New variants are spreading, quarantine lifting is reconsidered

A Covid-19 testing center outside Seoul Station, central Seoul, is quiet on Tuesday as Korea reported the lowest Covid figure reported on a Tuesday in 15 weeks at 35,117 new cases. [WOO SANG-JO]

New Omicron subvariants driving Covid-19 spikes in South Africa and the United States are emerging in Korea, with the government reconsidering whether to lift the seven-day mandatory quarantine requirement for infected people set to be lifted next week.

The Korea Disease Control and Prevention Agency (KDCA) announced in Tuesday’s press briefing that it has detected three cases in Korea of new Omicron subvariants BA.4 and BA.5.

One person who arrived from South Africa on April 27 was confirmed to have the BA.4 variant.

Of the two cases of the BA.5 variant, one was a local case of an asymptomatic patient in Incheon who tested positive on May 12. It was detected as part of the country’s boosted surveillance of virus variants, and investigation is underway on the infection route, health authorities explained.

The other BA.5 case was a traveler from Turkey, who entered Korea on May 8 and was confirmed to have the subvariant on May 12.

Both subvariants were first reported by South Africa and have become the dominant variants there, with BA.4 and BA.5 accounting for 64 percent of total cases in April compared to 18 percent in March. The European Centre for Disease Prevention and Control (ECDC) recently classified them as “variants of concern.”

“BA.4 and BA.5 have mutations in the spike protein on the surface of the virus that [may] evade immunity,” said Park Young-joon, head of the epidemiological investigation team at the Central Disease Control Headquarters during the briefing.

However, Lee Sang-won, head of the epidemiological investigations team at the Central Disaster and Safety Countermeasure Headquarters, explained that although the new subvariants spread a little faster, the severity rate or other factors “aren't very different” compared to previous lineages.

The BA.2.12.1 variant, which is known to have a 23 to 27 percent stronger transmissibility than the existing BA.2 (or Stealth Omicron), had 13 new cases added in Korea, raising the total to 19.

Health authorities said Tuesday that 11 came from overseas, and two were locally transmitted. This was the first time community spread was found with this variant. The previous six cases were all imported.

Of the local variant patients, one had received two doses of a Covid-19 vaccine, while the other had four shots including two boosters.

The BA.2.12.1 is already causing a new Covid-19 surge in the U.S.

According to the New York Times, the 7-day average for new cases as of Sunday was at 91,185 a day, a 61 percent increase from two weeks ago. In some hot spots in the Northeast and Midwest, daily cases have already passed the peak of last summer's Delta surge.

Along with the new variants found, the decline in Covid-19 infections in Korea is also slowing.

The KDCA said in a press release Tuesday that weekly numbers have been on a decline since the third week of March, but the decline has “slightly slowed down.”

It added the weekly average for new cases among the age groups between 10 to 19 and 20 to 29 increased from the previous week, and the figure is still high in the age group under 19 at 91.5 people.

The latest situation calls into question whether the 7-day mandatory quarantine for Covid-19 patients should be lifted. On April 25, the infectious disease classification for Covid-19 was downgraded to Class 2, but the government allowed for a four-week transition period before implementing changes, including the lifting of quarantines. That transition period is scheduled to end on Sunday.

The 7-day quarantine is likely to be maintained until late June, a JoongAng Ilbo report said, citing government sources.

A final decision will be announced Friday.

Meanwhile, the KDCA said Tuesday that it will start mass antibody testing this month to learn about naturally infected populations and evaluate the risk of the pandemic. It plans to survey 10,000 residents in 17 cities and provinces across the country aged 5 or older every quarter.

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