When the delta variant became the most dominant strain of the novel coronavirus in the United States in July, experts sounded alarm over its ability to be transmitted rapidly compared to other strains. At its peak, the delta-driven wave recorded over 127,000 cases in mid-September. Since then, the cases have steadily declined, but still not enough for the country to lower its guard down in the face of COVID-19.

While the U.S. is still struggling with the effects of the pandemic, Japan has surprisingly observed a significant drop in its number of daily cases, causing experts to believe that the delta strain is close to extinction in the Asian country. And based on what they have witnessed so far, the reason for the sudden nosedive in cases could be rooted to one of the virus’s innate abilities — mutation.

Japan’s Present-Day COVID-19 Situation

In August, Japan was recording around 23,000 cases per day amid the delta wave in the country. Three months later, Japan is recording an insignificant number of cases per day. The average daily cases being reported in the country as of late is 140. In Tokyo, which was the epicenter of the outbreak during the first wave of the pandemic, only 16 new cases were reported on Friday, according to New York Post.

As the delta wave reached an abrupt standstill, local experts weighed in on what could have led to the sudden drop in transmissions. Among the theories going around is the idea that the delta strain has already exhausted its mutations and has now reached a point where it is already self-destructing.

One of the common characteristics of viruses is their ability to mutate or evolve. Whenever a virus undergoes replication, its genes also goes through processes that involve “copying errors.” Over time, the random processes build up and lead to changes in the overall makeup of the virus. These mutations vary greatly, leading some strains to be more transmissible and more virulent. But there are also instances when the mutations become “evolutionary dead ends,” as what experts would like to call them.

A Promising Discovery About The Delta Strain

A group of researchers led by the National Institute of Genetics, Mishima, Japan conducted a study on the delta virus. While focusing on the strain’s error-correcting enzyme called nsp14, they found that certain genetic changes in the virus led to an abrupt stop in its evolution process.

According to the researchers, they noticed that at a certain point, the delta variant struggled to repair the errors but continued to replicate itself. This ultimately caused the virus to take care of its own demise. Ituro Inoue, a genetics professor at the institute, referred to the process as “self-destruction,” and he said that they were all shocked by this discovery.

In relation to what is happening in the country right now, Inoue told The Japan Times that their discovery could help explain why the number of cases in Japan suddenly dwindled in the recent weeks.

“Considering that the cases haven’t been increasing, we think that at some point during such mutations it headed straight toward its natural extinction,” he was quoted as saying by the outlet.

Could Mutation Be The Answer To The Delta Problem?

University of Reading’s Biomedical Sciences and Biomedical Engineering Division head Dr. Simon Clarke echoed a similar sentiment when asked how the delta strain of the virus could die out. In a dialogue with British newspaper The Sun, he noted that after world-dominance, the virus could move toward the course of self-extinction on its own.

“The virus accumulates too many mutations and therefore stops being able to replicate. When you get a virus like that, it just dies out. It’s like a person that never has children, their genetic material stops, end of the road,” Dr. Clarke explained.

Even though the findings of the Japanese scientists seem promising, Dr. Clarke warned that the so-called “evolutionary dead ends” only happen in a “very small subset of cases.” It is also important to note that similar to humans, not everyone stops producing children.

“There will still be a lot of coronavirus around that is capable of infecting people and will do just that until we have sufficient immunity or we can break the chains of transmission,” said Dr. Clarke.

In the case of Japan, other experts believed that apart from the theorized self-destructing mutations, one major reason why the cases there plummeted could be due to the country’s high vaccination rate. As of late, 75% of the Japanese people have been double-jabbed against COVID-19.

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