A fringe theory—that the novel coronavirus can mutate into a harmless new form—seems to have given some people false hope that the pandemic, now entering its third year, might end all on its own, regardless of what government officials, scientists, and everyday people do.
This COVID “self-extinction” theory isn’t new. It got some traction in the media in the spring under slightly different terminology.
The theory was almost certainly wrong then, and it’s still probably wrong now, experts told The Daily Beast. “I think self-extinction is vanishingly unlikely,” Jesse Bloom, an investigator at the Fred Hutchinson Cancer Research Center in Washington State, told The Daily Beast.
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It’s tempting to believe SARS-CoV-2 will just… go away. Without expensive, politically fraught efforts to vaccinate everyone. Without unpopular mask mandates and restrictions on schools and businesses. Without anyone sacrificing anything in the interest of public health.
But that’s most likely wishful thinking. And potentially dangerous if enough people indulge in it. Beating COVID probably means fighting it with every tool in our kit. Because, let’s be honest, it’s not looking like it’s going to beat itself.
A smattering of headlines announced the current interest in the possibility of COVID self-extinguishing. “Dominant Delta variant ‘may mutate itself into extinction,’ scientists say,” The New York Post teased on Nov. 22. “Covid 19: New research suggests Delta strain ‘drove itself to extinction’ in Japan,” the New Zealand Herald crowed the same day.
All the stories cite the same news story promoting the same claim. A Nov. 18 story in The Japan Times in which Ituro Inoue, a professor at Japan’s National Institute of Genetics, described some preliminary research he and his team had done on the SARS-CoV-2 virus genetic structure and changes over time.
The upshot, according to Inoue’s theory, is that SARS-CoV-2 basically hit an evolutionary brick wall, piling bad mutation on top of bad mutation until it rendered itself impotent.
Inoue’s team’s research isn’t published in a science journal yet, to say nothing of being peer-reviewed. That didn’t stop The Japan Times from repeating Inoue’s claims without a lot of caveats. Neither Inoue nor The Japan Times responded to requests for comment.
Scientists in Japan and across the world urged skepticism. “I know some experts are saying such a ‘self-extinction’ thing, but I will not bet on it,” Tanaka Mikihito, an expert on pandemics at Waseda University in Tokyo who also holds a Ph.D in molecular biology, told The Daily Beast.
To be fair, there’s a good reason Inoue grasped for a theory—a desperate stretch though it might be. He was trying to explain Japan’s very odd winter.
Japan, like much of the world, suffered a huge spike in COVID infections this fall as the highly transmissible Delta variant—“lineage” is the scientific term—became dominant, displacing less dangerous forms of the virus.
But Japan’s Delta wave ended relatively quickly in mid-September. And after that, cases dwindled to, well, nearly zero. Just a hundred or so new cases a day in a country with 126 million people. This at a time when many other countries, including the United States, were seeing fresh surges fueled in part by the new Omicron lineage.
Inoue wanted to understand what happened. He and his team inspected samples of Delta infections in Japanese residents and discovered something interesting: mutations in the NSP14 protein, which helps a virus sneak past our immune systems.
Scientists have long assumed that deliberately altering NSP14 in a particular viral lineage—using, say, a special drug on a bunch of patients—could make it harder for that lineage to spread.
But Inoue’s team assumed that the Delta lineage present in Japan somehow evolved a weaker NSP14 all on its own.
“We were literally shocked to see the findings,” Inoue told The Japan Times. “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. Considering that the cases haven’t been increasing, we think that at some point during such mutations it headed straight toward its natural extinction.”
In other words, if the theory holds, Delta became widespread in Japan at the same time that it became harder to transmit. A surge in Delta cases crowded out less aggressive lineages then abruptly ended when changes to the NSP14 protein blocked further transmission.
It would be as though a fast-breeding family of rats moved into your attic, scaring off all other pests. Then all the rats abruptly died, leaving you pest-free.
