Actually I think that Bulgaria is the only country in EU which is still doing it.
Back in the times our country was part of the Soviet Union and I think that this method is old, but...
Every bulgarian have that scar because as I told you they injected us in the hospital against smallpox,tuberculosis and etc.
I lived in the States and I’m absolutely sure that they are not the most vaccinated population. Actually it should be some of the countries in Latin America.
I have seen that same scar on older generations in the US. Boomers, mostly.
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.