"Over Tens of Thousands Again After Summer Vacation" ... Three Warning Signs of COVID-19 Resurgence

Weekend Two Consecutive Days Over 10,000 Confirmed Cases
Omicron Variant Surges After Resumption of International Flights
Period of Declining Vaccine and Natural Immunity Effects Arrives

The number of COVID-19 confirmed cases recorded in the ten-thousands for two consecutive days over the weekend, raising warning signs of a resurgence. With the resumption of overseas travel and the rapid influx of new variants into the country, it is analyzed that the epidemic is turning upward again around the summer vacation season. Increased use of air conditioners amid the heatwave is also cited as a factor that promotes the spread of the epidemic in indoor '3密 (close contact, closed spaces, crowded places)' environments.

According to the Central Disease Control Headquarters on the 4th, the number of new confirmed cases as of midnight that day was 6,253, nearly double the 3,423 cases reported a week earlier on the 27th of last month. This is the highest Monday figure in six weeks. On the weekend, the 2nd (announcement date), new confirmed cases were 10,715, and on the 3rd, 10,059, which were 1.6 times higher than the previous weekend. Usually, the number of new confirmed cases decreases on weekends due to reduced testing, but recording over 10,000 cases for two consecutive days clearly indicates a rebound in the epidemic.

The infection reproduction number, which was 0.74 as of the first week of June (May 29?June 4), steadily rose to 0.79 in the second week, 0.86 in the third week, and 0.91 in the fourth week, reaching 1.0 on the 28th of last month. An infection reproduction number above 1 indicates epidemic spread, while below 1 indicates epidemic suppression. With increased domestic and international movement, a rising reproduction number means the increase in confirmed cases will accelerate accordingly.

The number of imported cases among new confirmed cases is also continuously increasing. Since the 24th of last month (113 cases), more than 100 imported cases have been confirmed daily, surpassing 200 cases (206) on the 29th, with 191 cases on the 3rd and 164 cases on the 4th of this month, increasing their proportion among total confirmed cases.

Similar to Europe, detection cases of Omicron sublineage variants such as BA.2.12.1, BA.4, and BA.5 are rapidly increasing domestically. As of the 25th of last month, a total of 550 sublineage variant cases were confirmed, with 255 cases detected in the fourth week of June alone. This is more than double the 119 cases from the previous week. Lim Suk-young, head of the Central Disease Control Headquarters' situation management team, said, "As international flights continue to increase, the number of overseas arrivals is rising, and accordingly, the number of imported confirmed cases is increasing proportionally."

Immunity, which had been strengthened through COVID-19 vaccination and natural infection, is significantly weakening over time, which is also identified as a variable that can accelerate the resurgence. Even those who completed their third dose earlier this year face a considerably higher risk of infection starting this month, about 3 to 4 months later.

Professor Eom Jung-sik of the Department of Infectious Diseases at Gachon University Gil Medical Center emphasized, "By the end of this month, a clear rebound will be seen, and by autumn, there is a high possibility of 150,000 to 200,000 confirmed cases per day on average," adding, "We need to expand the introduction of oral antiviral treatments and establish additional vaccination plans for the elderly."