NO. 153 / Sep 6, 2021
The COVID-19 situation has been prolonged and multiple variants even as vaccines are being developed. The COVID-19 has spike proteins on the surface, and it binds with a receptor called ACE2 in the cells and penetrates the body. Vaccines are created based on the spike proteins’ gene arrangement of COVID-19, which binds with COVID-19 instead of ACE2 receptors to neutralize penetration. In other words, the worst situation is if the spike proteins’ gene sequence mutates to better bind with ACE2 receptors and not with the vaccine.
Based on this vaccine resistance and infectiousness, the World Health Organization (WHO) divides the variants into two stages: Variant Virus of Interest (VOI), Variant Virus of Concern (VOC). A “Lambda variant” has recently become a hot topic in VOIs. The first sample was found in Peru in December 2020. It is resistant to vaccine antibodies. The more serious VOCs are as follows: the first is the “Alpha variant” discovered in the United Kingdom (U.K.) in September 2020. It is 75% more contagious than the conventional virus, and it has mutated to avoid the human immune system. The second is the “Beta variant”. The first sample was found in South Africa in May 2020. As in the case of the “Alpha variant”, the Beta variant is more contagious than the conventional virus, but it is also known to resist vaccine antibodies. The third is the “Gamma variant”, reported to have been discovered in Brazil in November 2020, which combines the contagiousness of the “Alpha variant” and the resistance to vaccine antibodies of the “Beta variant”. The contagion is 152% stronger than the conventional virus. Finally, there is the “Delta variant”, whose first sample was found in India in October 2020. On June 18, 2021, the WHO predicted that the “Delta variant” would become a globally dominant species. It also has vaccine antibody resistance and strong contagious power. In particular, the Basic Reproduction Number (R_0), an index that refers to the number of patients carrying the virus, is known to be between 5 and 9. This fact means that a person infected with the Delta variant can infect five to nine other people, which is 2.5 times higher than the power of the existing COVID-19.
However, the global vaccination status is estimated at 70% to 75% in Canada, U.K., and France, among other countries, based on at least one vaccination, followed by the United States (U.S.), and Brazil at about 60% and Korea and Japan at about 50%. In addition, Korea has a nationwide vaccine pre-booking system and a location-based remaining vaccine reservation system based on Naver Map and Kakao Map with Internet certificates.
Now Korea’s R_0 exceeded 1. It is considered impossible to reach collective immunity with vaccines only, as the R_0 increases significantly, although it is still possible. COVID-19 demands a swift response.
By Noh Hyun-jin, AG Reporter
noh0605@ajou.ac.kr
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