99.5% of Confirmed Cases Are Delta Variant... 21% Are Breakthrough Infections

Medical staff are collecting samples at a temporary COVID-19 screening clinic set up at Seoul Station Plaza on the 3rd. [Image source=Yonhap News]

[Asia Economy Reporter Lee Chun-hee] The COVID-19 Delta variant has recently accounted for virtually all domestic confirmed cases. As the Delta variant spreads rapidly, the proportion of breakthrough infections among new confirmed cases has also reached 20.8%.

The Korea Disease Control and Prevention Agency's Central Disaster and Safety Countermeasure Headquarters for COVID-19 announced on the 6th that the detection rate of major variants and the Delta variant among domestic infection cases over the past week remained the same as the previous week at 99.5%.

Among 3,085 domestic confirmed cases analyzed, the Delta variant was detected in 3,070 cases, meaning that the majority of COVID-19 viruses circulating domestically are the Delta variant. This contrasts with the week of June 4th, when only 196 out of 642 cases (30.5%) showed major variants, and only 21 cases (3.3%) were confirmed as Delta variant, indicating that the Delta variant has now clearly become dominant in Korea.

Notably, in the 3rd and 4th weeks of September, one Alpha variant infection case was confirmed each week, but none were detected in this recent survey.

As the Delta variant, known to have higher infectivity, severity, and fatality rates than the original COVID-19 virus or other variants, spreads, the number of 'breakthrough infection suspected' cases?where individuals test positive for COVID-19 despite being 14 days past full vaccination?is continuously increasing.

As of the 26th, the number of confirmed breakthrough infection suspected cases reached 10,540, an increase of 2,768 from 7,772 the previous week. This corresponds to 0.053% of the 20,044,857 fully vaccinated individuals, or about 52.6 cases per 100,000 people, a significant rise from the previous week's 43.8 cases per 100,000.

The breakthrough infection suspected cases, which were only 2 in April, surged rapidly with 6,471 cases confirmed last month alone. Particularly, as of the 4th week of September, breakthrough infection suspected cases accounted for 20.8% of the total 13,280 confirmed cases, significantly increasing their proportion among all confirmed cases.

The proportion of the Delta variant among breakthrough infection suspected cases has also risen sharply. Among 2,331 cases where variant virus analysis was completed, major variants were confirmed in 2,103 cases (90.2%), with the Delta variant accounting for the majority at 2,070 cases.

The incidence rate of breakthrough infection suspected cases per 100,000 vaccinated individuals by vaccine type was highest for Janssen at 192.8, followed by AstraZeneca (AZ) at 49.3, Pfizer at 40.0, and Moderna at 3.5. Among those who received a heterologous vaccination with AZ for the first dose and Pfizer for the second dose, breakthrough infections occurred at a rate of 38.4 per 100,000.

This content was produced with the assistance of AI translation services.