Covid, disappeared Delta variant in Japan: possible self-extinction. Here’s what it means

Although Japan is still struggling with the Sars-CoV-2 coronavirus syndemic, there is a profound difference between the Land of the Rising Sun and other nations: there the Delta variant has now disappeared. The high vaccination rate and the introduction of various anti-Covid measures have undoubtedly contributed to this important result, however, according to some Japanese researchers, the mutation of the virus could also have disappeared for another reason.

The possible self-extinction of the Delta variant


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A group of researchers from the National Institute of Genetics and the University of Niigata argues that the Delta variant may have disappeared due to an excess of mutations that would have led it to “self-extinguish”. It would then eliminate itself, naturally. All viruses mutate and in most cases this brings benefits to pathogens, which become more contagious or aggressive. In some rare circumstances, however, it can happen that the changes that occur during the viral replication process turn out to be counterproductive. Due to these “errors”, the virus becomes unable to replicate itself, resulting in an inevitable disappearance. Researchers believe that the Delta variant may have met a similar fate in Japan.

The decline in infections in Japan

According to Professor Ituro Inoue, only the disappearance of the Delta variant can justify the rapid collapse of infections that have occurred in recent months. Around August 20, the daily infections were about 24-25 thousand a day, while today there are a few dozen infections every day. The average death rate also dropped significantly, from more than 60 per day to 3. Researchers believe the Delta variant would have accumulated too many mutations in the nsp14 protein, responsible for correcting copying errors during viral replication. Its failure would have caused the viral agent to self-destruct.

The conclusions of the experts

The Japanese experts formulated the hypothesis of the self-extinction of the Delta variant during an analysis of the impact of the enzyme APOBEC3A (common in the Asian population, but not in the European and African ones) against the nps14 protein. This study led the researchers to note that the genetic diversity of the Delta variant was much smaller than that of the Alpha variant. This led Professor Inoue’s team to discover that this version of the virus had undergone an evolutionary block, due to the accumulation of mutations on the nps14 protein. The natural extinction of the pathogen seems to be the only plausible explanation for the significant decline in infections. Inoue pointed out that the Delta variant could face a similar fate in other parts of the world as well. However, this is a less probable scenario, considering that a lower number of nsp14 mutations have been found abroad than in Japan.