Recently a number of publications looked at the association between COVID-19 morbidity and mortality on one hand and countries ' policies with respect to BCG vaccination on the other .
that population age is a very significant confounding factor
Recently a number of publications looked at the association between COVID-19 morbidity and mortality on one hand and countries ' policies with respect to BCG vaccination on the other .
This study shows that population age is a very significant confounding factor that explains the rates of infections much better and has a solid biology mechanism which explains this correlation .