If you're a developed country swimming in vaccines like the US, do you let the delta strain go for it? Drawing it out with lockdows only makes the vaccine less effective, and once you lock down, it becomes clear there is no exist strategy. What if you're a large city with 80% vaccination rates? Will there be anger over preventable lockdowns? What if you're facing a recall election?
What if you're Europe, have moderate vaccine coverage, but likely won't be able to vaccinate to herd immunity for the same reasons as the US?
In hindsight, knowing the virus would be 2.5x worse in a year and a half and half your population would have no interest in the vaccine, should you have let it spread?
Citation needed.
> COVID is becoming more deadly over time because there is a selective pressure towards more transmissibility. More transmissibility can increase the severity of illness if the virus more readily replicates or more easy infects human cells.
I read that as talking about infection fatality rate (IFR). I'm not aware of any evidence that covid's IFR is increasing.
It seems that the Alpha variant is more virulent than the original, but it's hard to measure virulence to a high degree of confidence.
IFR is not quite the right thing to measure, we are interested in differences in mortality due to mutation of the virus, but there are many confounding variables in the quality of treatment and populations that get infected to remove. e.g. if a virus stayed exactly static you would expect mortality to decrease over time as better treatments are found.
Viruses only become less deadly if they are so deadly that hosts die before they can pass on the virus. No such pressure exists for COVID as patients are infectious during the incubation period.