7.6), and 2018 (6.0).

The persistence of the flu epidemic can be attributed to unseasonably warm weather and increased spring activity, but crucially, to the easing of COVID-19 mitigation measures.

The physician-patient ratio declined and plateaued in week 9스포츠토토, around the start of school, before rising again in week 12, when the requirement to wear face masks on public transportation was lifted (March 20).

In addition to the flu, there is also an outbreak of acute respiratory infections, which are characterized by symptoms such as runny nose, headache, phlegm, and sore throat.

The number of hospitalizations for viral respiratory infections such as adenovirus, rhinovirus, and respiratory syncytial virus (RSV) was 1,926 in week 20, which is slightly lower than the previous week (2,160) but still high.

The Korean Medical Association’s expert committee on COVID-19 countermeasures said, “Over the past three years, mask wearing and insufficient external activities have reduced our defense against basic viral and bacterial infections,” adding, “We should adhere to the principle of ‘resting when sick’ and continue to pay attention to personal healthcare.”