Japan has had remarkable success battling the pandemic. They were slow with the vaccine rollout this spring, but now their vax rate is well over 70%, and currently the COVID daily new case count is about 100 cases per day. For the entire country.
It’s easy to point to near-universal mask usage and high vax rates as the cause for this success. Certainly they do matter, but another theory has been put out there:
TL,DR: the theory suggests that the virus mutated in a way that rendered it unable to make copies of itself. The hand-waving part is the idea that this crippled version of the Delta variant somehow outcompeted the more virulent version of the Delta variant. Wouldn’t the non-crippled version continue infecting people, even as the crippled version stopped propagating to new victims? What am I missing here?
It’s hard to make sense of, to be honest. You’re right, the notion that a virus could cripple its own reproductive capacity and then outcompete the unmutated virus… on its face, without any deeper information, it seems like nonsense.
The level of detail in the article makes it seem like someone’s thought this through, so I hesitate to say these people are outright idiots. The journalist must have fumbled some key detail that would help make sense of this.
There appears to be a legitimate phenomenon called “Mueller’s Ratchet.” I don’t pretend to understand it fully, but here is a good article article that explains it.
Basically, under certain conditions, certain viruses may genetically bottleneck themselves into an increasingly dead-end path. Apparently it’s not well-observed in the wild but is theorized to affect respiratory coronaviruses more than others.
What would make more sense to me would be a mutation that spreads very well, but doesn’t make people sick, resulting in immunity to the actual variant.
From the US perspective it seems like SARS just disappeared, but that’s because Pacific Rim countries went on full alert and stopped it before it spread here in large numbers.
I think that contributed to the US letting it get out of hand. “Oh, it will just be another SARS scare” not realizing that SARS nearly became a global calamity like COVID.
My understanding is that SARS was not significantly contagious until after onset of symptoms, which made it a whole different beast than C19. A disease spread by measurably sick people is possible to contain the way that SARS was. But even countries that are good at masking and have very effective testing and public health systems have required draconian measures to actually contain C19.