[perl4ever]

"there's an increasing suspicion that countries still using the BCG vaccine for tuberculosis might be seeing [1]way lower infection rates"

Obvious to me, perhaps dumb, question - if countries that were slower to change vaccination regimes have some advantage, then wouldn't we see older people in the countries that did change also at an advantage? Yet all reporting seems to be that older people are harder hit.

[coliveira]

BCG vaccine requires a booster every few decades, so it becomes less effective over the years. Apart from health issues related to age, this would explain why old people are at higher risk.