119 Additional Omicron Subvariant Cases... Family Secondary Attack Rate 25% (Update)

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[Asia Economy Reporter Jo In-kyung] A sublineage of the Omicron variant, known to have higher transmissibility than the existing COVID-19 Omicron variant, was additionally detected 119 times domestically. The secondary attack rate of the new variant among household contacts of infected individuals was found to be similar to that of the Omicron variant.

The Central Disease Control Headquarters announced on the 21st that a total of 119 Omicron sublineages were newly identified last week (3rd week of June), including 69 cases of Omicron BA.2.12.1, 12 cases of BA.4, and 38 cases of BA.5, and epidemiological investigations are underway.

So far, the Omicron sublineages detected domestically include a total of 196 cases of BA.2.12.1, 26 cases of BA.4, and 73 cases of BA.5.

Among the 69 newly confirmed BA.2.12.1 cases, 36 were domestic infections and 33 were imported cases. Of these, 25 cases were detected in arrivals from the United States.

BA.4 includes 7 domestic infections and 5 imported cases, with more cases transmitted domestically. BA.5 includes 27 domestic infections and 11 imported cases.

BA.2.12.1, which spread mainly in the United States, is known to have about 20% higher transmissibility than BA.2, which itself is about 30% faster in transmission than the original Omicron variant. BA.4 and BA.5, which spread mainly in South Africa, also show faster transmissibility than BA.2.

The detection rate of BA.2.12.1 increased from 1.8% in the 4th week of May to 2.9% last week. During the same period, the detection rate of BA.2 increased from 33.5% to 34.8%, while the detection rate of BA.2.3 decreased from 60.2% to 56.9%.

The cumulative domestic detection counts of Omicron recombinant variants XQ, XE, and XM are 5, 6, and 2 cases, respectively.

As of the 14th, the Central Disease Control Headquarters reported that the secondary attack rate among household contacts (family members) of individuals infected with Omicron sublineages and recombinant variants was 25%.

Among 158 individuals whose household contact tracing was completed, 24 households (35.8%) out of 67 households with at least one household family member experienced additional transmission. Furthermore, among 152 household contacts in these 67 households, 38 were newly confirmed positive, resulting in a 25.0% secondary attack rate.

The secondary attack rate among household contacts of sublineage variants was 20.8% (26 out of 125), while that of recombinant variants was 44.4% (12 out of 27).

Park Young-jun, head of the epidemiological investigation team at the Central Disease Control Headquarters, stated, "Compared to the early Omicron variant outbreak when the secondary attack rate among household contacts was in the high 20% to high 30% range, the secondary attack rates for sublineage and recombinant variants among household contacts are not at a high level and are considered similar. However, since the number of analyzed subjects is not large, continuous monitoring is necessary," he added.

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