Earlier quoted context omitted.
Another coronavirus probably caused a worldwide pandemic starting in 1889. It killed a lot of people, but the survivors gained natural immunity which gave them significant protection against symptomatic reinfections. The same virus HCoV-OC43 is still endemic today. This seems relevant to the current pandemic. https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/175... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC…
I understand this is a reoccurring theme throughout history that lead to most of the endemic coronaviruses today. Omicron is truly fantastic; for example look at Ontario’s case count vs ICU count. Omicron has completely decoupled those graphs.
(but a larger number of mild breakthrough infections is not itself terrible news either as the mildness indicates a population becoming more resilient against the virus)