BA.2.75 makes its first known local transmission

People entering Korea from abroad line up to get tested for Covid-19 at Incheon Internation Airport on Monday. [NEWS1]

Korea on Monday confirmed its first locally-transmitted case of the Omicron subvariant BA.2.75, nicknamed Centaurus, the most contagious version yet.

According to the Central Disease Control Headquarters, the patient is a person in their 20s living in North Chungcheong, who received three vaccine shots.

After showing symptoms, the patient tested positive for the virus on July 13, and was released from quarantine after seven days of home treatment.

The confirmed patient was an acquaintance of Korea’s second BA.2.75 case, a non-Korean national in their 30s living in North Chungcheong who arrived from India on July 5.

The new patient picked the other patient up at the airport and rode home in the same car, the provincial government of North Chungcheong said.

Given this transmission route, authorities believe this to be the first case of locally transmitted BA.2.75. An epidemiological investigation is underway to find out if there are any more infections.

This brings the country's total BA.2.75 cases to four, including one imported case and three domestic cases, yet it remains unclear how the other two patients contracted the strain.

Already battling a Covid-19 surge fueled by the highly contagious Omicron subvariant BA.5, BA.2.75 spells even worse news for Korea.

BA.2.75 has eight more spike protein mutations than the BA.2 variant, or Stealth Omicron, which means that it binds to cells more effectively and evades antibodies formed by vaccines. It appears to spread even faster and evade vaccine-acquired immunity better than BA.5, which is now the dominant variant in Korea.

After being discovered in India for the first time in late May, BA.2.75 is spreading in at least 15 countries including in Europe and the United States.

Monday’s new Covid-19 cases stood at 35,883, according to the Korea Disease Control and Prevention Agency (KDCA), the highest figure for a Monday in 13 weeks.

It was 1.36-times larger compared to a week ago, and 2.83-times larger than two weeks ago.

The number of severe Covid-19 cases — those who require oxygen treatment (such as high-flow oxygen therapy), mechanical ventilation (being put on a respirator), extracorporeal membrane oxygenation (ECMO) or continuous renal replacement therapy (CRRT) — totaled 144 as of Sunday midnight, which rose by 1.77 times from the previous week.

Amid concerns that the coming virus wave may be greater in size than initially expected, the government partly strengthened virus curbs that went into effect from Monday.

PCR tests for incoming international travelers, which could be conducted within three days of arrival, now need to be taken within a day of arrival.

They are technically required on the day of arrival, but in cases when this is impossible, a test on the next day will be accepted.

Face-to-face visits in nursing homes and psychiatric hospitals were banned once again from Monday.

Outings for patients are only allowed for essential outpatient treatment, employees working at the facilities have to get tested for Covid-19 once in a week.

BY SEO JI-EUN [seo.jieun1@joongang.co.kr]