New research suggests that the more contagious Covid-19 Delta variant may mutate itself into self-extinction, as it did in some pandemic-hit countries.
Scientists at Japan’s National Institute of Genetics said the Delta strain headed toward a “natural extinction” in Japan after several mutations made it unable to copy itself.
In the 125-million-people country, health authorities issued a maximum alert since the first infection caused by the most transmissible variant was detected this year.
Japan was hit hard by a fifth Covid-19 wave in late summer, with its daily case toll peaking at 26,000. However, the nation’s biggest coronavirus pandemic wave suddenly came to an end and has almost completely faded.
In the Japanese capital Tokyo, the world’s largest city with 40 million people, the government only reported 16 new cases on Friday and only six infections on Monday. In recent weeks, Japan recorded fewer than 200 cases and the first day without a coronavirus-related death in more than a year.
According to genetic experts, that drop is because the strain caused its disappearance through mutation.
Experts explain that a virus’ genes suffer random “copying errors” as it replicates over time, causing changes in its composition. Mutations can cause a virus to bypass immunity or be more transmissible.
However, in some cases, such mutations become “evolutionary dead ends,” the researchers stated.
Professor Ituro Inoue, a genetics expert, developed a “potentially revolutionary” theory, saying that the Delta variant accumulated too many mutations in the virus’ error-correcting protein nsp14.
The virus couldn’t repair its errors on time and kept replicating, causing its self-destruction, Professor Inoue said.
“The Delta variant in Japan was highly transmissible and keeping other variants out. But as the mutations piled up, we believe it eventually became a faulty virus and it was unable to make copies of itself,” he stated, adding that investigators were “literally shocked” by the findings.
While many attribute the drop in Covid-19 infections to high vaccination rates, the professor said the Delta variant would continue spreading if it were “alive and well.”
Other experts said Professor Inoue’s findings could be used to develop “promising” new medical treatments.
