Thank you. Pretty rookie mistake when live virus infects people, especially healthy children! I mean, that's the first and main thing you worry about when using a live vaccine. And then it mutates and you start from square one. And there's another aspect here: In the 50's-80's, Big Pharma especially some Euros were caught testing their shit on poor African populations. Giant savings to skipping the human trials protocols like informed consent, and if it works, you make a mint in rich countries.