Reason for Rapid Spread of Delta Variant: "1000 Times More Virus in the Nose"

[Image source=Reuters Yonhap News]

Nature Publishes Research Results by Chinese Researchers

[Asia Economy Reporter Kim Yuri] The rapid spread of the COVID-19 Delta variant has been attributed to the speed of viral replication.

The scientific journal Nature reported on the 23rd that the amount of virus in the nasal passages of people infected with the Delta variant was more than 1,000 times greater than that of people infected with the pre-variant virus. This suggests that the replication speed of the Delta variant virus is much faster than that of the pre-variant virus.

Professor Jing Lu's team at the Guangzhou Guangdong Provincial Center for Disease Control and Prevention in China conducted a follow-up study on 62 individuals who were the first in China to be infected with the Delta variant and isolated. They compared their infection patterns with those of 63 people infected with the pre-variant COVID-19 virus last year.

According to the paper they published on the medical preprint site medRxiv, the density of viral particles in the nasal passages of Delta variant-infected individuals was up to 1,260 times higher than that of those infected with the original virus.

The incubation period was also found to be shorter. Those infected with the pre-variant virus first tested positive for the virus an average of 6 days after exposure, whereas Delta variant-infected individuals tested positive 4 days after exposure.

These results suggest that the Delta variant has strong transmissibility due to a high viral load and a short incubation period. However, whether the Delta variant poses a greater risk of severe illness than the original virus, and its ability to evade the immune system after entering the body, have not yet been clarified.