Japan: The Delta variant died out on its own. Because?
Japan seems to have completely or almost completely solved the Covid-19 problem, also from what can be read from the following graph on the number of cases:
Now Japan has achieved a high vaccination rate and, temperamentally, the Japanese citizen does not need strong incentives to maintain social distancing. This would already help explain the course of the disease, but there is much more.
As Japan Times points out, some researchers believe there was a mutation in the virus that greatly weakened it. The main reason could be related to the genetic changes that the coronavirus has undergone during its reproduction, a phenomenon that would lead to about two mutations per month . According to a potentially revolutionary theory proposed by Ituro Inoue, a professor at the National Institute of Genetics, the delta variant in Japan has accumulated too many mutations in the virus's non-structural error-correcting protein called nsp14. As a result, the virus struggled to repair errors in time , ultimately leading to the virus "self-destruct".
Studies have shown that more people in Asia have a defense enzyme called APOBEC3A that attaches viruses to RNA, including the SARS-CoV-2 virus which causes COVID-19, than people in Europe and Africa.
So researchers from the National Institute of Genetics and the University of Niigata set out to find out how the APOBEC3A protein affects the nsp14 protein and whether it can inhibit coronavirus activity. The team conducted an analysis of genetic diversity data for alpha and delta variants from infected clinical samples in Japan from June to October.
They then visualized the relationships between the DNA sequences of the SARS-CoV-2 virus to show genetic diversity in a diagram called a haplotype network. In general, the larger the network, the more positive cases it represents.
The alpha variant network, which was the main driver of the Japanese fourth wave from March to June, had five main groups with many mutations branching off, confirming a high level of genetic diversity. The researchers thought about the delta variant, which the U.S. Centers for Disease Control and Prevention says is more than twice as contagious as previous variants and could cause more serious disease in unvaccinated people, with much more genetic diversity. lively.
Surprisingly, they found that the opposite was true. The haplotype network had only two main groups, and the mutations seemed to suddenly stop in the middle of its evolutionary process. When the researchers continued to examine the virus's nsp14 bug-correcting enzyme, they found that the vast majority of nsp14 samples in Japan appeared to have undergone many genetic changes at the mutation sites called A394V.
" We were literally shocked to see the results, " Inoue told the Japan Times. “The delta variant in Japan was highly transmissible and had excluded the other variants. But as the mutations accumulated, we believe it eventually became a faulty virus and was unable to make copies of itself. Considering that the cases have not increased, we think that at some point during such mutations it has headed straight for its natural extinction . "
Inoue's theory, although innovative, would support the mysterious disappearance of the diffusion of the delta variant in Japan. While much of the rest of the world with similarly high vaccination rates, including South Korea and some Western countries, suffer from record waves of new infections, Japan appears to be a particular case as COVID-19 cases have remained. content despite the fact that trains and restaurants filled up after the last state of emergency ended. Perhaps the Japanese are truly genetically superior or, quite simply, the virus is destined to disappear.
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The article Japan: Delta variant died out on its own. Because? comes from ScenariEconomici.it .
This is a machine translation of a post published on Scenari Economici at the URL https://scenarieconomici.it/giappone-la-variante-delta-si-e-estinti-da-sola-perche/ on Mon, 22 Nov 2021 09:00:30 +0000.