As an explanation for Japan’s weirdly low rate of new COVID cases this winter, Inoue’s theory is a tantalizing one. But it falls apart quickly under close scrutiny, especially considering that Japan’s high vaccination rate plus widespread masking and a little luck might be all the explanation we need for the country’s current reprieve from infections.
Edwin Michael, an epidemiologist at the Center for Global Health Infectious Disease Research at the University of South Florida, took Inoue’s theory into account when he mulled Japan’s low-COVID winter. “Initially, it was thought that the Delta variant there accumulated too many mutations during the summer resurgence that were deleterious to its own survival and hence thought to be a ‘self-extinction,’” Michael told The Daily Beast.
But Michael said he couldn’t figure out how a lineage could, at roughly the same time, both lose its transmissibility and become dominant. Inoue’s theory is “hard to reconcile with why such a mutant was able to spread widely such that most of the Japanese population caught this mutant leading to large-scale extinction of the virus,” Michael said.
More to the point, viruses as a rule almost never evolve in ways that lead to their own extinction. “I have never seen one that is widespread and just goes away,” Lawrence Gostin, a Georgetown University global health expert, told The Daily Beast. “I can’t think of a single example of that ranging from novel influenza to smallpox, polio and childhood diseases. Viruses don’t just go extinct.”
If that’s what Delta did in Japan, it would be truly unprecedented.
Inoue’s theory itself isn’t unprecedented, however—although it’s very likely wrong. A similar idea gained some traction this spring, starting with a claim in the pages of The New Yorker. Jason McLellan, a structural biologist at the University of Texas at Austin, told the magazine that the novel coronavirus’s spike protein, which helps the pathogen to grab onto and infect our cells, could mutate only so many times before it just … stopped changing.
“There’s just not a lot of space for the spike to continue to change in ways that allow it to evade antibodies but still bind to its receptor,” McLellan said. “Substitutions that allow the virus to resist antibodies will probably also decrease its affinity for [the receptor].”
In his theory, SARS-CoV-2 can either dodge our antibodies or stick to our cells. But it can’t do both. “It has a finite number of options,” McLellan said. And that, he claimed, should doom the virus to lose power over time.
Experts quickly challenged McLellan’s theory. “We’re not in a position to forecast that evolutionary changes are indicative of the virus being trapped, cornered or otherwise weakened,” Anna Fagre, a University of Colorado microbiologist, told The Daily Beast.
“I haven’t seen any indication that SARS-CoV-2 is running out of evolutionary space,” Bloom chimed in.
History proved the skeptics right. Since McLellan projected the novel coronavirus’ genetic dead-end, the pathogen has produced several major new lineages, each as bad as or worse than the previous. Delta. Omicron. Even a sublineage of Omicron that’s hard to distinguish using standard tests.
McLellan defended his spring comments as “more nuanced” than critics gave them credit for. He told The Daily Beast he was just trying to explain that the novel coronavirus’s spike protein has only so many amino acids to choose between as it evolves.
As for the current self-extinction notion, that’s “outside my area of expertise,” McLellan told The Daily Beast.
The coming months seem likely to disprove Inoue’s self-extinction claim. Everything we know about viruses points that way. “We must remember that a virus is not a living thing—it depends on infecting cells so it can replicate,” Stephanie James, the head of a COVID testing lab at Regis University in Colorado, told The Daily Beast. “When it is done with one host, it must be able to transmit to another to keep perpetuating in a community. So it is more advantageous for a virus to be transmissible.”
But let’s give McLellan and Inoue and any other future proponents of COVID’s purported potential for self-sabotage the benefit of the doubt. Say one lineage or another does something unprecedented and blunders into a genetic dead-end.
Even that wouldn’t end the pandemic, James said. Not when there are so many other lineages in circulation. “Even if one variant were to become less transmissible, my concern is that this would simply open a niche for another variant to take its place.”
All that is to say, it’s probably a bad idea to sit around waiting for the pandemic to end itself. The smarter approach is the one we’ve taken all along: Urge people to wear masks, avoid crowds and—most importantly—get vaccinated and boosted.
