Last August, Japan was in the middle of the fifth and largest corona virus since the outbreak. More than 20,000 cases were registered daily.
That relapse was driven by the delta variant, which revolutionized the world and, due to its greater spread, transformed other mutations in the pathogen.
But that month was also a turning point for the Asian nation.
Since then The cases dropped at a dizzying rate Today, as many countries with similar vaccination percentages fight new infections, Japan breathes easier, and this Tuesday, November 23rd, more than 100 new infections were recorded.
One explanation for the catastrophic fall is that, according to the panel of scientists, the delta variant may actually be “self-destructive.”
Is this possible? Will this happen again in other parts of the world?
There may be several hypotheses behind this sudden decline in the incidence and occurrence of delta variation.
More than 75% of residents have already been vaccinated in Japan and the widespread use of social remote measures and masks is closely followed by the population, according to a national media report.
But other countries face similar conditions and file many more daily cases.
In Spain, for example, 80% of residents have already received the full vaccine and continue to use masks in closed areas.
This Tuesday, despite a third of Japan’s population, it recorded nearly 7,000 daily cases.
It was this kind of comparison that guided Japanese scientists based on genetic observations to handle the hypothesis of the “self-destruction” of the delta variant.
“The delta variant in Japan was highly contagious and congested in other species. But as mutations accumulated, we think it changed. A false virus that cannot be copiedIturo Inoue, a geneticist at the National Institute of Genetics in Japan, told the newspaper Japan Times.
“Considering that the number of cases has not increased, we believe that at some point during these mutations the virus went straight on. Their natural destructionInoue added.
The delta variation in Japan suddenly disappeared, much to the surprise of many.
Especially recently many Western countries, with improved vaccines, had to resume stringent control measures.
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Despite the fact that trains and restaurants have been packed since the end of the last state of emergency last October, Japan appears to be a strange phenomenon where corona virus cases fall into free fall.
The disappearance of different types of a virus is one thing This has been going on since the beginning of the epidemic.
“It happens all the time in animal and human viruses. Remember that alpha, beta and gamma variants are often altered by delta types,” Julian Tong, a virologist at the University of Leicester in the United Kingdom, told the BBC. Mundo.
“It’s really a matter of virus fitness in any host. Perhaps the virus in the Japanese population’s immune system has changed the way it works there. Time will tell whether this will happen in another country“Tang adds.
Previous studies have shown that people with the protective enzyme APOBEC3A in Asia are more susceptible to a variety of viruses, including the corona virus that causes COV-19, compared to those in other regions such as Africa and Europe.
With this, researchers from the National Institute of Genetics and the University of Nicota studied whether this enzyme could inhibit the activity of the corona virus.
The team compared genetic diversity data for delta and alpha variations in affected clinical samples in Japan between June and October.
During the study, they observed that the mutations in the virus abruptly stopped in the middle of its evolution. They are defective And the replication of the virus was inhibited.
“They found mutations in the nsp14 protein, which is associated with the correction of reflex defects. If there are more mutations in this protein than normal, these It can be disabled or inefficient, It can cause infections, “said Jose Manuel Batista, a professor of biochemistry and molecular biology at the University of Madrid in Spain.
Although Batista believes that cases drop abruptly for reasons such as mass vaccination and long-distance operations, the steepness of the infection curve attracts his attention.
“The normal thing is that when people isolate themselves, it decreases little by little, because the victims who are already there continue to be reported after a few days. The drop in cases is very dramatic and exaggerated and indicates that the theory of self-destruction is possible.” The educator adds.
Despite the surprising drop in cases in Japan, scientists are cautious and avoiding a diagnosis of what might happen in the future.
The epidemic continues to develop, despite vaccinations and control measures. The world is not yet safe from new sprouts.