I’ve saw that the BCG vaccine very effective in Northern countries but as you get closer in Africa and south America it starts to lose it’s effectiveness
I’ve saw that the BCG vaccine very effective in Northern countries but as you get closer in Africa and south America it starts to lose it’s effectiveness
Comments
Poorly understood observation that is posited to be related by other factors which influence immune response against mycobacterium tuberculosis such as exposur to non-tuberculous mycobacteria or parasites such as helminths.
In short proximy to the equator is associated with other factors which can plausibly affect the vaccine effectiveness (such as the examples given above) but is easier to observe. Thus the association between proximity to the equator is true, but the causal pathway is more complex and passes through meaningful other factors.
Fallacy thinking that correlation implies causation
The assumption that correlation between events means that one event causes the other
Generally speaking, we have poor people living in the equatorial region. Lots of sanitary and tropical diseases. No money to treating TB, who is notorious for the lengthy treatment. And so, more vectors for transmission.