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Almost all Japanese get the 18 needle BCG vaccination. My gf has the scar. The strain of BCG vaccination given is different in different countries. The strain given in Japan is per Wikipedia available in 50 countries Japan has higher than normal TB incidents than other devolped countries so they take it very seriously. If you are not immune by some age in school you get a second dose.

Most devolped countries that used to have mandatory BCG vaccination do not anymore. BCG vaccination (the strain given in Japan) might prevent or reduce severity of Corona but I think the studies still have to be done.

http://www.bcgatlas.org/index.php

https://en.m.wikipedia.org/wiki/BCG_vaccine

https://semi-sapporo.com/afterbirth/special-circumstances-on-tuberculosis-and-bcg-in-japan/

The data for COVID-19/SARS-CoV2 infection rates and death tolls is so noisy that it will take serious effort and a long time to weed out the irrelevant data and find what, if any, factors contributed to the widely-varying results. Genetics, culture, environment, hygiene, climate, nutrition, population density, age, psychology... who knows at this point? It might all be a crapshoot in the end no matter what, too.