Japan can teach us that transmission is NOT the issue, diet is. Despite widespread mask use, Covid19 spread like wildfire in Tokyo, yet the mortality in Japan is among the lowest in the world. A diet rich in zinc, iodine & vitamin D has saved the population of Japan, not masks.
Plus the vast amounts of Epigallocatechin Gallate, or EGCG, a zinc ionophore (brings zinc to the cells), that the Japanese consume through their matcha green tea, green tea ice creams, etc: https://twitter.com/robinmonotti/status/1338049531909451776?s=19
Therefore do whatever you want at Christmas, wearing or not wearing masks will not make any difference, who you see & who you don't will not make any difference, but your diet will. Aim for a diet rich in zinc, zinc ionophores & vitamin D.
Transmission is not the problem. Obesity is linked to diet & to vitamin D deficiency. It's really not about masks but diet & movement, preferably outdoors in the sun without masks. Online life due to lockdowns only creates more vulnerability & deaths. No lockdown in Japan.
In terms of pre-existing immunity, this study proved pre-existing T-cell immunity for 40-60% of California residents. So it is not exclusive to Asia https://twitter.com/robinmonotti/status/1327529485592358913?s=19