【Seoul, South】COVID-19 Resurges… “KP.3 Variant Has High Immune Evasion Ability, Strong Transmission Power”

Editor’s Note

As COVID-19 cases rise with the new KP.3 variant, health authorities note a recurring summer pattern. While severity remains low, this report underscores the importance of sustained personal hygiene even as the pandemic evolves.

한 시민이 코로나19 검사를 받고 있는 모습. 2023.1.19/뉴스1 ⓒ News1 신웅수 기자
New Variant KP.3 Rapidly Spreading… KDCA “Repeating Summer Epidemic Pattern”
“Severity and fatality rate are not high, but personal hygiene rules must be followed.”

(Seoul=News1) Reporter Cheon Seon-hyu — “Sigh… I got it again. It’s already the third time. What else could it be? COVID-19.”
The number of COVID-19 patients, which seemed to have disappeared since last winter, is rapidly increasing. Not only are people who have tested positive for COVID-19 easily found around, but also more people are taking out masks they had put away in drawers and wearing them again due to the rapid spread.
Doctors also said they are feeling the increasing number of COVID-19 patients.
An internal medicine specialist operating a clinic in Seoul said,

“COVID-19 patients have really increased a lot,” and “I continue to see about 30-40 positive patients a day.”

A private practitioner in Suwon, Gyeonggi Province also said,

“The number of patients coming for COVID-19 tests has increased, and the number of patients testing positive has also increased,” and “It seems to be spreading again as a new variant has emerged and summer has arrived.”

According to the Korea Disease Control and Prevention Agency (KDCA) on the 7th, the number of patients hospitalized for COVID-19 from June 21 to 27 (week 30) was 465, a twofold increase compared to the previous week (226).
Looking at the epidemic trend, after peaking in the first week of February, it continued to decline until the fourth week of June (week 26) with 63 cases, then reversed to 91 cases in early July (week 27), and increased to 148 cases in week 28 → 226 cases in week 29 → 465 cases in week 30. It surged about 5.1 times in four weeks.
According to the KDCA, the virus currently in circulation is the new variant KP.3. The detection rate of JN.1, which had been dominant since January, decreased by about 40 percentage points from 59.3% in June to 19.5% last month, while the proportion of the new variant KP.3 increased by 27.78 percentage points to 39.8% compared to June (12.1%).

What are the symptoms when infected with KP.3?

A KDCA official explained,

“According to the U.S. Centers for Disease Control and Prevention (CDC), the symptoms are no different from the COVID-19 variants experienced so far, and the severity and fatality rate are not high,” but “the CDC says KP.3 shows a slightly different immune evasion ability.”
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Immune evasion refers to the virus evading the human body’s immune response system.
This means that even people who have been previously infected with COVID-19 or have antibodies from vaccination can be reinfected with COVID-19 if a virus with immune evasion ability invades the body. In other words, it means transmission power has strengthened.
Accordingly, the KDCA formed a Respiratory Infectious Disease Response TF on June 22 to monitor the spread of COVID-19, whooping cough, mycoplasma pneumonia, etc.
However, health authorities say that based on overseas cases like the U.S. and Japan, which have already experienced the KP.3 epidemic since last year, and Korea’s COVID-19 epidemic pattern, there is no need for excessive fear regarding this spread.
Kim Dong-geun, head of the KDCA’s Respiratory Infectious Disease Response TF, said,

“In fact, this epidemic pattern is not unique to this year; in 2022 and 2023, patients always increased in the summer,” and “The pattern of one epidemic in winter and one in summer is continuously repeating.”

He added,

“However, this epidemic seems to be a combination of factors including the new variant, vaccination, and indoor ventilation issues.”

Indeed, Korea has shown a pattern of increasing COVID-19 patient numbers in summer and winter.
On top of this, the emergence of KP.3 with good immune evasion ability, and factors like not yet receiving vaccines effective against KP.3, are overlapping, leading to the rapid spread of patients.
Yang Jin-seon, head of the KDCA’s Infectious Disease Management Division, said,

“If confirmed cases and deaths had significantly increased in countries like the U.S., UK, Europe, and Japan where KP.3 has already been prevalent, we would have been very tense, but as of now, there is no need to be overly anxious.”

However, he urged efforts to prevent spread by complying with personal hygiene rules and paying attention to indoor ventilation.
Director Yang urged,

“As hot weather continues, not ventilating enclosed spaces and running air conditioners creates an environment where respiratory infectious diseases easily spread,” and “Please follow quarantine rules such as ventilating every 2 hours and wearing a mask if you have respiratory symptoms.”

Additionally, the KDCA is planning vaccination against the JN.1 virus, the ancestor of the KP.3 variant, in October.

2020년 1월~2023년 8월 국내 코로나19 발생·사망 보고현황. 그래프 추이를 보면 여름철과 겨울철에 환자와 사망자 수가 증가하는 것을 확인할 수 있다. (질병청 제공)

The vaccine administered in the first half of this year was effective against XBB.1.5, which was prevalent last winter and fall, but the preventive vaccine for JN.1 is known to be effective even against the currently circulating KP.3 or KP.2.

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⏰ Published on: August 07, 2024