A necessary hypothesis: China inoculated its population against C19 a year or more before pandemic outbreak

I am going to put this very briefly: There is significant evidence that viruses (plural) very similar to C19 were circulating in China (and less elsewhere in the world) as early as 2017. These early viruses conferred immunity to C19 and this accounts for the low IFR and C19 mortality rates in China, Japan, Taiwan, and other nearby areas. These early viruses also conferred immunity to about 50% of the populations of Europe and North America. That immunity from these viruses geographically centers around China, lessening with greater distance, strongly suggests they were used by the CCP to inoculate the Chinese population against C19. These viruses may have been less contagious than C19 but were thoroughly seeded within China to overcome that.