Seasonal Flu Silent for 2 Years, Warning Signs of Concurrent Outbreak with COVID-19

Late Summer Increase in Suspected Influenza Cases
Health Authorities Preparing Response Plan Including Vaccination

Although the resurgence of COVID-19 has shifted to a declining trend, the number of seasonal flu (influenza) patients, which had been quiet until now, is increasing, raising concerns that both the flu and COVID-19 could spread simultaneously this fall. Health authorities have stated that the flu also poses a higher risk of severe illness for high-risk groups such as the elderly and those with underlying conditions, and have decided to start free flu vaccinations for children and the elderly from late this month.

According to the Korea Disease Control and Prevention Agency on the 7th, the number of influenza-like illness (ILI) patients per 1,000 outpatients was 4.3 in the fourth week of last month (August 21?27), up from 4.2 in the third week of August. ILI patients are those showing symptoms such as high fever along with cough or sore throat. Earlier, the numbers were 3.3 in the first week and 3.7 in the second week of August.

Experts diagnose this as a relatively high level compared to typical summer influenza patient occurrences. In the fourth week of August in 2018 and 2019, the ILI patient numbers were 3.7 and 3.5 respectively, while during the same period in 2020, after the onset of COVID-19, it dropped to 2.0, and further down to 0.9 in 2021.

Since the spread of COVID-19, strengthened preventive measures such as mask-wearing and refraining from gatherings led to no seasonal flu outbreaks in the fall and winter of 2020 and last year. However, since social distancing measures were eased and outdoor activities increased after April, the flu virus appears to be spreading again. Early flu outbreaks have already been confirmed in Southern Hemisphere countries such as Australia and New Zealand. Moreover, with the public’s flu immunity currently lowered and the ongoing COVID-19 pandemic, health authorities explain that there is a high possibility of simultaneous spread of the two infectious diseases.

Im Suk-young, the Situation General Manager of the Central Disease Control Headquarters, explained yesterday, "Winter is the flu season, and with relatively more indoor activities, respiratory infectious diseases can spread more easily. Therefore, there is a high possibility that COVID-19 and influenza will spread simultaneously." Im added, "We are establishing response plans including influenza vaccination and will announce them soon."

The summer resurgence of COVID-19 that began in July has clearly entered a declining phase, but a winter resurgence may occur again. However, since this resurgence happened earlier than initially expected and on a relatively large scale, and immunity and vaccination effects have accumulated, many analyses suggest that the next wave will occur around early next year on a smaller scale than before.

Im said, "We initially expected the resurgence to come in fall or winter, but since we experienced a somewhat large resurgence earlier in the summer, we expect the next resurgence to come later than fall or winter. Because immunity within the population is relatively high, the possibility of a significant change in a short period is low."

Jung Jae-hoon, a professor of preventive medicine at Gachon University College of Medicine, said, "Considering that immunity gained through infection or vaccination continuously decreases, a medium-scale outbreak may occur with the emergence of the next variant, but it is unlikely that the scale of the outbreak will be larger than this resurgence. The timing of the next outbreak could be as early as December this year or as late as March next year."

This content was produced with the assistance of AI translation services.