hankyoreh

Health workers at a temporary screening center in Seoul are pictured on Tuesday. (Yonhap News)

One in three COVID-19 cases over the past week were caused by Delta, the most infectious variant of the coronavirus, the South Korean government reported. As Delta spreads beyond greater Seoul to resort areas such as Gangneung, in Gangwon Province, some expect that Delta will become the dominant variant, accounting for more than half of all COVID-19 cases, within the month.

Korea’s Central Disease Control Headquarters (CDCH) said Tuesday that major virus variants were detected in 1,001 of 2,124 COVID-19 patients who underwent genomic testing over the past week (July 11-17). That represents a detection rate of 47.1%. In effect, around half of local COVID-19 patients are being infected with major virus variants.

Significantly, 701 of those COVID-19 patients had the Delta variant or 33.9% of the total. That was 10.6 points higher than the previous week (July 4-10), when Delta was detected in 23.3% of COVID-19 patients tested for variants.

The Delta detection rate in the greater Seoul area over the past week was 10 points higher than the previous week, rising from 26.5% to 36.5%. The Alpha variant was detected in 282 cases, representing 13.3% of the total.

The problem is that Delta is spreading beyond the greater Seoul area. Between Wednesday and Monday, Gangneung reported 111 cases of COVID-19, and Delta was detected in a sample survey. Gangneung instituted Level 4 of social distancing on Monday, becoming the only local government body not in the Seoul area to do so.

“When Gangwon Province asked the Korea Disease Control and Prevention Agency to [check for] variant samples, Delta turned up in at least 60% of the cases in the sample,” Gangneung mayor Kim Han-geun said in a press briefing on Sunday.

“Delta was detected in all the Gangneung cases in the sample that was surveyed. We’re assuming that Delta is responsible for all the rapid spread of the virus at the moment,” Kim said.

“We aren’t seeing this so much in Sokcho or Yangyang so far, but in Gangneung, Delta is being detected with greater frequency,” an official from the Gangwon Province Institute of Health and Environment told the Hankyoreh in a telephone interview Tuesday.

Korea’s disease control authorities predict that Delta will become the dominant viral variant even sooner than originally expected.

“Because the Delta variant is so transmissible, it’s going to make an increasingly large contribution to [the outbreak], whether through transmission between individuals or in clusters. We think that Delta’s rise to dominance over other variants will gradually accelerate,” said Lee Sang-won, head of epidemiological research for the CDCH.

Medical experts offered the same analysis.

“The current figures are underestimated because the virus variant detection rates represent what was happening a week ago and because we aren’t testing all the cases in infection clusters,” said Jung Jae-hun, a professor of preventive medicine at Gachon University.

“I basically think that Delta is driving the current wave of infections. It will become the dominant variant within the month.”

“Delta’s move toward dominance is one of several negative circumstances. Aside from the restrictions on private gatherings after 6 pm, the current restrictions in Level 4 of social distancing aren’t as strong as what we implemented in the third wave, such as banning indoor dining at restaurants. I don’t think we’re going to have the dramatic effect we saw then,” said Kim Woo-joo, a professor of infectious disease at Korea University Guro Hospital.

The current surge of COVID-19 cases is expected to continue for the time being. The reproduction number, which indicates the number of people infected by a given patient, has risen from 0.99 in the fourth week of June (June 20-26) to 1.2 in the fifth week of June (June 27-July 3), 1.24 in the first week of July (July 4-10), and 1.32 last week.

“Given the reproduction number for each week, there’s no evidence to say that the wave is slowing yet. The wave is still underway, and infections are expected to keep rising in the future,” said Lee Sang-won, who urged the public to maintain social distancing and disease control restrictions.

By Seo Hye-mi, staff reporter

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