"Delta Variant Infected Patients Release 300 Times More Virus on Symptom Onset Compared to First Wave Cases (Comprehensive)"

On the 24th, when the first dose vaccination rate for COVID-19 in Korea surpassed 50 percent, citizens who visited the COVID-19 vaccination center set up at Bukahyeon Cultural Center in Seodaemun-gu, Seoul, were observed for adverse reactions after receiving the vaccine. Photo by Jinhyung Kang aymsdream@

[Asia Economy Reporter Seo So-jeong] Patients infected with the Delta variant were found to release more than 300 times the amount of virus on the day symptoms appeared compared to patients from the first wave.

On the 24th, the Central Disease Control Headquarters announced that they analyzed the amount of virus in respiratory specimens confirmed positive for COVID-19 after symptom onset to examine the initial transmissibility of recently occurring Delta variant cases in Korea, revealing these results.

The headquarters converted the daily average test values into viral load for 1,848 specimens from Delta variant-infected patients and 22,106 specimens from the first to third waves in Korea, which mainly detected genotypes (S type, V type, GH type), for up to 14 days after symptom onset.

The analysis showed that on the day symptoms appeared (day 0), Delta variant patients had about 300 times more virus than patients from the previous epidemic strain (first wave). However, the difference decreased over time, with about 30 times more virus on day 4 and about 10 times more on day 9, and after day 10, there was no difference in viral load among subjects, confirming that the viral load decreased similarly to previous strains.

The headquarters explained, "The high viral load in the early stage of symptom onset in Delta variant patients suggests a high potential for transmission."

Kim Eun-jin, head of the testing and analysis team at the headquarters, said, "The coronavirus has undergone several changes in transmissibility, and compared to the virus during the first wave last year, the viral shedding amount at the onset of illness increased by more than 10 times during the second and third waves."

She added, "Currently, the Delta variant virus, which is at the center of the fourth wave, has been confirmed to shed more than 20 times the amount of virus compared to the second and third waves."

Lee Sang-won, head of the epidemiological investigation and analysis team at the headquarters, said, "For Delta variant infections, about 300 times more virus is released compared to the virus during the first wave," but added, "However, this does not necessarily mean that transmissibility has increased by the same amount."

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