Last Year's Disappeared Flu Could Be More Dangerous Than COVID-19 This Year

Domestic Flu Patients Last Year at One-Fifth of Previous Year
Flu Also a Respiratory Disease Like COVID-19
Winter High-Intensity Quarantine Measures Slow Spread
Low Flu Exposure Leads to Immunity Deficiency
Experts "Flu Cases Will Increase if Winter Quarantine Measures Ease"

On the morning of the 15th, citizens are waiting to receive COVID-19 screening tests at the temporary screening clinic in the public parking lot of Sinchon Train Station, Seodaemun-gu, Seoul. / Photo by Yonhap News

[Asia Economy Reporter Lim Juhyung] "This winter, due to the flu and respiratory disease outbreaks, up to 60,000 people could die in the UK alone."

As the COVID-19 variant virus pandemic continues, warnings have emerged that if the flu returns this winter, the number of deaths could surge dramatically. Last winter, when COVID-19 spread severely, various respiratory diseases including the flu suddenly disappeared, but it is expected that they may resurge this year. There are concerns that if the so-called 'twindemic' (twin + pandemic), where COVID-19 and the flu spread simultaneously, occurs, the damage could become uncontrollable.

According to a report from the UK medical journal 'Academy of Medical Sciences,' if seasonal flu and various respiratory diseases spread together this winter, the healthcare system could collapse, resulting in about 60,000 deaths in the UK alone.

The reason why the flu, which returns every winter, can cause such fatal outcomes is because of COVID-19. Winter is originally a busy time for hospitals due to children and the elderly catching the flu every year, but if the COVID-19 outbreak does not subside, there is a risk of national healthcare system collapse.

Another reason is that the number of flu patients last year decreased compared to usual years, leading to a reduction in overall population immunity. According to data compiled by the World Health Organization (WHO) in January, the activity level of the flu virus last winter dropped to summer levels. In the United States, the hospital visit rate of flu patients was 1.6%, which is 1.0 percentage point lower than the baseline of 2.6%.

A pediatric clinic in Seoul where last year's flu vaccinations began / Photo by Yonhap News

In South Korea as well, the number of flu patients significantly decreased. According to the Korea Disease Control and Prevention Agency, the number of flu patients per 1,000 outpatients last winter was 2.6, only one-fifth of the 12.7 recorded in the same period the previous year. Despite the free flu vaccination rate dropping by 9.1 percentage points from 73.1% in 2019 to 64.0%, the number of flu patients decreased.

Scientists speculate that quarantine measures to prevent the spread of COVID-19 may have influenced the reduction of the flu virus. Dr. Ailey Klein, an emergency medicine physician at Johns Hopkins University in the U.S., explained, "Since the flu is also a respiratory infectious disease like COVID-19, quarantine guidelines aimed at slowing COVID-19 infection can also slow the spread of the flu."

The problem is that the flu virus, which had reduced activity last year, is likely to return stronger this year. This is because the overall population immunity to the flu has decreased. Regarding this, Dr. Klein pointed out, "Thanks to everyone’s efforts in hygiene management and adherence to quarantine measures (such as lockdowns) during winter, the number of people exposed to the flu decreased," but added, "Therefore, immunity to the flu virus is almost nonexistent."

He continued, "If restrictions are lifted in the winter of 2021 and many people are exposed to the flu, it could lead to more severe illnesses due to weakened immunity."

Mask Mandate Notice / Photo by Yonhap News

Experts emphasize that the timing when COVID-19 quarantine measures are relaxed may coincide with the flu outbreak, highlighting the importance of the government’s establishment of winter quarantine guidelines.

Professor Kim Woojoo, an infectious disease specialist at Korea University Guro Hospital, explained, "The reason the flu decreased last winter is related to COVID-19. Because of COVID-19 prevention measures such as bans on private gatherings and mask-wearing, the flu did not spread either," adding, "COVID-19 should be considered a constant factor in flu spread."

He added, "If COVID-19 quarantine measures are eased, flu cases could increase at any time accordingly."

Professor Steven Holgate of the University of Southampton in the UK recently proposed measures to prevent a winter twindemic in a report. He suggested △ maintaining some quarantine guidelines such as social distancing and mask-wearing △ operating clinics that conduct simultaneous testing for flu and COVID-19 △ securing additional hospital beds during winter as possible solutions.