Hi, Thanks for that interesting input. I've looked at a few studies since reading your comment, and will look at more. Apparently the potential protective effect of the BCG vaccine is intriguing to responsible researchers. I'll link you to several studies, (I disregard WHO because I think they are subject to political pressure and only offer the least controversial judgments). The most persuasive study for me was the one conducted in Israel, which tried to factor in a number of variables, including age and ethnicity. I found the Lancet article also offered a balanced discussion, which I found persuasive.
One article in The Scientist does a through review of evidence from different sources. This seemed to be a fair and well-researched discussion and left the question open. One idea covered in this article was that vaccinated children who did not form a scar after BCG vaccination showed a weak immune response. This is exactly the finding of post-vaccination immunity in smallpox: failure to form a scar resulted in poor protection against contagion.
You probably did not expect such a long response, but I do like to pursue ideas. Yours was a very interesting one:)